93 B250 Ram Wagon Engine dying [Archive] - DodgeTalk : Dodge Car Forums, Dodge Truck Forums and Ram Forums

: 93 B250 Ram Wagon Engine dying

07-13-2011, 05:45 PM
Hello everyone! My name is hannah and I have a long question for ya'll. I want to preface this by saying that I have been searching the forums for the last three days before posting this to try and find an answer to my problem as I know this problem has afftected many dodge owners!

the van: 1993 Dodge B250 Ram Conversion Wagon
318 5.2 L 75K original miles

The history: I bought this van three months ago. It was running great, expect my husband noticed that occasionally it kinda surged on the freeway. We put a bottle of Lucas in it and the problem went away, for the most part. We took it on a 1000mile round trip, 80 miles from home it just up and died on us on the freeway. No power to the radio and when you turned the key, no crank, nothing. We sent out for a new remanufactured PCM thinking that was the problem because the previous owner's mechanic said that the PCM in it was for a dodge dakota and he'd had this problem in the past. When the new PCM came in the van still didn't start so my mechanic went through and found a short that he fixed (on the wiring harness) and then the van ran great.

Right before we took it on another trip the van died on us on a residential road. However this time when we turned the key it cranked, but didn't start right away. After about 5minutes it started up again but we decided to change the fuel filter just in case. My husband thought that it may be the fuel pump but because the previous owner said that he just installed a new fuel pump we went on our merry way. 1000 miles later the van died on us again, and this time it took about 30 minutes before it would start up again. Turning the key provided us with a crank, just no start up. We end up making it back home with no problems but had started noticing that when coming to a stop the engine started to surge and then die. I found that if I put it in neutral when coming to a stop then I could by pass the engine dying. However the other day after going to dinner with family we got in the van, put it in reverse and it died on us. Took us 30 minutes to get it to turn over again then died on us a mile down the road. It started back up in an hour and a half, just as the tow truck was showing up to tow it home and then died quickly. The next morning after getting it towed to a mechanic's shop it started up just fine then died 20 minutes later. It seemed like the engine was being flooded with gasoline even though the gas pedal was not being pushed down. The mechanic said that we need a new PCM, that the crankshaft sensor and the cam sensor/ or distributor was not getting power from the PCM. They said that they swapped out our PCM for a different one (not the correct brain, just one that 'looked like it would fit' from what they had lying around) and said that when they put those in it was getting power just fine.

I am wondering if the sensors themselves could be the cuplrit as we just received this brain not even an month ago AND we were having slightly the same problem with the old pcm and the new pcm. He said that the fuel pump was NOT the culprit and tried to assure me that it has to be the PCM. I am not a mechanic and am just learning how to work on my vehical as I am getting tired of having to pay someone else to do work on my van and it still not running properly.

I have found that it could be multiple things
*crankshaft sensor
*cam sensor
*O2 sensor
*MAP sensor

I tried to get the mechanic to go step by step through what he did to KNOW it's the PCM but I don't know him from adam. My MIL ensures me that this guy is trustworthy but I am not too sure. I know this is long and I've tried to include everything to help ya'll help my diagnose the problem. If I have forgotten anything I'll be happy to add if you could point it out to me. Thank you all again for any help that is provided. I LOVE my conversion wagon and hate to see it not road worthy. It runs GREAT when it does run!!

07-13-2011, 05:54 PM
Assuming there are no more exposed wires that could be causing another short; I'd say you have either a bad crank sensor or a bad ignition coil.

07-13-2011, 06:00 PM
Thank you Alloro! Could you tell me how I would go about having the mechanic check them in front of me? He said he checked those already but I have a feeling he didn't... and tomorrow when I go back there I want to have a list of things to check before I send my PCM back to rock auto and have them fix what he says is broken on it.
Any way to check the PCM itself first to see if there's anything wrong with it?
Thank you again for helping. I am a novice and have been scouring the internet and my manuals for days now.

07-13-2011, 08:22 PM
To be certian it isn't a power failure or ground problem at the PCM, make sure the MIL lights when it flat out dies. (This has been known to happen.)
Also what is the age of the battery and do all of the accessories die also, lights included or not? A bad battery can cause havoc as the charging system tries to charge what appears to be an open circuit which causes voltage spikes.
The PCM has two voltage regulators in it to provide 5 volts for the FI sensors (MAP, TPS, IAT, CLT, O2 and 8 volts for the cam and crank sensors which control the injectors and ignition respectively. If either of these fail the engine won't start/run.

07-13-2011, 09:18 PM
Thank you Alloro! Could you tell me how I would go about having the mechanic check them in front of me?

Any way to check the PCM itself first to see if there's anything wrong with it?

