Reman Renix ECMs

[DirtyComanche]

Has anyone bought any of the remanufactured ECMs for the Renix?

 

IE:

https://www.rockauto.com/en/moreinfo.php?pk=26928&cc=1179996&pt=2896&jsn=11503

https://www.rockauto.com/en/moreinfo.php?pk=322131&cc=1179996&pt=2896

 

I got my ECM rather wet, and wound up pulling it apart to try to get it dry.  The capacitors look pretty swollen, but not leaking, and there's some existing corrosion on the board along with some failure of the lacquer or conformal coating they put on it.  I'm not sure if the ECM will function after I dry it out either, but it might, it was still somewhat working before I realized it was full of water.

 

Either way, I'd like to find another spare.  Anyone bought one and had success with it?  Has anyone changed the caps in their own?  Curious if it might improve how things run.

[JMO413]

I bought the Cardone one from AutoZone and have had no issues

[Minuit]

Pics of yours? Recapping it should be a straightforward procedure. Conformal coating can always be reapplied.

[DirtyComanche]

2 hours ago, Minuit said:

Pics of yours? Recapping it should be a straightforward procedure. Conformal coating can always be reapplied.

I'll grab a couple later.  It's your typical 80s PCB though, so lots of meat to solder too.

[cruiser54]

There's gotta be spares floating around. I have a few early ones. 

[DirtyComanche]

Like I said, it's pretty typical 80s PCB.  Big traces.

 

 

You can see corrosion on the back side.

 

I thought the caps were swollen but it might be the conformal coating.

 

I think it's been wet before based on the amount of corrosion in the case.

 

Anyway, I ordered that Cardone one to cover my butt.  No luck on the yards here having one.  I don't know if the one I swapped in is screwed, or if something else went wrong.  I guess I could clean this ECM and put it back in too.  It bucks bad sometimes when hot, part or full throttle.  TPS is adjusted right, and seems to be fine through the full sweep.  I'm going to throw new plugs in it and see if I have a cap and rotor (I should), wires are new.  If I have a spare cap I'll check the indexing of it, didn't do it before because everything ran fine and I didn't have an old cap to cut up.  If that doesn't help I'll throw a new O2 sensor in it and then try reseating the CPS or swap it out.  CTS and IAT are both reading correctly.

[Minuit]

That's about what I expected to see. Some Jeep electronics of this era are very prone to developing cold solder joints, and any exposure to the elements would make that tendency worse. I don't know about the ECUs but the radios certainly do it very badly. That's a plated-thru-hole board, which makes things better, but you'll still want to check for cracks in the solder. Especially check around the larger parts and any area that is under mechanical stress, such as the big connector.

 

Those caps don't look out of the ordinary to me, but I could be missing something based on the camera angle. You're a smart guy, I'm sure you know when something looks wrong. The tops of the caps should be a perfectly flat surface. There are not many electrolytic caps on that board at all and you could replace them for a couple bucks (for extremely high quality parts) if desired.

[DirtyComanche]

I think it is just the conformal coating that was giving the illusion that they're bulged.

 

I think I'll clean the corrosion off it and seal it back up (I think I've got some stuff at work for that) and see if it still chooches.  I'm tempted to actually put a drain hole in the case at the same time, the connector is in absolutely no way waterproof (or even water resistant), so if moisture can get in it's better to give it an easy way out.  Maybe.

 

I got the "new" (random junkyard spare I had) ECM to play nicely by reindexing the distributor...  And figuring out that the fuel pump is on its way out.

[DirtyComanche]

Here's a Cardone "remanufactured" one taken apart.

 

 

Pretty disappointed with the complete lack of fawks that was subject to.  They did change the caps though.  I'll take it to work and clean the corrosion off and touch up the coating I guess.

[AZJeff]

12 hours ago, DirtyComanche said:

Here's a Cardone "remanufactured" one taken apart.

 

 

Pretty disappointed with the complete lack of fawks that was subject to.  They did change the caps though.  I'll take it to work and clean the corrosion off and touch up the coating I guess.

What the heck are those tracks of brown crud on the solder side of the board?   They almost look like carbon tracks from arcing, but the photos are not real detailed.   That's kinda disappointing on a "reman'd" assembly.

 

 

 

[DirtyComanche]

3 hours ago, AZJeff said:

What the heck are those tracks of brown crud on the solder side of the board?   They almost look like carbon tracks from arcing, but the photos are not real detailed.   That's kinda disappointing on a "reman'd" assembly.

 

 

 

The photos are detailed but the forum dithers them pretty hard.  I could upload to imgur but eh.  I think they dropped the soldering iron, twice.  It's like it's burned, but definitely not arc burns.  Or it might just be some sort of dirt/crud.  I'll try cleaning it when I get to work, then I'll put some lacquer over it.  I suspect the trace they bodged was what caused it to fail.

 

Still waiting for a fuel pump, then I'll see which of the three I have works best.

[Minuit]

That is about what I would expect from Cardone. Just curious - what kind of caps did they use?

[DirtyComanche]

29 minutes ago, Minuit said:

That is about what I would expect from Cardone. Just curious - what kind of caps did they use?

Nippon-Chemicon KMC I believe.

 

I think the black scuzzy stuff was nasty old flux, or something, that they then soaked with whatever they used for conformal coating.  I managed to clean it off reasonably with heptane and put lacquer over the areas I cleaned.  There was a bunch of fuzz from the Q-Tips that got stuck in it, but eh, that's not a big deal.

 

 

Man does the forum ever dither that.

[DirtyComanche]

Next question...  any idea if you can tell what version of firmware is on these things based on the markings?

 

This chip has a sticker:

 

 

 

B0107E.

 

On the on the one that got wet it's B1143F.  Serial number?

 

I'd assume whatever version of firmware was flashed to the ROM would have had a sticker or other marker to go with it.  It would seem unlikely they would only mark the housing via the part number of the whole assembly.

 

I'm not sure if this ECM is actually an 89/90 like they claimed.

[DirtyComanche]

I wound up putting that Cardone one in.

 

It actually does run better with it versus the 32~ year old one I got out of the junkyard.  Idle is smoother, and doesn't idle as low, and just smoother on and off the throttle in general.

 

I'm not going to bother to try the one that was underwater again.  But I suspect it is fine too.  It's a real PITA to swap them because I have a bunch of extra wiring that's in the way, otherwise I would try it.