Turbo Dodge Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
Howdy -

Troubleshooting an electrical issue on my 89 LeBaron convertible (2.5 turbo, auto, ca emissions) where the 12 button Navigator is being killed, assuming by stray voltage. Found a pin leading to the Navigator from the SMEC for fuel flow that has a constant 6V even when the car is off - seemed odd, so I bought a replacement SMEC (reman, BlueStreak from AZ) that indicates it meets my specs. When I install the computer the car runs terrible, then eventually will stall. Check engine shows code 27, fuel injector 2 issue. If I put the old SMEC back in, the car runs fine with no issues and no check engine light. (also notably the fuel flow pin from the SMEC has no voltage on it when the car is off, so I think I at least identified the problem killing my Navigator.)

I'm pretty sure I know the answer here, but wanted to put it out for any other ideas or feedback - my take is that the problem is the reman SMEC. Either it's not the unit I expect (ie, its for a different vehicle) or it just has a problem of its own. Seems unlikely for there to be an actual problem in the fuel injectors when the old computer runs without issue.

Any other ideas or thoughts? Thanks in advance!
 

·
Premium Member
Joined
·
395 Posts
Take off the covers of the SMEC and take a few pictures of both the power board and logic board. Do this for both SMECs. The number on the EPROM is a three digit code like 387, this is the last three part numbers of the SMEC and from this we can find out what car the SMEC belong to.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #4
Here are pics of the new remanufactured SMEC. EEPROM is 107. I won't have pics of the other one until later - but that one is the factory original. Car was built Feb 9, 1989. It's an 89 LeBaron convertible premium, 2.5L, turbo, auto, ca emissions. The part number on the original computer is 5235141. I matched that part number directly against this computer when replacing it (the AZ online details listed my original part number in the "this model replaces" segment explicitly.)

Let me know if this board is an incorrect board. I could also swap the power boards between them, if we think that's a problem too.

Thanks!
269519

269520
 

·
Registered
Joined
·
18 Posts
Discussion Starter #5
I did just look up that EPROM code - 107, according to the 89 parts book, is 5235107, which says it is a 2.5T, auto, CA emissions SMEC after 10-6-88. Would seem to be correct.

My factory part, 5235141 is not listed in the parts book explicitly. It has a later part number, would mine supersede the 107?

This at least would seem to rule out that I have the wrong part computer.
 

·
Administrator
Joined
·
24,577 Posts
Aftermarket ECM's are ALL JUNK, you need to find a used Chrysler SMEC either from a JY or open a thread in the "Parts Wanted" section.
You can also check here if you have the OE part #.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #7
Aftermarket ECM's are ALL JUNK, you need to find a used Chrysler SMEC either from a JY or open a thread in the "Parts Wanted" section.
You can also check here if you have the OE part #.
I don't think this is an aftermarket ECM - it's a remanufactured factory unit.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #8
Or, at least, one that has been tested. Though it does seem there is something wrong with it. I did talk to Marty (I buy stuff from him already) but in our convo we sort of agreed that getting a reman would probably be the best approach.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #9
Also, I happen to be a close to a repair place - United Radio - that one of my local parts stores says may do repairs on my existing unit. I may pursue that, too.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #10
OK - afternoon update. Below are the pics from my factory SMEC. EPROM is 141. Also, I did some more testing:
1. The reman unit definitely has a bad power board (thanks for the suggestion to swap and try) - if I put my original power board in the reman everything runs fine. If I put the reman power board in my original box I get the same injector problem. So, reman unit has an issue with the power board.
2. Turns out there is 5V voltage on the fuel flow line pretty much all the time from the SMEC. The reman and mine both behave the same. So this hunch that there was stray voltage on this line killing my Navigator units does not bear out.

Will be returning the reman unit since it's broken and just keeping my existing SMEC since it appears to not be broken.

I do have one last question - based on the pics for my SMEC, it is part 535141. I cannot find that part number in the 1989 parts catalog (or the 1990, which shows all SBECs anyways.) Is this because my part number superseded the original? Any insight into that would be appreciated.

Thanks -
 

·
Premium Member
Joined
·
395 Posts
I do have one last question - based on the pics for my SMEC, it is part 535141. I cannot find that part number in the 1989 parts catalog (or the 1990, which shows all SBECs anyways.) Is this because my part number superseded the original? Any insight into that would be appreciated.

Thanks -
The part number is 5235141 as we need 7 digits. This is from a 89 2.5 Turbo Auto Cali A body
 

·
Registered
Joined
·
18 Posts
Discussion Starter #13
The part number is 5235141 as we need 7 digits. This is from a 89 2.5 Turbo Auto Cali A body
Ohhhh. I never even thought to look through the other models. I see it under the A-body listing now. So, that means this SMEC, while a factory unit, was probably replaced at some point. (also, I typo-ed the part number in my last message.)

This is making me think that regardless I need to track down a good J-body computer.

New question - I think I know this answer - but the A body and J body computers are probably compatible, but tuned differently? If it is, does anyone know how so?
 

·
Premium Member
Joined
·
395 Posts
If you are bored and want some excitement check out
and open the files with MPTune

buy/install a flash module, and download any bin code to your SMEC. You are now the ruler of the world..
 

·
Registered
Joined
·
18 Posts
Discussion Starter #15
If you are bored and want some excitement check out
and open the files with MPTune

buy/install a flash module, and download any bin code to your SMEC. You are now the ruler of the world..
Well, this is really cool. I did load it up - pretty overwhelming. But - do you happen to know if there is a tuning difference between the A-body and J/G/P-body computers (all three use the same 5235107 part number, but the A body uses the 141)? Rather than me learning all of this just to figure that out, it seems easier to ask others who have been immersed in this deeply for a straightforward question.

Thanks!
 

·
Premium Member
Joined
·
395 Posts
I would suggest to ask Wowzer on the Turbo-mopar forum as he wrote the MPTune program. He usually answers quickly but is rarely on this forum.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #17
I will do that. Thanks so much for the info and the ideas - been very helpful!
 
1 - 18 of 18 Posts
Top