2nd ECU blown in 2 months?

[MichaelSuch]

Alright guys, I got this '90 GSX. I bought this car awhile back and I had it running fine, till one day it wouldn't start. Opened up the ECU to find a few burn marks and such. Popped in another one from a '90 and was running great again, for another month (I probably put on only 400 miles since it has so many damn problems) and now when I wanted to go take it to get it aligned, wouldn't start. Stock boost gauge doesn't move to 0 like it should, I pulled the ECU yet again to find out this one is blown too! When I got it I opened it up and everything was fine.

Why do I keep blowing ECU's? Every time when I unplug something I always disconnect my battery first, so that's not the problem. I'm getting sick of it and am about to get out of this game.

 

[snowborder714]

Do you know what part in the ECU is being blown? This will obviously help you determine the main cause of you blowing ECU's.

Post up some pictures if you can.

 

[toofast82]

It's possible the second one was going bad and it coincidentally went out shortly after you installed it.
It could be an electrical short destroying the ecu internals?
Time to send one to "steve" to check it out!

 

[MichaelSuch]

My pictures suck because I have an expensive camera and am too much of a newb to learn how to use it. But I highlighted the areas.

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Click them to make them bigger. Those are two separate ECUs.

 

[snowborder714]

You should learn how to use macro mode. That is what you need to take close up pictures. It usually is a picture of a little flower. Once you get some better pictures that you can see detail on, it'll be easier for us (or steve or twdorris) to help diagnose what's wrong. The more pictures/angles you take the better (and they all don't have to be really close on the little area you circled).

 

[MichaelSuch]

I was trying macro mode, help the button down but it wouldn't take any pictures. I think I need a smaller lens for pictures that close, mine is 14-45mm...

 

[awdcsm]

also if u use high ohm injectors will also kill an ecu, do u have aftermarket injectors?

 

[Jdog]

the ISC driver can also get blown from a bad ISC if I remember correctly.

 

[steve]

also if u use high ohm injectors will also kill an ecu, do u have aftermarket injectors?

the ISC driver can also get blown from a bad ISC if I remember correctly.

Neither of these have anything to do with his problem.

I pulled the ECU yet again to find out this one is blown too! When I got it I opened it up and everything was fine.

Why do I keep blowing ECU's?

Both of those ECUs have original capacitors and they have now leaked on you. When you opened then up you should have noticed them and had them replaced. From what I can see in those pictures (which isn't that much) it's you using bad ECUs that keeps causing them to fail not the car.

 

[MichaelSuch]

Would these ECU's be worth repairing or am I better off buying another used ECU and having it worked on?

 

[snowborder714]

If all it needs is cleaning and new caps, I'd repair it. Actually, I have yet to find a problem with an ECU that's been in my possession that hasn't be worth repairing.

 

[steve]

Would these ECU's be worth repairing or am I better off buying another used ECU and having it worked on?

Hard to say since the images are so out of focus.
I also don't know what your source for these is charging you. If you were to find another in perfect shape having the caps replaced before they damage the ECU is cheap.

 

[MichaelSuch]

I paid $75 for the last one, called a few junkyards in the area, none of them have any DSMs. I glanced at the classifieds and nothing came up, I'd probably be paying $75+ again anyways and then however much it is to replace the caps. I'd like to get the car on the road ASAP so my better option I think would to have it repaired instead of searching for another ECU for a few days, waiting for another week to ship and then however long it takes to ship it out to have the caps replaced... Steve are you busy?

 

[steve]

Send them on up. Address is on my homepage.

 

[MichaelSuch]

Alright, I'll have them out tomorrow...

 

[steve]

Did a good ECU fix you up?

 

[MichaelSuch]

Yup sure did, still got more brake work to do though before I can start DD'ing it again. Thanks Steve!

 

[TrevorS]

Neither of these have anything to do with his problem.



Both of those ECUs have original capacitors and they have now leaked on you. When you opened then up you should have noticed them and had them replaced. From what I can see in those pictures (which isn't that much) it's you using bad ECUs that keeps causing them to fail not the car.

