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Discussion Starter #1
Hey Guys,

I recently bought an 01 ram 1500 4x4. It's got the 5.2L, automatic, with only 55k. I bought if from a dealer on the east coast, and had it shipped to texas.

As soon as i got it, it started missing, backfiring, and trying to die when i drive it in town. When i stomp the accelerator, it will clear up slightly, but it doesn't crank up well, and it doesn't idle well. I've replaced: Cap, rotor, plugs, wires, fuel pump, oil, filter, air filter, muffler, cat, and O2 sensors. There are no codes in the computer. When i drive it down the road, it mostly clears up. It seems to be the worst during stop and go driving, with lots of starting and stopping of the engine?

Any ideas / suggestions?
 

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I worked on one a couple of years ago that had a coil wire with high resistance. The extra resistance overheated the ignition coil. The epoxy like potting material cracked/split open on the bottom of the coil. The truck would still run but backfire and spit at random. New Ign. coil solved the issue.
 

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Discussion Starter #3
I considered a new coil, but wouldn't the coil get hotter, the longer i drive? I drove it last night, on a 60 mile stretch to another town. It ran perfectly on the road, and into town. I killed it during dinner, and when i came out, i had the same sputtering issues. Once i got back on the road for the return trip, it smoothed back out, and ran great the the 1 hr trip back. THis morning, i had the same sputtering, and hard start problem.

I'm not arguing, but wouldnt the coil generally work well cold, but get worse hot?
 

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Yes, I agree with you on the fact that coils typically break down when hot, or are bad all together. Possibly you have moisture in the distributor that condenses on the pick up coil then dissipates after the rotor spins. Even then I wouldn’t think it would act up in the length of time it takes to eat dinner. I have seen crankshaft sensors cause hard starting and stalling on later model trucks like the 3.7L,4.7L&5.7L(engine mounted). But I have never experienced that kind of problem with your model (sensor mounted in transmission bell housing) but anything is possible.
 

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Discussion Starter #5
Any idea what a new crank sensor runs? I've replaced one on an older Powerstroke, but i've never experianced any trouble with them on gas engines.

I hate to simply replace random parts, without knowing for sure that they are faulty. I've also heard the suggestion that i may have a vaccum leak, but surely it would act up on a longer drive as well.

The sputtering is almost constant today. It's hard to drive at all in town. It hasn't run smoothly in at least 7-10 short trips, regardless of operating temperature.
 

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Mopar Part # for the crank sensor is 56027870 E. You can check the retail price at several online dealers that have parts pricing on their website (Example Bill Kay). The thing that bothers me is that you don't have any fault codes. The controller looks at the signal from the crankshaft sensor/tone wheel. It distinguishes a drop in crankshaft speed and can narrow it down to a specific weak/misfiring or dead cylinder. So normally a misfire fault is set if the problem occurs several times over a set time frame. Or if the crankshaft sensor is failing it often puts out an erratic signal that the controller can't interpret. This typically also sets a fault code.
Most vacuum leaks give you a high idle because it's leaning out the mixture. Or they can give you high oil consumption and spark knock if the leak is internal(as in the valley pan gasket that the 3.9 5.2 5.9L have).
 

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Discussion Starter #7
I'm definately not running lean. It seems to be getting way too much fuel, while it is sputtering, etc. There's a distinct hissing from the air box, and i get some black smoke and fuel odor when i crank it up. Again, it doesn't happen every time i start the engine, but for the past few days, it's been at least 80% of the time. I've had it at a local mechanic, and his scanner doesn't show any problems.

I manually checked my fuel pressure at the rail, and I have a consistant 50 lbs, whether it is ideling rough, or smooth.
 

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Did your mechanic watch the O2 signal while the truck was running rough? If it is running rich the upstream O2 should be indicating a rich condition. At that point you would have to pinpoint if a particular cylinder is making it rich or if long term fuel adaptation has the fuel cranked up due to a bad O2 signal. Long term fuel adaptation can be looked at in the OBD section of the scan tool. If the controller shows that is adding more than say 10% fuel above the base calibration then the O2 system must be out of spec. If long term adaptation is pulling fuel out from the base calibration and it still rich than you may have a sticking fuel injector. This is to say that one or more injectors are always slightly open spraying fuel even with the intake valve closed. So when the affected valve opens extra fuel is drawn in and misfires. A leaking injector will also allow the fuel rail to loose pressure quickly after shut down. This causes a moment of hard startup until pressure is back up to spec. You can check for leaking injector with your fuel pressure gage. Hook it up to the fuel rail, start the engine until fuel pressure stabilizes. Then shut the truck off and watch the gage. If pressure drops rapidly an injector is open. Ideally the pressure should hold stable overnight if everything is good.
 

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Discussion Starter #9
We may have just fixed the issue. We simply cleaned the throttle body with B-12 carb cleaner, while the truck was running. We sprayed the at idle air control motor, map sensor, and into the throttle body. It seemed to run better immediately, and has run well for about 8-10 miles. Keeping my fingers crossed. If this doesn't fix it, i'll try your last suggestion.

Thanks for your help thus far.

Any idea on the best way to sea-foam this engine? Any pros / cons about using sea-foam?

Thanks again.
 

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Discussion Starter #10
Ok,

I definately have dropping fuel pressure. After killing the engine, i lose about 20 lbs in 10-15 minutes. This would seem to jive with the hard start, after about 1 hr of sitting. We ran injector cleaner right into the fuel rail, to see if maybe the injectors are just gummed up. This seemed to help while driving, but we are still losing fuel pressure.

Any idea as to how to isolate the leaking injector(s)?
 

