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Discussion Starter #1 (Edited)
Hi,

I've an D250 light weight pickup that won't start.

Its been sitting up a few years, but once a year we've tried to turn it over just to keep everything lubricated. But we didn't actually run it.

I put fresh gas in it, charged the battery, replaced the oil, replaced the transmission fluid. Just general maintenance stuff in preparation.

I do know its getting a Spark, because spraying some starter fuel into the Throttle Body throat causes it to fire briefly and turn over like its going to run and then dies when the fuel runs out. I think that rules a few things out.

To be methodical, after reading here and obtaining the OEM Service manual and OEM Parts manual and reading. I bought a replacement Mopar Automatic Shutdown Relay (Fuel Pump Relay), a new Mopar Distributor Cap, a new Mopar Distributor Rotor, and a new Mopar Distributor Hall Effect - Pickup Coil Sensor.

I live some hours away from where the vehicle is stored and its a long term weekend project. So I do as much research and parts obtaining as I can and then try things.

I have not replaced anything on the D250 yet.

But I was thinking there should be some sequence of testing I should go through in order to maximize the possibility of finding the problem and fixing it.

From years of posts on this forum it looks like, I should:

1. Do the key-dance on-off, on-off, on and Check the Message Center MIL (Malfunction Indicator Light) for DTC (Diagnostic Trouble Codes).

2. Check the battery, and check the battery under load by turning on all the accessories measuring voltage at the battery terminals. Less than 9.6 volts would indicate a bad battery and that it should be replaced.

3. Check the voltage drop across all components from the positive terminal and from the negative terminal for shorts or higher than expected drops. ( I am not sure of how to do this, I have obtained a DVOM with alligator clips)

4. Check the fusable links (again I am not sure how to do this, pierce the wiring harness wires?)

5. Possibly check for a fusebox problem (I don't see any obvious fuses related directly to the ignition system).

6. Possibly check the ignition switch on the steering column (how would you do this?)

7. disconnect the MAP sensor, disconnect the coollant sensor - attempt to start the engine relying on the SMEC (single module engine controller) limp home mode to reconfigure the engine such that it estimates air/fuel mixtures and fires the engine even if the sensors are not reporting?

8. test the fuel pump or replace it and the fuel filter, by dropping the fuel tank and inspecting the fuel lines

9. test or replace the twin fuel injectors inside the top of the throttle body (not sure how to do this)

A. consider replacing the SMEC behind the battery on the front Left Fender with an after market OEM, or find one NOS if possible.

This vehicle was my Dad's truck. He passed away in 2009 and it just feels right to keep it going.

I do know it also has a security alarm system on the vehicle. I do not know what make or model the alarm is, or how it is wired into the electrical system.

One possibility is that the security alarm system might include a cut-off switch and could be cutting power to the fuel pump. The OEM manuals do not mention an OEM security alarm option, so I assume it was installed after the vehicle was purchased in California. Since the alarm isn't going off all of the time.. I am guessing the behavior might be it was once tripped and needs to be reset in some manner after its been tripped.. but I could be over thinking the issue.

I think I'd like to remove the security system to eliminate this possibility, or at least figure out how its wired into the system. Other than wire tracing I'm not sure how to go about doing this.

Any advise or recommendations anyone could make, would really be great.

Thanks
 

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Sounds like lack of fuel. ... Can you hear fuel pump when key is first turned on?
... Use small flashlight and look into throttle body at both injectors, they should be spraying while cranking/turning over/starting engine.
 

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test probing computer - finding factory maintainance manuals (faxonautoliterature.com) - look up codes in book. avoid either very hard on pistons. hook test probe into first the power wire to distributer then the negative once with the starter turning (you will need a hand with that one) then with it in the key on position. if your power either way discontinues hot wire either the positive or ground where it looses power to the coil without cutting up wires. perhaps a coil issue if power gets there and the ground is unhindered. if carberated check or replace ballast resister on firewall. but i think yours is like mine with the fuel body injection. not familier momentarily how the coil is hooked in.

