ECU Question? Options

[awd4kicks]

If your idle is actually settling down from 1100 to 750 some times, I guess I would need more information on when this surge is happening. Most of the time idle surge is simply caused by a vacuum leak or the idle being set too high, but if the engine is coming down to 750 at a steady rate then that's not it.

More info and we may be able to help.

[BudmannG]

This idle surge happens everytime I start the car in the morning. And I have a slight incline on my driveway. Enough to let roll without e-brake on.

So if I start it first thing in the morning and just barely let it roll. It will surge until the car comes to a complete stop. I pull the e-brake and let it run for about ten minutes. Leave to take my son to school, start rolling back out of drive and it start surging again. Always around 2000 rpm - 2500 rpm up and down, until I come to a stop. Then about thirty seconds after I stop. The idle will settle where it's supposed to be. I go to the stop sign and it does it again, and then might take a little longer to settle idle down.

Now for when the car is warm. Me coming to stop clutch pushed in it will idle at 1100-1200 rpm. Until I come to a complete stop and 30-45 seconds after I stop it will settle at 750-800rpm. This happens all the time.

And last but not least. I don't have an egr, as I am running a JDM engine and cyclone intake.

I hope this helped a little more. I kind of went into a little more detail for you.

[awd4kicks]

OK that helps. It sounds like everything is fine when the car is not moving. There is a sensor that lets the ECU know wheel there is vehicle motion. From your description once the ECU senses that the vehicle is in motion or still in motion, it is not happy with the idsle setting and is trying to correct it.

[BudmannG]

Yes that is what is happening.
So all of it has to do with my idle? My idle is set at 750 rpm. And that's when my logger was working. Now I need a new freaking cable. I've tried to make one myself and that didn't work.

[awd4kicks]

No I'd say you idle is set fine and that all the mechanical parts that control your idle are fine. I'm leaning more toward the ECU being confused about what is a good idle setting when the car is rolling.

You could try raising the idle up a little to see if that compensates enough and keeps the ECU from screwing with the idle while rolling. Just keep in mind the max idle threashhold is about 1500RPM when the car is not moving. above this and the ECU will cause the engine to surge even when it's not moving.

[BudmannG]

It's doing that now, the idle surge. So wouldn't I want to turn the biss in and drop the idle?

[The Iron Goat]

No, what kicks is saying is the ECU thinks the idle is too low, so it keeps trying to rev it up to the proper speed. So if you raise it on your own, the ECU may be happy with the higher setting.

You mentioned that things on your TB were in good order or new. It's possible you got a bad seal around the TB and intake manifold when that work was done. I'm not sure if the failing ECU wouldn't have noticed the leak in it's disabled state, so someone else will have to clear this up. Kind of a "things are screwed up, but the computer is too stupid to know it right now" situation.

[BudmannG]

OK, Everyone can say I told you so! Badbu68 has not returned my ecu yet. And every attempt that I try to get a hold of him he ignores me.
If someone knows him or where he lives I would appreciate it if you could stop by and pickup my ecu.
This is what I sent him today and he blatantly ignored me:
I want you to take my ecu to Brett (Turbohcar) at:
Bill Smith Auto Parts
Brett
2102 South Bunn Street
Bloomington, IL 61701

I don't care if it is done or not just take it to Brett and drop it off. Let me know if you are going to do this so I can tell him to expect you, Thank you.
I hope this is not asking to much of you Brett. I just didn't know anyone else in Bloomington area who I could trust with this.

[BudmannG]

Bump!

[BudmannG]

The last thing he told me was he broke the tip on his solder iron. Easy fix right? I feel like there is something amiss. When I met him he seemed cool to me. That's why I left it with him. And now I'm going on 4 weeks without it.
I don't like running his name in the dirt. But when I see him on I pm him. I've even tried calling him when I see him on and nothing. I just want him to let me know what is going on. It has been long enough to get a solder tip from radio shack and solder 3 caps in, At least I think.

[badbu68]

Your ecu will be dropped off in the morning, it was fixed last week. My bad.

[MidwestDSM]

wow, I just saw this thread. Badbu is a standup guy and I know for a fact he wouldn't pull any shady shit with anyone, I'm glad this is bieng resolved.

[BudmannG]

Your ecu will be dropped off in the morning, it was fixed last week. My bad.

Thank you!