removing ECM

[juntjoo]

is it supposed to come right through here as the Haynes manual says? its not budging. do I need to disconnect the wire harnesses first? I'm starting to get that feeling I always do before I break something and I don't want to break anything here. help please. thanks

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[bryanwheat]

It will slide out than you can unhook the harness.

 

[Bud92gsx]

Did you get all the bolts out? I grab the bottom, and slide the bottom out first. You don't need to but I remove that peice of carpet right there to the right..

Yes it should slide right out..Then unhook the harness and there you go.The harness doesn't go that far, so don't try pulling it 8 feet from where it's supposed to be.

 

[juntjoo]

thank you. removing that piece of carpet was key

 

[juntjoo]

so it looks pretty good right? I don't see any signs of damage. I just figured out through here that it doesn't have the Eprom chip so apparently I can't hook up some popular diagnostic tools or something so I was wondering if you guys could tell me what my options are here for diagnosing the ECU. in particular I'm trying to figure out if my ISC isn't operating correctly(not cycling in and out) because of a problem on the end of the ECU. I'm still waiting for an ISC to arrive in the mail, but the one that came with my car and one used one(that I just returned because it didn't pass a resistance check on pins 4&5) both only wiggled when I tested them and I read somewhere someone with the exact set of symptoms resolved the problem with a new ECU, so... is there a way to test these?

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[bryanwheat]

You can most certainly do diagnostic testing on a non eprom.

 

[juntjoo]

cool. I'll look into that. anyone have experience with these with any recommendations please chime in.

 

[bryanwheat]

Well you said that the isc that you had tested bad so that would be the reason why the car wasn't idling good.

 

[WES_393]

Take the case off the ECU and take a look at the circuit board. Make sure there isn't any signs of corrosion from leaking capacitors. Here's a link for good examples of corrosion.

ecurepairhome [ECMTuning - wiki]

 

[juntjoo]

Well you said that the isc that you had tested bad so that would be the reason why the car wasn't idling good.

not necessarily though.

 

[bryanwheat]

IF the isc is bad than it isn't going to work correctly.

 

[juntjoo]

I read that the ISC can behave wrong if there is a problem on the ECU end, which is why i'm checking it out while I wait for another ISC to arrive

 

[DSM1G90]

Did you disconnect the negative (not positive) cable from the battery before pulling the ECU?

See those four little black thin strip chips to the upper right on the momboard? Those are the sensor drivers for the IAC and the other required sensors they can easily be blown since it doesn't take much to knock them out - like disconnecting sensor connectors with the battery still connected and get accidently shorted which will blow these drivers to kingdom come.

Only takes less than 2 amps to knock out one of these sensor driver chips.

You might have to get another ECU.

 

[rlacasse1]

I read that the ISC can behave wrong if there is a problem on the ECU end, which is why i'm checking it out while I wait for another ISC to arrive

But if you had the ISC disconnected from the harness when you tested. And it tested bad. Then it is the ISC. There's no way around that.

 

[And_44]

Could have the caps replaced. They appear to be the factory originals. I've replaced mine in past cars with minor running issues and some times it fixes them. You may not see any leakage but it can be slight and only under the caps at the moment.

 

[juntjoo]

But if you had the ISC disconnected from the harness when you tested. And it tested bad. Then it is the ISC. There's no way around that.

not trying to get around it. its also possible to have problems other than the ISC. indeed if when I pop in this ISC i'm waiting for and it works fine I won't worry more about it, but for now i'm checking out other possibilities and as I noted earlier I've read example(s) of the ECU causing idling problems.

 

[92AWDHX40]

I had a bad isc ending up damaging my ecu, had to fix the ecu.

 

[juntjoo]

Could have the caps replaced. They appear to be the factory originals. I've replaced mine in past cars with minor running issues and some times it fixes them. You may not see any leakage but it can be slight and only under the caps at the moment.

who knows. if anyone knows how to test these let me know. I'll be looking into that as soon as I can. right now gotta fix stupid multiple rusted bolts, in particular one getting in the way of fixing rear brakes, so gotta get that done...

 

[juntjoo]

Did you disconnect the negative (not positive) cable from the battery before pulling the ECU?

See those four little black thin strip chips to the upper right on the momboard? Those are the sensor drivers for the IAC and the other required sensors they can easily be blown since it doesn't take much to knock them out - like disconnecting sensor connectors with the battery still connected and get accidently shorted which will blow these drivers to kingdom come.

Only takes less than 2 amps to knock out one of these sensor driver chips.

You might have to get another ECU.

nope, did disconnect (-)battery cable

 

[rlacasse1]

not trying to get around it. its also possible to have problems other than the ISC. indeed if when I pop in this ISC i'm waiting for and it works fine I won't worry more about it, but for now i'm checking out other possibilities and as I noted earlier I've read example(s) of the ECU causing idling problems.

Sure it's possible. I was just pointing out that if you tested a ISC and it was bad, then it should probably be fixed before you move on to other things. I guess you're just testing other things in the meantime while you wait on a new one to arrive though?

 

[And_44]

No way to test leaky caps. If they are old/leaky they may not be able to handle the electrical current running through the board very smoothly so thats where you'de get the irractic idle and running. Also these do control the voltage running to sensors and parts ran dirrectly by the ECU so these minor fluctuations in voltage will be noticed in parts that do fine tuning, such as at idle.

If your car is going to be out of commision for a week maybe 2 sending it off to ECMLink for a rebuild would be a good thing. Simple replacement and cleaning shouldn't cost that much and turn around would be quick.

 

[juntjoo]

I have two cars so I have time but not until I try this other isc but isn't there some diagnostic tool that can read such erratic behavior and help narrow down better the possible cause(s) before I go shipping it off?