fuel wise could be if your getting enough presure from your fuel pump where ever thats located. and knowing if and when power is getting there. you can in some cases put a pressure gauge in the fuel line. some pressure will tell you if its trying in either starting or on possition. however if your not getting 60 or 70 psi for a fuel injected vehicle you already learned that you either not getting power or if low pressure a pump thats wore out. learning which wire is the possitive on the pump can tell you where you can sub in temporary power or temporary ground wire. where wire connectors are you can sometimes find guys either specializing in wire connectors or find a set of connectors at a wrecker to use as a hot wire tester. if doing such find the ground circut and try making sure you have a ground first. do not ground your positive wire as that can cause wiring issues. with connector separated you can often pick off the power wire with a tester lights up. if neither check wiring diagrams in things like factory manuals. other weird things as inexpensive as they are is the switch on the lower steering column in the dash to replace them. I have in the past pulled them out when i suspected one and carefully taken a switch a part and slipped one back together as a temporary fix (note temporary) under dash on top of column just a little above the brake pedal. if you get spark in cranking over but the power does not continue in the positive coil wire cercuit while in the on position you may find your problem. one way to find the wire going to the coil is to find a wire off the switch that is on when cranking but not when left in on position. it will likely clue you in if that's an ignition switch. if its doing the same with with the coil wiring you could have a clue. sometimes also if factory wiring has been tampered with by adding auto starters and things of that nature you can find situations where wiring needs to be returned to original condition or order and unit removed. word to the wise never add something that tampers or adds to factory wiring. all additions should always stay completely separated from factory wiring. im not a fan of the crap that goes on doing damage to factory wires. you find guys will do that often with the steering column wires. i removed such a device off my wiring as to prevent the kinds of problems they often create. Anyways just to give ya a few clues. i could talk proper wiring proceedure soldering all joints vs. troublesome crimp connections. im fussy enough someone have to watch me doing such things. heat shrink, solder and quality crimping tools. its a game of fidget but saves car fires and troublesome joinery ensuring a perfect joint that has no choice than to have permanent lasting connection. if you crimp take off the plastic off the connectors and solder each joint. or twist the wires around each other. however im talking learned skills that often are not taught to people doing vehicle electrical work. Have fun and hopefully some luck. if wires under dash have been messed with inspect them carefully and return any wires to their original configuration. especially if they been cut to be configured to some device. Never ever ever do such to original wires. however check the column coil and fuel pump wiring for power and ground first before disconnecting any devices.
 

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Discussion Starter #4 (Edited)
Thanks! key99

Sitting in the Cab, by myself, I couldn't really hear anything over the sounds of the starter and the engine rolling over.

I'll try real hard to find a remote starter tool for the next trip, or see if I can find someone to help.

I think the tank is plastic and located underneath on the drivers side just behind the seat, if I lean out the Cab door I might be able to hear it. Or find one of those long shop ball and pin stethoscopes.

Same thing with the penlight, I'll have to find a remote start tool that works on a D250, or get some help.

Really good tests to perform, but I'm pretty much a one man show.
 

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Discussion Starter #5
cadillackid

An interesting tour. I'm on the same page with you most of the time.

The manuals I have include the electrical wiring diagrams and I've spent this Sunday watching a few Youtube videos about how to read them and how to trace problems.

Doing so by no means makes me an expert, but the exercise built confidence.

I saw or read one interesting concept that broadened my thinking.

A guy was suprised that a bad Coolant sensor could shutdown his ECU (Electronic Control Unit) and allow him to turn the engine over but not start.

After he resolved the problem by replacing the sensor, a commenter to his video blog pointed out [any] sensor on the 5+ volt bus or the 12+ volt bus of the SMEC or any computer, could be shorted to ground.. and in doing so cause the SMEC to fail safe and refuse to start because so many sensors were offline, they all need a certain amount of power, or because the computer needed that power to keep itself running.

The EFI/TBI combo is still essentially a Carburetor with an Ignition switch a Distributor and a Starter motor. The Computer simply manages the relays and performs the role of the Points in the distributor electronically. A No start could be very similar to a failure of the Breaker points in a Distributor, but for more "Sensor" related reasons.