Some mechanics get quite irritated if you insist they work while you supervise them. They tend to want to get rid of you quick so they'll tell you just about anything just to send you down the road. Since he's the one saying it's the PCM, will he not charge for the the new one if it doesn't solve the problem? If he won't back up his diagnoses, then he's only guessing at the solution. There's no real way to test the PCM, the test equipment cost is beyond anyone that doesn't service them as a routine. The PCM is usually figured to be the problem only after everything else checks out as being good.

07-14-2011, 12:15 AM
@B-300-the battery in only a month old and the only thing that dies is the engine. What is the MIL? (may be silly but I gotta ask)

If it's the PCM then I have to send it back to Rock Auto and they will fix it (hopefully, we just bought it a month ago and I believe it's still under warrenty) and then my husband can do it himself-no need to pay someone I don't even know to do that :SPIN:

The only reason I wanted him to check them in front of me is because I don't know him and I don't want him to just take the easy road out (PCM) and it be something small. The last time something went wrong I was told it was the PCM, went out and bought a new one, then it turned out to be a short :ugh

However, from all my resources, including this website I am thinking that he IS right, and he's not tryin to jip me and will be sending the PCM back tomorrow to get it fixed.

07-14-2011, 09:28 AM
MIL=Maintenance Indicator Light also known as a CEL=Check Engine Light.

The short could've caused problems with the new PCM...just a thought there.

07-14-2011, 09:48 AM
Cardone says most ECM'/PCM's fail because something causes them to fail, like a sensor resistance out of whack, or a shorted solenoid, or any of the wiring leading to the sensors or solenoids grounding out.

I found one of the wires leading to my transmission had chafed on the tranny bellhousing and was shorting out. After I found that and fixed it, I had confidence in buying a new ECM, which has been trouble free for about 6 years now.

07-14-2011, 02:53 PM
I'm thinking maybe the crank sensor. sure sounds like those initial symptoms anyways. Maybe that could cause the ECM to fail?

07-14-2011, 09:13 PM
MIL=Maintenance Indicator Light also known as a CEL=Check Engine Light.

Also MIL can stand for: Malfunction Indicator Lamp/Light.

EDIT: I believe when the OP posted MIL in her first post she meant Mother-In-Law.

07-14-2011, 09:58 PM
EDIT: I believe when the OP posted MIL in her first post she meant Mother-In-Law.


although I refer to mine as :emouth:

07-15-2011, 01:07 AM
I believe when the OP posted MIL in her first post she meant Mother-In-Law.

:nono It was the OP that asked what a MIL was in post #6 because B-300 mentioned MIL in post #4. So Maintenance Indicator Light was the correct response.

07-15-2011, 01:08 AM

Why can't Johnny read? :teacher:

07-15-2011, 08:51 PM
Why can't Johnny read? :teacher:


Are you implying I was wrong to agree with the statement about the OP's first post being Mother-in-Law? :rolleyes: I know she asked about the MIL after it was mentioned, but that doesn't change what she meant in her first post and it gave me a chance to point out my MIL as :emouth:

All meant in good fun (just fyi) :D

Anyways, Aporia, be sure to keep us posted on your problem and I hope it all gets fixed so you can enjoy your van :rck:

07-16-2011, 11:04 AM
Are you implying I was wrong

With the utmost conviction! :D

07-18-2011, 09:56 PM
I'm not familiar with vans that old but I might be able to ballpark the diagnosis. The diagnostic flow chart for a crank/no start would start with checking for correct circuit voltages in the crank and/or cam sensors coming from and going to the PCM. This means checking for resitance, shorts, or opens in the power path, ground path, and the sensor(s) itself.

I don't know if your van is old or new enough for for the ASD relay. If equipped, the ASD relay shuts down power to the injectors and coil if the cam and/or crank sensor don't send a proper signal to the PCM. I'm not familiar with diagnostics for the ASD relay and circuits either but I'm sure it's another matter of checking for correct circuit continuity...powers, grounds, and loads....power and ground paths.

The next thing that would be checked is primary power and ground circuits for the PCM itself. Same drill with the other circuits I've mentioned. Power to and ground path from the PCM would need to be checked before condemning the PCM itself. I'm sure there are also going to be circuit checks for primary and secondary coil voltages as well as the fuel pump circuit. It could also include fuel pressure checks. Once all the applicable sensors and circuitry is shown to be good coming from and going to the PCM, then the PCM is deemed faulty.

I saw reference to Cardone products in the thread. I don't believe in Cardone products. I frequently recommend replacing Cardone products with known good products. I've used a lot of their remanufactured mechanical parts like calipers, rack and pinions, water pumps and all of them have failed immediately or soon enough that I could exaggerate and say it was immediately.

Yes, Hannah's first reference to MIL was indeed Mother In Law and that was funny. Arguments about who's right or wrong about subsequent posts should be put aside on that basis. Hannah, every time that light comes on, it's the Mother In Law from now on and she's mocking you. If you love your Mother in Law, then your MIL can be my Mother in Law.

Good luck with the repair.