I think all my problems are solved so I'm posting for others. I'll try to include terms people may search.

First, the solutions - replaced the pcm / ecm and no more dying. Got rid of the steering pull by adjusting the caster using the top of the Aframes.

My 99 dodge was dying while going down the road. At first it only died when it was hot outside and later the outside temperature didn't matter. When the truck would die my odometer would display no bus and I would have no fuel pressure. After sitting from 1 to 45 minutes the truck would start back up (fuel pressure would come back up to 49psi), sometimes it would die a mile down the road and sometimes it would get me home without dying. I replaced the crankshaft position sensor, camshaft position sensor (distributor pickup plate), ignition coil and finally the computer ( pcm / ecm ) solved the problem. Dodge wanted $600 - I bought a used /rebuilt one from Auto ECM in Grand Prairie, Texas for $295 (lifetime warranty).

The truck was also pulling to the right (pulls to the right) - I could exit the freeway by turning loose of the wheel. I had the alignment checked out and they said it was in tolerance and wanted $700 to go through the entire front end and brakes. I rotated tires, replaced the right caliper, brake line, brake shoes and front bearings - still pulled right. On my 99 you can adjust the position of the top Aframe by moving the front and rear top positions inward or outward thus moving the caster negative (to the front) or positive (to the rear). More negative caster on one side will cause pull to that side. With my impact wrench and a 24mm socket it was easy to trial and error the caster on both sides until I had no pull. I may be offsetting another problem but it drives great and the tires don't appear to be wearing.

Previous posts by me when I had the problems:
https://dodgeforum.com/forum/2nd-gen-ram-tech/177151-99-dodge-ram-1500-computer-replacement.html

https://dodgeforum.com/forum/2nd-gen-ram-tech/172783-99-dodge-ram-1500-2wd-pulling-right.html

The classic "dies when going down the road" thread by people with 99 Durangos:
http://www.carsurvey.org/viewmorecom...w_41149_1.html

Best of luck.

 

June 2010, my dying problem is back. Auto ECM and Grand Prairie replaced my ECM - still dies. I bought another lifetime warranty ECM from ebay - still dies. Either I got two bad replacement ECM's or now another problem is causing the same problem that I believe was being caused by the ECM. Ideas?

 

sounds like the fuel pump just stops workin kinda? and for some reason will come back later. thats wicked though, maybe check out the pump if u got spare time. im at a lose.

 

check for spark and fuel pressure.
sounds like your ASD (auto shut down) might be tripping, which will shut down both.

 

I've only been driving the truck short distances since it started dying again. It seems to be getting worse and dying at cooler outside temperatures (once recently at 58deg F). I bought an obd2 diagnostic tool from scantool.net and started logging all available data while I drove hoping to capture an error code or tell what is failing. I'll be happy to email an excel file of the data from a trip when it died to anyone who wants to take a look. Frank

 

I would be interested in looking at the data, but, not sure if I will be able to make heads or tails of it....... I will send you my email address via PM.

 

Sounds like you're losing your ground or connection to the pcm. All to common of a problem with the 5.2 & 5.9 Jeeps.

See if you can replicate the problem by tapping on the pcm or by wiggling the pcm connectors. Also get some good contact cleaner and go to town on all your pcm connections. Gotta be spotless, then hit 'em with some dielectric and see if that helps.

^

 

I would be love to have a chance to look at what is going on inside your trucks head. I will pm you my email address.

I had a no bus problem in the past, but a new pcm fixed this, some how mine failed internally, and gave me a checksum error code (forgot the po#)

Your pcm may not log the checksum error code because it resets itself after a serious error. The only way I found out about mine was with a drb scan tool at my local chrysler stealership (got a buddy there).

First: check the asd--this is far easier to understand and investigate (and suits your problem), if it isn't that, read on:

some explaination: read this if you want to understand what is going on inside the pcm:

Without going too far into software engineering, the definition of checksum (as I understand it) is: The pcm is constantly monitoring info from all the sensors on the vehicle. Voltage input from the sensors ultimately ends up as a hexidecimal code (programming language) which uses numbers and letters to tell the computer what is going on. Hexidecimal has a set amount for what it can define, up to 256 different values.

The checksum is used to judge the values and determine what needs to be done (adjusting A/F ratio, spark timing, things like that) or if a CEL is to be set.

A checksum error means that one of the sensors logged an unknown (or, not understood) value.

A good way for me to put this is: hexidecimal ends at 256, thats it, no more. If i can only count to 256, and you give me a math problem that equals 257, I cant understand WTF is going on... then my head explodes (i.e. the truck dies).

Now that you're all asleep, here are the solutions:

This is possibly the cause of the problem: one of your sensors is logging info that doesnt make sense to the pcm. The root of this is probably not a bad sensor (there is a hex value that determines if a sensor is faulty), rather, it is one that has a short in the wiring between it and the pcm. You hit a bump, wires short, sends pcm wierd info, pcm goes WTF IS THIS!?!?! and it kills the truck.

How you can test it: (it would be good to have a buddy follow you) Start the truck, drive as carefully as you can avoiding all potholes to a secluded spot where it would be alright to have your truck die. Get ready, then hit the **** out of a pothole, curb, etc. It may be necessary to vary your speed and angle of approach to duplicate the problem, if your truck dies shortly after, you have some wiring to check.

Best Of Luck

 

Mad Scientist,
How do you check the asd, just switch it out with a similar relay?

Also, to save you from reading all of my posts. When this truck first started dying, it would display "no bus" in the odometer window, all gauges would go dead, and most of the dash lights - air bag etc would be on. Now when it dies (1 plus year after replacing the pcm) the gages don't go dead and no light are on and no "no bus" message.

Thanks

 

Switching the asd out should work, theres a procedure for checking it (found it when i was having no bus issues) but i cant for the life of me remember now. Might take a gander at the service manual (available here) and see if its in there.

Didnt take that last part into account, thought you meant you were having the same issue, lol. If its not saying no bus, its likely not pcm related. Oh well, maybe that write up will help someone in the future.

Check the asd, and I would look hard at the fuel pump/distributor as well.