And thinking about it, even a DRB-II (Diagnostic Readout Box) wouldn't do much good if the computer were totally unable to start due to a short. So I guess striping the problem set down by disconnecting or replacing sensors is the cheapest, swiftest approach.. fewer points of possible failure.. after its started and the computer is running on "theorectical" operating curves in its memory.. adding back the sensors sounds like a good way, to bring it back into alignment with reality... and bring back its performance.

Thanks for the suggestions to keep it simple and clean and not mess with the integrity of the wiring. I'm a firm believer in that. But I also know you can't do much about whats already been done, except restore it as it seems possible while troubleshooting.

Its difficult to focus on a straight and narrow troubleshooting path, when there are so many things pandering for attention.

I'll be happy to share whatever happens with the forum.

I always wonder what happened to the posts that seem to never conclude.

Thanks
 

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Discussion Starter #6
Most recent trip

Back from the Holidays and a trip where I could take another look.

The car alarm is called "Pursuit 2033 D" its a black box and that is about all I know about it.

I did notice another Relay hanging from under the center of the Dash which looked exactly like the (Fuel Pump Relay)/(Auto Shutdown Relay) under the hood on the driver side fender.

And the battery is over 4 years old, so I suspect it has Sulphanated Crystal damage from all the Hot/Cold Summer Cycles and being deep drained for so long.

I plan to replace the battery and possibly come up with a "by-pass" block to put in place of the Relay from under the dash. I strongly suspect it is a fuel pump disabler and that the alarm system had been tripped at some point in the past or just never reset after the battery was drained and recharged.

I've read several accounts that the car alarm not being reset would result in the alarm "appearing" to be working, but still having disabled the fuel pump until it has been reset.

I "think" AudioVox bought the name for the "Pursuit" car alarms years ago, but this one would have been installed back in 1989 or shortly after so it is so old I doubt "anyone" has any documentation or recollection of how it works.

Thanks for all the advise.

I'll post some pictures when I get a chance.
 

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Discussion Starter #7
AudioVox Support Identified the Alarm System

I was really surprised when I filed a support request with AudioVox


I attached pictures of the Alarm system, and they were able to look at the circuit board and determine the model number.

They followed up by sending me a PDF of the Installers Guide and the Owners Manual.

And they suggested based on my inability to start the vehicle that it was probably not related to this model alarm, because it does not cut the fuel pump but instead cuts the start solenoid low current activation circuit.
 

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Have you located the fuel pump relay? Put a finger or two on it and turn the key to "On". You should feel it click. It may be burned out or not getting power for some reason.

Does this model truck have a safety switch that shuts down the fuel pump when there is no oil pressure? I blew up an engine once a long time ago when I hot-wired an electric fuel pump to a car with a bad oil pump (didn't know that at the time though). It turned out that the light bulb in the oil pressure idiot light was missing and the safety switch was preventing the car from starting. I bypassed everything and wired the pump to key-on battery power and drove off. For about 15 miles everything was fine, then lots of tappet noise quickly followed by a connecting rod on the ground under my car and a new inspection window in the block.
 

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Discussion Starter #10
Have you located the fuel pump relay? Put a finger or two on it and turn the key to "On". You should feel it click. It may be burned out or not getting power for some reason.

Does this model truck have a safety switch that shuts down the fuel pump when there is no oil pressure? I blew up an engine once a long time ago when I hot-wired an electric fuel pump to a car with a bad oil pump (didn't know that at the time though). It turned out that the light bulb in the oil pressure idiot light was missing and the safety switch was preventing the car from starting. I bypassed everything and wired the pump to key-on battery power and drove off. For about 15 miles everything was fine, then lots of tappet noise quickly followed by a connecting rod on the ground under my car and a new inspection window in the block.
I have located the fuel pump relay, but I can't think of a way of keeping my finger on it while reaching inside the cab of the truck to turn the ignition key on. But it does pose an interesting mental picture.

I don't know about an oil pressure safety switch. But I do have the Dodge Service manuals. It is something I can study up on. Its also an interesting thing to look into.

Overall I'm taking this project slow and giving it lots of thought between each move. This trip I removed the battery and plan to buy another and turn this one in for recycling.

I tend to think a lot of my attempts so far are hard to be confident in since the battery is over 4.5 years old, it has been drained completely and left sitting in the vehicle through several seasons of very hot and cold weather.