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Shop safety: It’s always a good idea to have a fire extinguisher nearby when working on the fuel system!!
The easiest way (thought probably not the safest) is to unbolt the fuel rail and lift the whole fuel rail/injector assembly up. Start with a cold engine to avoid possible unwanted ignition sources. Be sure to blow out any sand & grime build up that has formed around the base of the injectors so it doesn’t fall into the intake when they are removed. On the 3.2/5.2/5.9L the press fit of the injector o-ring into the intake is fairly high. So you will need to coax each injector gently taking your time in an attempt to get them to all back out at once. If you pull to hard the injectors may pop out of the spring clips that hold them to the fuel rail. You don’t want that to happen if possible to avoid having a large amount of fuel dumped on top of the engine. Once you have the rail asmy. lifted up verify that all of the injectors are indeed firmly snapped into the spring clips. Next prop the rail up high enough where you can slide a paper material underneath the tips of the injectors. Preferably use something metallic like screwdrivers or socket extensions that will ground the injector rail to the intake to minimize risk of static sparks. Next turn on the ignition switch (do not crank engine over unless you really don’t like your truck anymore) so that the fuel pump will cycle. Now turn off the ign. and observe the injectors. I like using thin cardboard like from a cereal box under the tips. The cardboard absorbs even trace amounts of fuel leaving a nice wet spot that indicates the leaking injector.
I must mention that I have run across a bad check valve in a fuel pump years ago. I checked all of the injectors and found nothing, so I then deadheaded the fuel line at the cowl. The pressure dropped off in a couple of minutes, indicating that the pump had a problem with its internal check valve. I know you have already replaced the pump so hopefully it’s good.
 

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real quick, are your sparkplug wires routed according to Chrysler's diagram? its somewhere on here i know, but dont have time to search. also change the cap and rotor.
 

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Discussion Starter #13
CMH2007:
I'm not sure if my wires are routed as per spec. I'll have to find the diagram and check it. I just replaced my cap and rotor.

HEMIMECH:
Tried your instructions to find the leaking injector. There is one that is visably dripping. I'll leave it on cardboard overnight, to see if any of the others are slowly leaking.

Any brand suggestions on the injectors? Can I replace just the leaking injectors, or do I have to do all 8?

I really appreciate your help thus far. I think we may finally have a sollution.
 

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Discussion Starter #15
I replaced the leaking injector, and my IAC. Now it cranks well, and idles fairly well, but it still pops and backfires during city driving. It still tries to die, and doesn't have any power while it's acting up. It ran well for a few hours after the injector swap, and then started acting up again.

I just now got a check engine light to come up for the first time, so i'll have my mechanic check it tomorrow.

So far I've replaced:
Cap; Rotor; Wires; Plugs; Idle Air Control; Leaking Fuel Injector; Fuel Pump; Cat; Down-Stream O2 Sensor; Muffler; Oil; Oil Filter; Air Filter; Cleaned the Throttle body with Carb. Cleaner, and Sea-Foamed it.

All i've managed to fix is the hard start, and part of the idleing problem.

I'm starting to think a jug of gas, and a match might be the best fix for this POS.
 

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what about up-stream o2 . that's the more important 02 :SPIN:
 

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Discussion Starter #17
Anyone know what the voltage range is for a good MAP Sensor? Mine is fluctuating from .5 to 4.0. I've had numerous suggestions to replace the MAP Sensor, but i'm hesitant to do so if i'm not sure that it's causing the problem.
 

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At the map sensor: Pin #1 (black/light blue)ground
pin#2 (Dark Green W/red tracer) Signal out to controller needs to be less than 1.2 volts with engine off and shouldn't exceed 4.6 with max manifold vacumm w/engine running.
Pin#3 (Purple W/white tracer) 4.5 to 5.0 volt batt + input to sensor.

Sounds like your MAP sensor is in range.

Also remember that 3.9, 5.2L, 5.9L Fuel injector timing is controlled buy the pick up coil underneath the distributer rotor. The pick up coil could be flaking out or not timed correctly. On these engines rotating the distributor doesn't change the ignition timing (that it controlled thru the crankshaft sensor) The Injector timing must be set with a scan tool like the DRBIII that can look at crank angle vs. injector event. Because you recently bought this truck who knows whos hands have tampered with it. Maybe they played with the orientation of the distributer thinking they were changing ignition timing.
 

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map sensor flucuating????????????? start looking at bad vales or broken valve springs...........been there done that.............if an intake valve is not sealing correctly, compression can and will go past the valve and up into the intake..........pcm goes for a shit as the engine"load" is changing quickly and not normal values......................a snap on solus or modis or any laptop based scan tool should be able to "graph" the map pid.................look for a steady 11(ish) inches of mercury("Hg)........an erratic line means bad sensor, bad vacuum source,or bad engine vacuum................could stick a guage on it as well..........."dancing/twitching" guage is ussually valvetrain related..............leakdown test will prove it
 

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Discussion Starter #20
I do know that the distributor has been rotated in an attempt to adjust timing. One of my buddies was trying to lend a hand when i first got the truck.

Any idea if a Snap ON Scantool has the capabilities to adjust injector timing? I have no idea what model it is.

I borrowed the Snap On scan tool this weekend. It shows cylinder # 7 to be missfiring constantly, during idle. As soon as i give it a little gas, the counter stops, but when it comes back to idle, #7 begins to missfire again. The engine responds well at wide open throttle, but tries to die during slow acceleration. Even with the engine sputtering and trying to die, #7 seems to run ok. I do get a random 2-3 missfires on any one or two of the other cylinders, during this sputtering stage. At idle, # 7 doesn't fire at all. I can take the plug wire off, and it makes no difference. I can feel the injector pulsing, and the wire has spark. The spark plug also sparks, so i'm at a loss.
 
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