[Bibble]

I have a 91 Stealth SOHC 5spd that I've been having some troubles with. I bought it not running and found that the ecu was bad so I bought a rebuilt one to put in it. This allowed the car to start but it was missing pretty badly and, long story short, after some troubleshooting bought another ecu and it started running like it should.

It's been about a year since then and I just recently replaced the stock fuel line with some 6an summitracing ptfe lines and after assembling it I found that the fuel pump would constantly prime with the key in the on position (which it didn't do before and, afaik, shouldn't). Also, I changed the fuel line because of some unrelated issues (I'm trying to keep this car mostly stock). I figured it might be leaking but it has good fuel pressure and runs just fine without any leaks. After a bit of troubleshooting and testing relays I decided to swap in the rebuilt ecu to test and now it doesn't prime just like it's supposed to and starts fine, albeit with the aforementioned missing cylinders.

All the ecus have the number MD153354 E2T35372. Not sure if it matters but each one has a different number and letter beneath the e2t number.

tl:dr I have 3 ecu's with issues. I don't want to buy another one if I don't have to but it seems more expensive to rebuild than to just get another one. I have a soldering iron and could attempt to frankenstein them together but I don't have much experience doing that sort of thing. Also I wouldnt even know what I'm looking for lol. I could just live with the constant priming but it's particularly annoying since I know it's not supposed to. Any advice/info would be appreciated.

 

[white93gt]

All the ecus have the number MD153354 E2T35372. Not sure if it matters but each one has a different number and letter beneath the e2t number.

Well .... first thing I see wrong here is those ECU's are for a automatic transmission cars. The proper ECU for your SOHC 5 spd manual transmission car is MD153355 E2T35371. Can't say for sure that's the problem, but if it didn't matter they wouldn't have made 2 different ones.

 

[Bibble]

Well .... first thing I see wrong here is those ECU's are for a automatic transmission cars. The proper ECU for your SOHC 5 spd manual transmission car is MD153355 E2T35371. Can't say for sure that's the problem, but if it didn't matter they wouldn't have made 2 different ones.
View attachment 303208

I was under the impression that they were interchangable but that would make sense. Also I opened up all the ecus and found that the rebuilt one has an extra chip (the one labeled e910a). Not sure if it matters but that ecu looks perfectly fine inside to my untrained eye.

 

[white93gt]

I was under the impression that they were interchangable but that would make sense. Also I opened up all the ecus and found that the rebuilt one has an extra chip (the one labeled e910a). Not sure if it matters but that ecu looks perfectly fine inside to my untrained eye.

As you can see below the SOHC manual cars used same ECU for both Fed and Cali spec cars, but different ECU in automatic cars thru ’94. It wasn’t till ’95 and up they were all the same, meaning interchangeable. As I said I don’t know if that’s your problem or not, but I’d assume if they were meant to be interchangeable from ’91-’94 they would have been same part numbers in those years also.

I have no idea what the E910a chip is for, or what part number of that ECU is. Could be completely different ECU with top cover from correct part number ECU on it. Look numbers stamped on white plastic connector section of board assembly which should be last 4 numbers of E2Txxxxx number, with the ECUs you have now the 4 numbers there should be 5372 and correct ECU would have 5371. See example below for location of numbers I’m talking about, not one you need just an example of the location.

 

[Bibble]

As you can see below the SOHC manual cars used same ECU for both Fed and Cali spec cars, but different ECU in automatic cars thru ’94. It wasn’t till ’95 and up they were all the same, meaning interchangeable. As I said I don’t know if that’s your problem or not, but I’d assume if they were meant to be interchangeable from ’91-’94 they would have been same part numbers in those years also.
View attachment 303219
I have no idea what the E910a chip is for, or what part number of that ECU is. Could be completely different ECU with top cover from correct part number ECU on it. Look numbers stamped on white plastic connector section of board assembly which should be last 4 numbers of E2Txxxxx number, with the ECUs you have now the 4 numbers there should be 5372 and correct ECU would have 5371. See example below for location of numbers I’m talking about, not one you need just an example of the location.
View attachment 303220

Yeah, all of mine say 5372. I'll try ordering the correct one and see if that works. Thanks for the help, I'll post an update once I get it all back together.

 

[OhioSpyderman]

Getting into this a bit late...sorry.
I know little about the SOHC engines, but I assume (big ASSUME) that they still have an IAC?
Besides idle issues, they have been known to destroy ECU's (sometimes) when they fail.

Idle problems? ALL about IAC in one place!

Care and feeding of IAC. First, the acronym identifications. IAC- Idle Air Control TB- Throttle body BISS- Base Idle Speed Setting ECU- Engine Control Unit Over and over and over again I see posts about idle problems. Strangely enough most seem to think an adjustment screw is the source of...

www.3si.org

Just putting that out there for thought....

I agree with @white93gt (Don) that the right ECU for the right model year (and tranny) is always the best bet.

1991 1992 Mitsubishi 3000GT SOHC 3.0l CA Engine Computer MD153355 ECU E2T35371 | eBay

Will work in 1991 or 1992 Mitsubishi 3000GT or Dodge Stealth models with 3.0l SOHC non-turbo engines that have the MD153355 ECU code. Will work with either automatic or manual transmission. You MUST match your original part number.

www.ebay.com

I realize $170 is a lot of money, but everything associated with 20+ yr old cars are...

Bob.

 

[Bibble]

Getting into this a bit late...sorry.
I know little about the SOHC engines, but I assume (big ASSUME) that they still have an IAC?
Besides idle issues, they have been known to destroy ECU's (sometimes) when they fail.

Idle problems? ALL about IAC in one place!

Care and feeding of IAC. First, the acronym identifications. IAC- Idle Air Control TB- Throttle body BISS- Base Idle Speed Setting ECU- Engine Control Unit Over and over and over again I see posts about idle problems. Strangely enough most seem to think an adjustment screw is the source of...

www.3si.org

Just putting that out there for thought....

I agree with @white93gt (Don) that the right ECU for the right model year (and tranny) is always the best bet.

1991 1992 Mitsubishi 3000GT SOHC 3.0l CA Engine Computer MD153355 ECU E2T35371 | eBay

Will work in 1991 or 1992 Mitsubishi 3000GT or Dodge Stealth models with 3.0l SOHC non-turbo engines that have the MD153355 ECU code. Will work with either automatic or manual transmission. You MUST match your original part number.

www.ebay.com

I realize $170 is a lot of money, but everything associated with 20+ yr old cars are...

Bob.

I've replaced the IAC in that car already, so I don't think that should be an issue. Thanks for the info though.

 

[BlackStealth]

I was under the impression that they were interchangable but that would make sense. Also I opened up all the ecus and found that the rebuilt one has an extra chip (the one labeled e910a). Not sure if it matters but that ecu looks perfectly fine inside to my untrained eye. View attachment 303209

That extra chip is an EPROM or PROM. That's a rare find. It makes modifying fuel / timing tables much easier.

 

[white93gt]

That extra chip is an EPROM or PROM. That's a rare find. It makes modifying fuel / timing tables much easier.

Good info I find interesting. Does that indicate it might be a later remanufactured unit since it’s for a ’91 ECU, that normally might not have had that chip?

 

[BlackStealth]

More like an earlier version. To save money they would have removed the eprom.

 

[Bibble]

Car runs just fine now with the new ecu in, no issues so far. Thanks for the help guys.