After studying Lead Acid auto batteries, I've come to understand this is the "worst case" scenario for managing an auto battery and the quickest path to killing it or vastly reducing its lifespan. So there are multiple reasons to believe, even though it did take a charge, that one or more cells in the battery were simply beyond hope of being fully functional. That the engine cranked at all should be thought to be amazing. That it fired when gas was sprayed in the throttle body also amazing.

Since the engine never actually transitioned to a fully running condition, the battery was literally all that was funding every spark that burned fuel. The alternator probably had no chance of sustaining the firing, let alone charging or maintaining the run and recharging the battery at a reduced capacity.

I've just come to believe I was wishing for too much from such an old and poorly treated auto battery. So I think I have to address that problem first.

Thank you for your suggestions. I will study them and heed their warnings.

I'm a bit like a Deer caught in the headlights of this problem because there is so much I do not understand or know about working on an engine. So I feel I must pay attention to every suggestion, however so small.

Thanks!
 

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Roll down window: "listen" as you turn key to ON position (DO NOT CRANK or start), IIRC fuel pump should run a bit.
 

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Discussion Starter #12
Its still raining quite a bit. The season is changing from Winter to Spring.

But I made the trip again and installed the new battery and tried listening for a sound from the fuel pump.

Its hard to be certain but I thought I heard a "clunk" each time that I turned the key to run but didn't crank.

A few cranks and still no start up.

Poured a very tiny amount of fuel into the throttle body and got what sounded like a single normal fire and then it just cranked.

I've been very cautious about disconnecting the fuel line from the throttle body, because I thought it would be pressurized (the engine is EFI). So I disconnected and removed the battery from the engine compartment and then covered the connection with a rag and disconnected it.. it was not pressurized and dry.

I traced the fuel line back down to the frame and to the inline fuel filter.

I disconnected the side labeled "out" headed towards the engine and it was dry.

I disconnected the side with no label headed towards the fuel tank and it was not pressurized but dribbled fuel.

Neither side of the fuel filter was under any pressure at all.

Finally I put the battery back into the engine compartment and tried to actuate the fuel pump.. again I thought I heard a "clunk" like a small relay throwing.. almost a "click" and then nothing.

I don't know what to expect, but I would assume a whirr or a small motor sound as opposed to a "clunk" or "click".

With the fuel line disconnected from the fuel filter I would have thought to see a spray of fuel or something.. but absolutely nothing was forced out.

That leaves me thinking its either the fuel pump or the electrical feed to the fuel pump.

Since the wiring harness conceals the wires to the fuel pump inside of some black wrappings. I'm not sure of how to test the electrical feed.

I'm now leaning towards replacing the fuel pump.

I did check the fuse box under the steering column and the wiring diagrams in the service manual. It doesn't appear there are any fuses that feed the fuel pump. There is the ASD - Auto Shutdown Relay, which I did replace in case that was bad, but it made no difference. I do hear the ASD clicking quite clearly and distinctly in the engine compartment when I turn the key to run.

I also performed the key-dance to check for Diagnostic Codes, but it only returned 12-55 which I believe means "battery disconnected within last 50 starts"; followed by; "end of diagnostic codes" - so it doesn't give me any fault codes to work backwards from to find a cause. I'm hoping that is a good thing.

Reading up on in-tank fuel pumps for a number of vehicles it seems they are prone to burn out if they are starved of fuel for a short period of time. Some people advised never allowing the fuel gauge to drop below 1/4 tank to avoid even the remote possibility of accidentally running the fuel pump for any length of time without fuel to cool it. I have reason to believe it has in fact been cranked several times without fuel before refilling it.. so that is a possibility.
 

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Prime it again with a tad more fuel this time; it should fire more than once, maybe run for a sec or two.

Yeh, not at all good to run pump with no fuel; and avoid letting tank get low as mentioned.
 

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jwillis84

I have not quite done a full read on you. My own truck has been a russian roulette spin of the gun to see where the bullit comes out. I am having major issues with spluttering not getting spark etc. started with a coil and i got away a month or two then it reoccured with the loss of spark problem then changed 3 distributor parts then the map sensor then crank and cam sensors, had all the engine compartment wiring checked over.

