Between this forum, my truck, and the ram forum there seems to be an epidemic of “crank, no start”. After exhausting all the other possibilities I’ve come to the conclusion that the ECM is bad.
Used and aftermarket replacements appear to be nonexistent. The few places that claim to be able to repair them have such dubious online reputations as to be not considered as a viable option.
It seems to me that it should be easy enough to fit an updated OBDII replacement.
I can’t find any mention of anyone trying it in the forums. There are a lot of aftermarket ECM manufacturers out there. Anyone try any of those products?
I’ll be damned if I’ll scrap a perfectly good truck for an errant transistor on some printed circuit board.

 

I recently replaced mine via Rock Auto. I'm happy with it. This is the first gen forum. OBDII is 96+

 

I often thought Rock Auto would be a good source for an OBD. My impression in dealing with Rock Auto to the tune of several thousand dollars in a wide variety of automotive parts is they wont tolerate lousy parts suppliers. Doesn’t mean they wont sell lower end, less expensive parts for those on tight budgets but that’s not the same as shady suppliers. I have an OBD1 and that’s a different world than OBD2 but if I needed a 2 I would give Rock Auto serious consideration.

Curious, did you have options at Rock Auto and what did you go with?

 

My truck is a ‘92. Sorry, that wasn’t clear. I checked Rock Auto and the ECM they used to carry is no longer available.
What I’m asking is has anybody tried replacing the original OBD1 ECM with a newer one that is an OBDII?
Are the newer models still a speed density system with a MAP sensor, or were the newer ones a mass air flow system, with a MAF sensor?
Anybody try an aftermarket ECM that would be a replacement for a newer truck?

 

I cannot imagine that working.

 

OK I'm thinking based on what I saw for the Dakota on eBay for the 3.9 that you can look at 91 thru 95. Then I realised they use the same puter in other models with the same motor. So I looked and the 94 Ram1500 5.2 computer on rock auto is available. You will have to research whether or not it is compatible with yours. They also put the 5.2 in vans and IDK what else. 95 had a change in the trans but IDK if that involved more than the physical redesign of internal ports.
Edit- I forgot to mention that you should buy on a site with known customer service reliability and or use PayPal to protect yourself from a bad seller.

 

Thanks. That’s helpful. The only change the made with the automatic trans is changing from hydraulic actuated shift to electric actuated shift. 46RH to 46RE.
I’ll do some hunting and find out if the ECMs are compatible. The things that might make a difference would be GVW, towing capacity, rear end gear ratios, and maybe tire size.

 

I have a ‘93 and I always find a couple PCMs for my truck on there (Ebay). In fact I looked a week ago just for fun and there were three used ones in there. I bought a “refurbished” one from a joint in Florida. That was 3-1/2 years ago. The voltage regulator didn’t work in it (I bypassed it with an external regulator) but everything else has worked perfectly fine.

 

I'm fairly certain the computer has no effect on any of those things.

 

Believe it or not you can also check for a Jeep ecm of the same year and engine size. Jeep was the 'test bed' for the Magnum series of engines ...even to the point of developing the HP ecm that's now obsolete. GM & FoMoCo guys could 'chip' their ecm's for better performance, us Mopar believers had to buy the ecm as none of the aftermarket chips would work.