Need help with idle!
Thread Starter
Pro
Joined: Jun 1999
Posts: 525
Likes: 0
From: San Jose, Ca
Need help with idle!
Hey guys,
I'm running out of things to try and my idle is still very rough. It usually, starts to act up once the car reached about 200 degs. I get a pretty bad surging, it doesn't die but it gets close. Here's what I've done so far:
1. Removed and cleaned the throttle body.
2. Replaced the O2 sensor.
3. Adjusted the TPS to 0.54V
4. Replaced the IAC sensor.
5. Checked cap, rotor and plugs all look good.
6. Checked resistance on injectors, currently the 4 that are closest to the front of the car are at about ~12ohms, the 4 to the rear are at about ~17 ohms. (thinking this might be an issue, but not sure if it would cause the surging)
So what's next? I've seen mention of the ECM? Is this the computer module? How can I check it?
Could the injectors cause this senario?
Any tips would be appreciated, not sure what else to do.
I'm running out of things to try and my idle is still very rough. It usually, starts to act up once the car reached about 200 degs. I get a pretty bad surging, it doesn't die but it gets close. Here's what I've done so far:
1. Removed and cleaned the throttle body.
2. Replaced the O2 sensor.
3. Adjusted the TPS to 0.54V
4. Replaced the IAC sensor.
5. Checked cap, rotor and plugs all look good.
6. Checked resistance on injectors, currently the 4 that are closest to the front of the car are at about ~12ohms, the 4 to the rear are at about ~17 ohms. (thinking this might be an issue, but not sure if it would cause the surging)
So what's next? I've seen mention of the ECM? Is this the computer module? How can I check it?
Could the injectors cause this senario?
Any tips would be appreciated, not sure what else to do.
Thread Starter
Pro
Joined: Jun 1999
Posts: 525
Likes: 0
From: San Jose, Ca
I haven't set the minimum air idle yet, I'm assuming this is when you jumper the A/B connection under the dash and unplug the IAC. If this was off, could it cause the surging?
I thought about the EGR, but to do that do I have to remove the plentum and runners?
I thought about the EGR, but to do that do I have to remove the plentum and runners?
Pro
Joined: Oct 2002
Posts: 586
Likes: 0
From: Schmuckville SA
The car idles ok when cold? Have you checked to make sure car is
in open or closed loop? Injector balance could be a possibility in
an older car too.. If it idles ok from cold start up to 200 degrees,
maybe your coolant temp sensor is getting whacky.. Lastly, at what
rpm does the car start to hunt around and sputter???
in open or closed loop? Injector balance could be a possibility in
an older car too.. If it idles ok from cold start up to 200 degrees,
maybe your coolant temp sensor is getting whacky.. Lastly, at what
rpm does the car start to hunt around and sputter???
Thread Starter
Pro
Joined: Jun 1999
Posts: 525
Likes: 0
From: San Jose, Ca
The car does idle ok when cold, but starts to surge around 200 deg. How do I check if the car is in open or closed loop?
As far as the RPM, it surges typically around 600 to 900. After you pass about 900 rpm it starts to mellow out.
The funny thing is there are some times when it seems fine, very intermitent. I'd say it does it about 75% of the time.
As far as the RPM, it surges typically around 600 to 900. After you pass about 900 rpm it starts to mellow out.
The funny thing is there are some times when it seems fine, very intermitent. I'd say it does it about 75% of the time.
Racer
Joined: Jun 2004
Posts: 391
Likes: 0
From: Lisle IL
CI 6-7-8-9-10 Veteran
Black'69,
I am having the same problem with my '88. Please see my post.
http://forums.corvetteforum.com/showthread.php?t=857233
Let's keep in touch until we can figure this thing out.
Thanks,
Bob
I am having the same problem with my '88. Please see my post.
http://forums.corvetteforum.com/showthread.php?t=857233
Let's keep in touch until we can figure this thing out.
Thanks,
Bob
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Racer
Joined: Jun 2004
Posts: 391
Likes: 0
From: Lisle IL
CI 6-7-8-9-10 Veteran
Did you see this thread? http://forums.corvetteforum.com/showthread.php?t=860522
Have you tried changing you TPS to .48?
Bob
Have you tried changing you TPS to .48?
Bob