I am not sure where to spin the bottle next. Perhaps that black box by the battery who knows what that idiotic thing does. or changing the computer or hotwiring the power or ground going to the computer. I have killed 2500 in frustration knowing i would have been money ahead to have pulled the motor when i bought the truck. 5 grand is the wrong answer to trying to achieve a reliable truck. its had me thinking seriously about never going with a fuel injected vehicle again. this one has truely been a nightmare and left me stranded 3 or 4 times and not wanting to take it out anywhere without having someone follow me with a tow rope. reading on another forum these trucks are notorious for multiple problems. as for your hoping that I might be closer to know how to diagnose the thing and after turning it over to a shop to go over I am not sure I am any further ahead. If someone could tell me the thing would run with a change to an older style distributor. i would rip the thing out and all its BS and poor designing in a heartbeat. I am where you are at not coming any closer to the actual problem and the computer leaves no clues other than to throw parts at it in hopes to find the offending piece of Crap. However have you taken a test meter to the power wire on the coil input wire. if no power there when it dies your more likely looking at several things. I am about to price out the computer next. having rebuilt the transmission and 2000 diagnosing and replacing parts on the engine. honestly, i will pull it the next time. Transmissions are too costly to rebuild and engines too notorious for electrical issues. Had it to do over again the engine would have got sold off and in with an older powertrain carberator 727 transmission and all. I have done this transmission twice. not a reliable combination. and definitely not a truck i would trust on a trip. However i will let you know if i cure things with replacing the computer and the cost on the thing hoping only a couple of hundred dollars and hopefully the cure. they are definately one of those things even good mechanics have issues trying to diagnose. I had a whole shop of people puzzling over the thing and half of the electrical pulled out and replaced already. some may not agree with my recommendation but pull the powertrain. they are bad news and very expensive. one of my questions has been can the block be saved with a change of cams heads and intake.

I puzzle just like you and not wanting to kill a fortune more on the truck. ready to start back in on my 82 Chevy which has been a full redesign and me strategically trying to bring that engine back to simplicity. with both the carb and distributor fully independent of each other. when i have issues i prefer to go to exactly one item and have it licked and back down the road in short order. However seriously wish i had a better answer for you. or vica versa. however ill let you contact me direct fella if you should happen to come by an answer for your own delema.

fuel can be tested with a pressure tester useually something like 70psi
then spark check that first with the power lead before the power gets to the coil.
if both seem to be periodically wonky when she dies try a computer.
also test in periods when it seems to run good.

Id like to find a small course in doing some of the electronic work and some how step by step trace it all through. I think the shop i took it to did every thing short of taking it for a drive and trying to leave themselves stranded with the thing. my plan of attack is the computer next. maybe should have been my first plan of attack. I'll try and give you a more thorough read. perhaps see if anything your trying is triggering anything in my brain. My brain has already said no more fuel injected vehicles after two i want no more.
:wzup:
 

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Direct quote on something earlier. has me thinking of probing some heads for answers on this possibility. its also been seemingly a cooler running engine this last winter. and pondered also changing the thermostat.

ill put that one on my list.


((((((((((((A guy was suprised that a bad Coolant sensor could shutdown his ECU (Electronic Control Unit) and allow him to turn the engine over but not start.

After he resolved the problem by replacing the sensor, a commenter to his video blog pointed out [any] sensor on the 5+ volt bus or the 12+ volt bus of the SMEC or any computer, could be shorted to ground.. and in doing so cause the SMEC to fail safe and refuse to start because so many sensors were offline, they all need a certain amount of power, or because the computer needed that power to keep itself running.

The EFI/TBI combo is still essentially a Carburetor with an Ignition switch a Distributor and a Starter motor. The Computer simply manages the relays and performs the role of the Points in the distributor electronically. A No start could be very similar to a failure of the Breaker points in a Distributor, but for more "Sensor" related reasons.)))))))))))))
 

