need help gettin truck running again

Hey, so I'm posting for my boss (he is a car guy) because he is too stubborn and if he doesnt get a vehicle soon, I'll lose my job. I'll try to give as many details as possible but I'm not really a car person.

Anyways. he has a 2001 Dodge ram 1500 st 5.9 v8.
The truck ran alright except for it had a tick in the engine..and no one could figure out what it was. Apparently the last week before it died it wasnt running as good. It dies, and he has the (original) rebuilt engine that is waiting to go in (he hadnt had time previously but this forced his hand. So over the weekend he swapped it out. started it up for the first time and it was struggling but it was going, didnt want to idle well. He shut it off after about a min. Let it cool off and checked everything, everything looked good. Started it back up was idleing fine but then was developing a misfire, ran for 5 mins before it backfired and he cut it off. Apparently it was throwing P1391 code. Checked everything, and decided to replace the crank sensor. Replaced it, and it is still throwing the same code. It's rough to start, has to pump the gas, but it will start, and run for 5 mins, then backfire. Same thing everytime now. He thinks it might be the ECM now. I think it might be a bad crank sensor even though it is new. Any help, ideas, anything I can pass along to him to try? Trying to save my job here, and save him money if I can. Is there anyway to check to see if the ECM is bad without going to a dealer? Our dealer said it would be 2 weeks before they can see it. Any help is appreciated, thanks!

Edit: While trying to get it to work he has also replaced other things (sensors, etc). He basically thinks it can only be fuel or electrical related.

Now i'm curious what your job is.

It could be plenty more than fuel or electrical. Its throwing a code for a reason, if the PCM was bad, it would have a lot more problems than it does.

The rough idle and shutdown could be caused by crank position issues. It uses that sensor to determine engine rpm, from that, everything else related to engine operation. If that sensor is either bad or not picking up a signal every now and then, it will run crappy or not at all.

Since the new engine was put in, that means the tranny was pulled off along with the torque converter. The crank position sensor reads notches in the flywheel, if something is in one of those notches or the spacing is off or the sensor was a cheapie. Then a problem could arise. Cheap sensors are no good, you cant count on them. You can test it however.

Part 1 -How to Test the Crank Sensor (1997-2001 3.9L, 5.2L, 5.9L Chrysler)

Before he goes jumping into the fuel system, or starts throwing parts at the electrical system, he needs to diagnose the problem. Start with the crank position sensor. Its throwing one code. Bad PCMs will usually throw multiple codes or just fail to communicate.

My job is an appraiser..well I'm training to be one..so having a vehicle is crucial to go on inspections (right now he is having to rent one which is costing even more). He unfortunately had 3 vehicles go bad in under a week. His corvette, a mini cooper, and his truck.

I'll relay the info and see what he thinks. thanks

Damn, he's got even worse luck than my sister in regards to vehicles.

I just looked up that particular code and it seems that it can be tripped by either the crank or cam position sensor.

You say that he bought a new one. Any idea what brand? I've learned from experience, NEVER EVER buy "no name" stuff that you find on eBay. Just don't. Period. It's either going to be the wrong part for the application or it won't last half a year before needing to be replaced again.

The camshaft position sensor I believe is located in the distributor in these engines. I really don't know what to say because I've had the fortune of never having to screw with anything involving the distributor on mine. I don't even know what the part looks like. What I do know is that the fuel injector timing is dependent on the distributor and you really don't want to pull it out of the engine unless you are fully prepared to re-time stuff with speciality tools. If the "fuel syncing" is off, the engine will never run right, period. I bring this up because you say that the engine that he has in right now was rebuilt. Depending on the "level" of rebuild, pulling the distributor is somewhere between "maybe" and "most definitely."

Try this for much more detailed information...

http://bionicdodge.com/Download/Camshaft Timing and Setting Fuel Sync.pdf

A bit off-topic, but what's wrong with his other vehicles? If it's something simple with either one, you might be better off sorting that out first, ESPECIALLY if your job relies on it, LOL. C'mon, he's got a truck, a sport compact and a sports car. He's definitely got SOME money to spend.

Yeret makes a point. If whoever did the rebuild was lazy or didn't know how to set fuel sync, that would be another place to look at.

Yeret said:

You say that he bought a new one. Any idea what brand?

Depending on the "level" of rebuild, pulling the distributor is somewhere between "maybe" and "most definitely."

A bit off-topic, but what's wrong with his other vehicles? If it's something simple with either one, you might be better off sorting that out first, ESPECIALLY if your job relies on it, LOL. C'mon, he's got a truck, a sport compact and a sports car. He's definitely got SOME money to spend.

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1. bought it from advance auto

2. He seems to think it was well done, but there has definitely been questionable work from them in the past

3. he gets most of his cars actually really cheap. both the vette and mini for probably 5k total.. mini wasnt running and interior of the vette was trashed.

vette's problem(s) - the coolant isnt making it back to the coolant tank, it is staying in the overflow, latest problem he was driving it and there was white smoke

mini has had numerous problems most of which has all been fixed except for it is drinking coolant..not sure where it goes..thought maybe it is making it into the oil, but not sure how..possibly through the heat exchanger or whatever, so he is going to take that apart and possibly replace...and now it's new problem is oil pressure



as far as anything with the truck.. he seems pretty certain it's the ecm so he is sending it to someone company that tests them..think he already did that this morning..idk.. I'm still trying to get him to even check to see if the crank sensor is working properly..very stubborn.. but thanks for all the help..I'll update when I find out more, or if he decides to start listening to advice