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can't adjust idle because of ECU interference.

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Old 08-18-2002, 11:49 AM
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can't adjust idle because of ECU interference.

I have a 98. I can't adjust the idle because the ECU keeps turning it back down, or up.

I tried turning that big plastic screw method to up my idle a bit. It worked for like 30 secs, then the idle self adjusts and comes down. Several years ago, I even went to the dealer to raise my idle. They even connected the OBDII tool(dont know if it Consult II) to try to raise the idle, but it didnt work. Well, it did work for like 10 min, but the idle always went back down to factory setting.

What could be causing this? Anyone had similar problems? I would like to raise the idle to around 800, because now with my budget ypipe, when I'm sitting in traffic with the AC on, the car vibrates a bit.
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Old 08-18-2002, 12:02 PM
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Re: can't adjust idle because of ECU interference.

Originally posted by hokiemax
I have a 98. I can't adjust the idle because the ECU keeps turning it back down, or up.

I tried turning that big plastic screw method to up my idle a bit. It worked for like 30 secs, then the idle self adjusts and comes down. Several years ago, I even went to the dealer to raise my idle. They even connected the OBDII tool(dont know if it Consult II) to try to raise the idle, but it didnt work. Well, it did work for like 10 min, but the idle always went back down to factory setting.

What could be causing this? Anyone had similar problems? I would like to raise the idle to around 800, because now with my budget ypipe, when I'm sitting in traffic with the AC on, the car vibrates a bit.
What procedure did you use to adjust the idle? Was the TPS disconnected?
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Old 08-18-2002, 12:19 PM
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Re: Re: can't adjust idle because of ECU interference.

Originally posted by iwannabmw


What procedure did you use to adjust the idle? Was the TPS disconnected?
I accidentally raised my idle once by tightening the cable that goes from the accelerator to the throttle body. If it's too tight though, you could snap the cable when you floor it I think.
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Old 08-18-2002, 12:43 PM
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Re: can't adjust idle because of ECU interference.

Originally posted by hokiemax
I have a 98. I can't adjust the idle because the ECU keeps turning it back down, or up.

I tried turning that big plastic screw method to up my idle a bit. It worked for like 30 secs, then the idle self adjusts and comes down. Several years ago, I even went to the dealer to raise my idle. They even connected the OBDII tool(dont know if it Consult II) to try to raise the idle, but it didnt work. Well, it did work for like 10 min, but the idle always went back down to factory setting.

What could be causing this? Anyone had similar problems? I would like to raise the idle to around 800, because now with my budget ypipe, when I'm sitting in traffic with the AC on, the car vibrates a bit.
What does a auto 98 max idle at when new? like 800-900 right? So your idle is lower then it should be correct? To me it sounds like you have a problem and raising your idle is just going to cover the problem up. If I was you I would clean your throttle body out and then replace your PCV valve. If you allready did this stuff then I don't know, maybe you need new spark plugs or something.
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Old 08-18-2002, 01:38 PM
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Re: Re: can't adjust idle because of ECU interference.

Originally posted by emax95


What does a auto 98 max idle at when new? like 800-900 right? So your idle is lower then it should be correct? To me it sounds like you have a problem and raising your idle is just going to cover the problem up. If I was you I would clean your throttle body out and then replace your PCV valve. If you allready did this stuff then I don't know, maybe you need new spark plugs or something.
I've never cleaned my throttle body in 120k miles.
PCV valve was changed around 50k ago.
I dont remember what my max idled when she was new, but it wasn't 800-900. I dont remember it being that high. I think it was around 650-700. When the AC is on, the idle does go up to around 800. Normally that is good enough, but with aftermarket y, there is a slight vibration, so I was thinking about raising it to around 900. MY gear is in D all this time. Without the AC, the car sits perfectly still at D. Amazing for a car with 120k miles.

Procedure I followed to try to raise the idle.

1. Start the car.

2. Put the car in D, have a friend stepping on the brake so the car doesnt run me over!

3. Turn the plastic screw counter clock wise. This seemed to work for a minute, but the idle came back down..


* TPS wasn't disconnected. Does it have to be?
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Old 08-18-2002, 06:34 PM
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Re: Re: Re: can't adjust idle because of ECU interference.

Originally posted by hokiemax


I've never cleaned my throttle body in 120k miles.
PCV valve was changed around 50k ago.
I dont remember what my max idled when she was new, but it wasn't 800-900. I dont remember it being that high. I think it was around 650-700. When the AC is on, the idle does go up to around 800. Normally that is good enough, but with aftermarket y, there is a slight vibration, so I was thinking about raising it to around 900. MY gear is in D all this time. Without the AC, the car sits perfectly still at D. Amazing for a car with 120k miles.

Procedure I followed to try to raise the idle.