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Willis...
hmmm saw your battery convo. Batteries are notorious for causing issues. from shorted cells to corrosion on the battery terminals. grounding or contact issues can cause a hose of problems.

clean both battery and posts and clamps with baking soda mostly in a tub outside of the truck however if acid is on the battery box douse it as well.

often you end up with power travelling the acid between the poles or poor continuity at the terminal. however do check condition of wiring at the clamps. if worn or damaged repair these things. when all is cleaned with the baking soda water mix and put back together. take Vaseline (petroleum jelly) and coat the clamps. as the battery charges itself it will pull the jelly around the surface leaving and keeping the posts and clamps corrosion free.

many issues are caused with lack of continuity around batteries. one of the big issues is the fusable link wire coming from the battery. id take ya a photo however its a bit of a description how to repair one. however when you do use the same gauge and soldered joints when installing. Demonstrating proper wiring procedure and twisting wires together possibly take some description but dodge was notorious for this little wire problem coming out of the 70s. however link should be put in identical length of unsoldered wire and same gauge thickness.

Another thing on batteries. open the caps and top up till water touches the bottom of the holes. Note use distilled water NOT purified. An oddity however is that many house furnaces condensate and drain off distilled water.

A quarter when you have a alternator kicking out will pull harder on a quarter off its back than when its not producing power (magnetism) I have not dealt with alternator wiring like i dealt with with the 84 dodge which required me to beef the wiring after tracing back burnt wires off the alternator. however both problems with that and the fusible link are solved by good grounding and continuity of the battery. Another area one could look at perhaps for drops in power that kill and engine. I redid my fusible link recently. if i should find a photo of the rebuilt wire piece perhaps i can give you a few clues how to properly build it to last as it is a common fix. this is something you seriously do not want to just crimp connect and wrap in tape.

Often these fusible link wires will have spots where you will have to follow wires back to replace wire that's shown heat damage. often the result of poor joinery or installation of Link wires. Wires that have shown heat damage should be replaced or sectioned out. Just case this offers any possible solution to you but definitely preventative maintenance.

Carman [email protected]
 

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Forgot to mention... the chemistry of baking soda neutralizes the acid on the outside of the battery to a non acid thus also cleaning it. the Vaseline is like keeping a battery from being able to corrode and hinder continuity around the posts and ends of the cables. however never use grease as grease hinders continuity and causes wiring issues. however the Vaseline coats but leaves the maximum amount of potential continuity as well as protects it.
 

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Discussion Starter #18
Battery advise

cadillackid thanks for all of that.

I'm sorry to hear your having similar problems with an EFI equipped system.

My Dad's truck is in a fairly stable location and it is not my primary vehicle, so its a "nice to have" thing not a "must have" thing.

I wouldn't say I've enjoyed the problems.. but its been very educational.. and what I learn I've been able to apply to my current primary vehicle. My current vehicle has fuel injection since that is the norm on vehicles today and it has an in tank fuel pump.

The 1989 Dodge D250 was one of the "first" EFI vehicles so its much simpler than the MultiPort Fuel Injected vehicles of today.

In a nutshell the EFI on the D250 truck has a pressurized fuel line from the tank to the external inline fuel filter mounted on the undercarrige frame, to the throttle body (which replaced the carbeurator on older vehicles). The pressurized fuel is then allowed to "squirt" into the throttle venturi (the throat) and atomizes before it primes the cyclinders and is ignited. An overpressure regulator makes sure that the fuel pressure to the "injectors" inside the throttle body are not overpowered and held open or closed, but held at just the right pressure for the injector solenoids to open and close reliably. The "over pressure" is releaved by diverting the extra fuel through a return line back into the fuel tank. So the fuel system is a "closed loop" pressurized going to the engine and pressurized coming back from the engine.

The fuel pump is supposed to maintain a pressure to the injectors even when the vehicle has been sitting and not running for hours or days.. so its ready to start without waiting for the fuel pump to spinup and prime the fuel line.

What I found was the fuel line was not pressurized and was not being pressurized while cranking the engine.

So that told me there is either no electriticity powering up the fuel pump, or the fuel pump has mechanically failed. I suspect the fuel pump has mechanically failed.

I can't really test the electrical connections to the fuel pump without dropping the tank to get access to the fuel pump electical connectors.. so that is the next step. If they are fine and providing voltage. I will proceed to pull the fuel pump assembly and replace the pump and in take fuel hose.