Is there a typical life for the ECU supply capacitors? My OE ECU burned up a year and a half ago, but it was never clear why (the board itself was burned)! I replaced it with a professional rebuilt.

 

[N2aquatix]

I do actually have some experience on this subject. If you buy a used ECU instead of a professional reman it will burn up (from my experience). I have had 3 different ECU's in my 1990 laser RS. The ISC is completely disconnected and my idle stays at 1000rpm all the time no matter what. There seems to be a finite life-span for the ECU even if you replace the caps. From what I understand, the professional reman units will last about 5 or 6 years if you're lucky before the secondary processing systems start to go bad. That is why most DSMers eventually switch to AEM EMS because it is a state of the art system that can handle the engine management for this car and not burn-out plus you can tune it to whatever set-up you might have under the hood.

Cheers

 

[jrohner]

I do actually have some experience on this subject. If you buy a used ECU instead of a professional reman it will burn up (from my experience). I have had 3 different ECU's in my 1990 laser RS. The ISC is completely disconnected and my idle stays at 1000rpm all the time no matter what. There seems to be a finite life-span for the ECU even if you replace the caps. From what I understand, the professional reman units will last about 5 or 6 years if you're lucky before the secondary processing systems start to go bad. That is why most DSMers eventually switch to AEM EMS because it is a state of the art system that can handle the engine management for this car and not burn-out plus you can tune it to whatever set-up you might have under the hood.

Cheers

Most DSMers switch to AEM EMS? I doubt it. Plus, you don't need AEM to tune, you can tune an OEM EPROM ECU basically however you want and it works great. Yes at some point you'll probably want something better, but even for 500+awhp these ECU's work great. The Evo 8 ECU has ran cars with over 700awhp, sure they have more processing power and memory than these do but they're still an OEM ECU that started out running a 250awhp car.

I've never had any ECU trouble yet in any of my DSM's and I own & have owned quite a few. Mostly 91-92 1G's. Their ECU's have been in use for a lot more than 5-6 years, without any trouble. On my 92, the only reason I swapped ECU's was for an EPROM from a 91 so I could tune it.

I have, however, worked on a couple non-turbo 1g's for people that have had bad capacitors, and one did burn a big hole through the board. I currently have a couple turbo 1g EPROM ECU's that look to need capacitors but don't have any board damage.

 

[TrevorS]

I've never had any ECU trouble yet in any of my DSM's and I own & have owned quite a few. Mostly 91-92 1G's. Their ECU's have been in use for a lot more than 5-6 years, without any trouble. On my 92, the only reason I swapped ECU's was for an EPROM from a 91 so I could tune it.

I have, however, worked on a couple non-turbo 1g's for people that have had bad capacitors, and one did burn a big hole through the board. I currently have a couple turbo 1g EPROM ECU's that look to need capacitors but don't have any board damage.

Sounds good! Mine was 18 years old and still working fine when it burned (boy, did it stink up the car). So, I'm hopeful this rebuild will be good for the remaining life of the car (currently 125K).

 

[steve]

I do actually have some experience on this subject. If you buy a used ECU instead of a professional reman it will burn up (from my experience).

There seems to be a finite life-span for the ECU even if you replace the caps. From what I understand, the professional reman units will last about 5 or 6 years if you're lucky before the secondary processing systems start to go bad.

I have a bit more experience than most on this topic.

All electrolytic capacitors have a limited life span but the 47uf and 100uf capacitors used in our ECUs and TCUs had a design defect that caused the seal on the wire leads to leak.
Once they leak removing the electrolyte from the circuit board is more work than most commercial rebuilders are willing to spend on their reman process. Many don't bother to clean anything and just toss a couple of capacitors in it and if it works it's done.
Others will do some minor repair list replacing the SMD caps that have been eaten off the board with thru hole parts but little attention to cleaning so the electrolyte continues to eat away at the circuit board until it eats something critical and it stopc working or shorts out and starts burning.

If the ECU still has original capacitors your playing russian roulette with time. It's not if but when the caps will damage and kill the ECU.

If the repair work is done correctly there is little reason why the ECU won't last another 20 years, I doubt most of the cars will last that long.