1. Start the car.

2. Put the car in D, have a friend stepping on the brake so the car doesnt run me over!

3. Turn the plastic screw counter clock wise. This seemed to work for a minute, but the idle came back down..


* TPS wasn't disconnected. Does it have to be?
Try this procedure, it's paraphrased from the one in the book:
1. Make sure car is warmed up fully.
2. Disconnect TPS.
3. Start car and rev engine 2-3 times to 2000-3000 rpm. Then let idle stabilize.
4. Adjust idle to speed desired.
5. Stop engine
6. Reconnect TPS
7. Start car and rev as in step 3
8. Is the idle the one that is desired?

My guess is that with the TPS connected, you're fighting the ECU when you're trying to adjust the idle, it's trying to go back to what it knew. By disconnecting the TPS, you must be telling the ECU to stay out of it. After the adjustment, and the TPS is reconnected the ECU thinks that this is the idle and will maintain that now. If you use the above procedure, I think you'll have better results.

Note: Do not disconnect or connect the TPS with the engine running, it can cause voltage spikes.
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Old 08-18-2002, 06:58 PM
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Re: Re: Re: Re: can't adjust idle because of ECU interference.

Originally posted by iwannabmw


Try this procedure, it's paraphrased from the one in the book:
1. Make sure car is warmed up fully.
2. Disconnect TPS.
3. Start car and rev engine 2-3 times to 2000-3000 rpm. Then let idle stabilize.
4. Adjust idle to speed desired.
5. Stop engine
6. Reconnect TPS
7. Start car and rev as in step 3
8. Is the idle the one that is desired?

My guess is that with the TPS connected, you're fighting the ECU when you're trying to adjust the idle, it's trying to go back to what it knew. By disconnecting the TPS, you must be telling the ECU to stay out of it. After the adjustment, and the TPS is reconnected the ECU thinks that this is the idle and will maintain that now. If you use the above procedure, I think you'll have better results.

Note: Do not disconnect or connect the TPS with the engine running, it can cause voltage spikes.
thanks man!! I'll try that tomorrow and see what happens
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Old 08-18-2002, 09:23 PM
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hokie....

The y pipe should not make your car vibrate.

Did you check that first?


Might be a fitment issue with the Y.

BTW, how is the kit doing...how many bottles you fill so far?

DL
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Old 08-18-2002, 09:27 PM
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I have an 02. I raised the idle from 625RPM ro 675RPM with a Consult II. The change seems to have stayed.

Stereodude
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Old 08-18-2002, 10:20 PM
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Re: hokie....

Originally posted by dlicari
The y pipe should not make your car vibrate.

Did you check that first?


Might be a fitment issue with the Y.

BTW, how is the kit doing...how many bottles you fill so far?

DL
It only vibrates when the AC is on and when I'm idling in D. Otherwise, it's perfect. When I had my stillen y, it did the same thing too. But on the stillen one, I know it was touching something, so it was vibrating REALLY bad.. But the budget Y I have now, the car doesnt shake at all, unless i'm idling in D with the AC on. And even then, it's not too bad.. But since I got a set of ramps now, I'll check the fitment of the ypipe in couple days.

The kit is doing great!! hahaha. I've gone through one bottle now. And guess what, I upgraded to a 70 shot, and I'm runnin blind!!

I"m using a 042 jet for nos, and 032 for the feul Tee. I know the combination stated in the manual for a 70 shot is .036 NOS and .042 fuel Tee, but SR20DEN told me to use .042/.032, so thats what I'm using. But I havent sprayed with these settings yet. Will post again after I do that.
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Old 08-18-2002, 11:45 PM
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Re: Re: Re: Re: can't adjust idle because of ECU interference.

Originally posted by iwannabmw


Try this procedure, it's paraphrased from the one in the book:
1. Make sure car is warmed up fully.
2. Disconnect TPS.
3. Start car and rev engine 2-3 times to 2000-3000 rpm. Then let idle stabilize.
4. Adjust idle to speed desired.
5. Stop engine
6. Reconnect TPS
7. Start car and rev as in step 3
8. Is the idle the one that is desired?

My guess is that with the TPS connected, you're fighting the ECU when you're trying to adjust the idle, it's trying to go back to what it knew. By disconnecting the TPS, you must be telling the ECU to stay out of it. After the adjustment, and the TPS is reconnected the ECU thinks that this is the idle and will maintain that now. If you use the above procedure, I think you'll have better results.

Note: Do not disconnect or connect the TPS with the engine running, it can cause voltage spikes.
You're either VERY good, or quoting from the Chilton's manual.

That's exactly what it says to do.

IanS
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Old 08-19-2002, 06:23 AM
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Re: Re: Re: Re: Re: can't adjust idle because of ECU interference.

Originally posted by iansw


You're either VERY good, or quoting from the Chilto's manual.

That's exactly what it says to do.

IanS
That was pretty much a quote, note the first sentence:
"Try this procedure, it's paraphrased from the one in the book: "
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Old 08-19-2002, 08:00 AM
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Re: Re: Re: Re: Re: Re: can't adjust idle because of ECU interference.

Originally posted by iwannabmw


That was pretty much a quote, note the first sentence:
"Try this procedure, it's paraphrased from the one in the book: "
Doh! Didn't see that part....
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