I've been studying the procedure and it doesn't look too bad. I need a couple jack stands to raise the vehicle, and I'll need to drain the tank, then use a floor jack and block of wood to ease the tank down, to access the pump assembly connectors and disconnect them.

I'll then have to remove the tank and clean it out, replace the pump, reassemble and concurrently replace the inline fuel filter on the undercarriage frame.

After all that I should be able to pressurize the fuel lines with the ignition switch and check for leaks.

Hopefully that will put an end to my problems.

The more I've read about fuel pumps and clean fuel lines, and the rule of never allowing the pump to be exposed to low fuel in the tank.. the more I've come to appreciate that taking the time to keep a full tank of fuel is "very" important.. and that fuel pumps go bad almost as often as catalytic converters for very minor lack of maintenance and regular changing of the fuel line filter.

Its also a major problem that all the new gas station fuel mixes corrode and erode the formerly acceptable rubber in the fuel line interconnects.. so the older vehicles literally "fall apart" because at the time the vehicle was built OEM rubber was never designed to handle the horribly acidic fuels of today. When they disintegrate the rubber particles travel the close-loop fuel lines and eventually burn out the fuel pump.. the fuel filters only delay the situation. So the fuel pump and lines have become regular "consumables" when performing maintenance.. far less than the life time of the vehicle.. more like 3-5 years instead of 10-20 years.

The replacing of the breaker points with the ecu (electronic control unit "computer") does add a lot of complexity. But the situation is what it is.. working the problem, if yours can run in a "theory mode" with all of the sensors disconnected.. that might be one way to diagnose your problem.. by successfully starting in "theory mode" with no sensors attached.. then reconnecting one at a time until it stops starting or reliably running.

Another thing I'm becoming aware of is a bad catalytic converter.. which is like a "filter" for the exhaust that "always" gets clogged.. needs to be changed. If it is not changed the "back pressure" will cause the engine to stall, or at the very least to run very poorly and with very poor gas mileage. It can make the vehicle appear to have all kinds of transmission or fuel, spark problems.. but its just a simple filter problem. -- I am not even running yet.. so I know that's not my problem.

In years past a catalytric converter could cost $400 to $1200 easy.. but with a choice between EPA or CARB versions it can be ten times cheaper. The labor can still be expensive.. but I think if you need one its better to know that than spend a lot of time on other things that are not causing the problem.

I read simply removing the O2 sensor to allow the back pressure to exhaust "temporarily for a test" is a good way to quickly see if your problems are related to the catalytic converter.. just don't drive it that way!
 

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not sure what the complete stats were on your engine other than being the same block with a different bore. catalytic is gone off of mine when i did the exhaust. however noticed that you had the 360 where i had the 318. in the 318s at least you found the same setup from 88 to 93 and i think it was either 94 or 95 when they made a change up. non the less very expensive power trains for repairs and too unreliable for me. I had never anticipated 10 moduals or whatever before an engine can get reliable spark which is crazy. I have almost been ready to carve the problematic equipment out of the truck but hoping something works so i can sell it off.

you may consider looking for things like fuel strainers while you have the tank down. or broken wires. I have almost been ready to carve the problematic equipment out of the truck but hoping something works so i can sell it off. i hope your closer to ruling out your issue. im aiming towards the computer myself and hot wiring the power and ground to the thing if that's possible. if i had known what i was up against i would never have bought the thing. I had bought it with a blown transmission for 600$ realizing now that i should have pulled the engine and installed something with a carb. non the less these trucks in these years are off my list for future buys otherwise.
 

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Discussion Starter #20 (Edited)
Just an Update

I'm still waiting for the weather to settle down, its been a windy and stormy Spring across the state. Seems like almost every weekend is raining or predicted to rain until May. Temperatures are warming up though.

After acquiring two 3 ton jack stands, total capacity 6 tons. I also acquired a 3 ton floor jack and studied lift points. It seems after chocking the wheels good, lifting by the axle gearbox is the norm and then supporting the axle with the jack stands.

I came across a Canadian Safety guide about Lifts that indicated torque from a breaker bar could be hazardous and it went on to more or less explain that Impact wrenches are less likely to destablize a vehicle while its lifted. They suggested loosing and breaking tight bolts before lifting a vehicle if at all possible.

Also ran across an optional crossmember that you can get to mount on a floor jack that has a hex nut under its lifting pad. The crossbeam then extends outwards in both directions to provide two equidistant lifting pads to better balance, supporting a long load. Not all floor jacks have a hex nut under the lifting pad, less expensive ones have a permenant bolt or rivet.

And I saw there is such a thing as a transmission lift accessory for floor jacks, that mount in the same place to repurpose a floor jack as a transmission lift.. way outside my league. But interesting.

For lowering the fuel tank I have a few options once the vehicle is lifted and supported. I can use the floor jack as it is and place a 2x6 or other size block of wood between the lift point and the body of the fuel tank (to prevent punching a hole in it with a single lift point). I can use lashing straps with buckles to tie the tank to the surrounding frame and lower it slowly after the support straps are loosened. Or attempt to only partially lower it and work with it hanging (don't think this will be possible since it probably needs cleaning).

Regardless the fuel lines and filler tube have to be removed while its still partially in place. The fuel lines are attached to right angle plastic connectors on the fuel module.. and people have a terrible time breaking them and end up having to replace the entire module. Unfortunately the 1989 D250 fuel module seems no longer available OEM or NOS and even in junk yards because of the Ethanol in our fuel supply tends to be damaged by rusting in moisture in most fuel tanks these days.

Airtex has an "excellent" YouTube video with Richard Young showing and demonstrating the [many] fuel line connectors and how to recognize them and release them. Its amazing how many there are and how many require a special tool to release. There are tool kits just for releasing "pinch" type fuel connectors. Most are wedged on severely by time and dirt and are likely to jam or be hard to remove. Fortunately for me it looks like the older the vehicle the simpler the the pinch type of connector.. you just have to know the trick of how to get at the edges and where to apply pressure.. and "most" important [ understand ] the connector separates from an inner piece once its released and that part stays on the plastic fitting on the fuel module and the other part comes away in the fuel line.. that is the connector turns into two pieces when its properly removed.

There are also a couple videos regarding the safety valve in the filler tube most vehicles have which obstructs siphoning fuel from the tank.. almost comically many people recommend by-passing the fuel relay to "pump" the fuel out of the tank using the fuel pump.. or driving the vehicle around to empty the tank. .. but.. we're dropping the tank to replace the pump.. because.. it doesn't work. Some of the better siphon kits have a flap holder, a stiff guide hose to get around the valve, and a siphon tube that fits inside the guide tube to actually siphon the fuel.. and have a neoprene bulb to start the flow of fuel without having to risk inhaling fuel to get it started flowing.

While I'm waiting for the weather to improve.

I took a detour down ODB-I scanner tools for Electronic Fuel Injected vehicles with computer controlled Electronic Ignition.

Dodge/Chrysler had a Data Readout Box called DRB-II for connecting to the computer "network" under the hood. In the 1989 D250 the network seemed to consist of only one computer, the SMEC.. other vehicles and later vehicles would get a transmission computer, body computers for airbag control and brake computers for traction control. The engine computer reads several sensors and makes decisions about how to set the throttle, when to open the fuel injector solenoids or enable disable the transmission torque lockout. The DRB-II box can connect to the network and listen into the conversation, communicate with the computer and help diagnose whats going on.

Apparently made by the OTC tool company the DRB-II had a retail cousin called the OTC4000E which could do many of the same things. These were very expensive new, but now only occasionally available used on ebay they seem useful things to have to help understand what going on with a EFI backed engine.

In addition to being communicators and message display monitors. They could log data, connect to a PC with a seperate serial port specifically for PC communications. And they could be used as Digital Volt Ohm meters. A PC running data logging or graphing software like the GTi Graphing Software from OTC for their OTC4000E could enhance the capabilities further. Dodge/Chrysler had their own system for the DRB-II which might be similar or completely different. There seems less information generally available for the DRB-II even though it looks very similar to a OTC4000E

So I'm looking at acquiring one or two of these at low cost and learning how to use them.
 
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