SSBoy

Heres my situation:
Within the last month my idle has been a biatch. I start the car up in the morning and it will idle at 1K, put it in reverse and shoots up to 1200, put it back in drive where it will start surging from 1100-550(for twenty seconds). Its really getting frustrating, i mean this cam is not big at ALL AND the car has pcm tuning! After like 20 seconds the car will idle fine, but i DO NOTICE that when i come to a stoplight my idle will drop to 1K THEN about two-three seconds later it will drop to its idle where its suppose to be which is 850. Why IS IT DOING THAT ? <img src="images/icons/confused.gif" border="0"> After about a minute of warming the car up, it wont surge at all, but it WILL still do what i said earlier (about coming to a stop)

Heres what I think could be the culprit. I have disc. my battery quite a few times recently and am wondering if my pcm is going nuts because of it. Maybe the PCM is loosing its meomery of idle?? Now im in the situation where i think to myself,
1.) do I do an idle relearn
or <img src="images/icons/confused.gif" border="0">
2.) do i drill out the throttle body

I tend to go with scenario 1 because my car use to idle very very well, with very very little surging. (remember i mentioned that my idle started acting weird the past month)

I autotapped the car and the IAC counts are coming in at over 100 in Drive and Park. its rather weird that even before this recent ordeal my IAc counts were still very high yet the car did not surge that much at all. <img src="images/icons/confused.gif" border="0"> <img src="images/icons/confused.gif" border="0"> Note: I did just install a MMS ported Throttle body last week, so if that means anything.

thanks, I appreciate the feedback and look
forward to getting my car back to its regularly scheduled idle <img src="gr_grin.gif" border="0">

HWYRIPR

iTrader: (9)

Hey SSSBoy,I'm no expert but I had a problem like that with my SS and somehow I had lost the EGR gasket when doing the free mod.Probally not but might want to check!Hope you figure it out! <img src="gr_sad.gif" border="0">

Jason99T/A

iTrader: (21)

Check the EGR seal like posted above. If that looks fine, I would do the idle relearn procedure. Also, make sure your TB is tight after you installed it...LOL

Tin Indian

If you dont have a vacuum leak at the EGR connection on the intake manifold, I would bet that the problem stems from the new MMS ported throttle body. One of two things.

1. The throttle plate is not set properly (at idle). Too far closed or too far open when at idle. About the only thing you can do there is take the TB off and shine a light into it. See how far the butterfly is open (by how much light shines through). Then look at your old TB (or someone elses). See how far that butterfly valve is open. Adjust the set screw on your new TB so it is open very close to a factory preset TB. (make sense)

2. Your throttle position sensor is not set right. It should be reading about .6 volts when the throttle is closed against the idle stop. If the voltage is way off, it will cause idle problems. My guess is that the throttle stop is not set right. If your throttle plate is closed too far or open too far (against the idle stop), the IAC valve will have big problems stabilizing your idle speed, thus cousing surging and idle speed "hunting".

Good luck,
Ron

SSBoy

Okay thanks everyone for the replies. I checked the EGR and everything looks good on there. I checked the TB and everything seems to be snug and tight. I'll start by doing an idle relearn procedure tomorrow and if that doesn't work then I will have to pull of the TB and inspect it. When I installed the TB i should have made sure that the set screw was at the same exact location/angle as my original TB. <img src="graemlins/gr_judge.gif" border="0" alt="[judgement]" />

Since I already had an eratic idle before this MMS TB, I tend to believe that I must either do a re learn procedure, or drill it out. Im gonna do a re-learn procedure and start from there.

thanks everyone for your help.
jack

Pro Stock John

iTrader: (34)

Make sure the battery cables are on tight, sometimes if they are not, the pcm will reset when the car sits.

Sounds like the blade in the new TB is cracked differently, or the hole is a different size.

Terry Burger

iTrader: (4)

I bet your EGR valve is bad. There is a TSB on it at the dealership. Free repair!

Tin Indian

If everything else checks out OK, Terry may be right. A stuck open EGR valve will couse serious idle problems.

If your throttle blade is set like the stocker, I would at least check the idle voltage on the throttle position sensor (TPS). Again, if its way off, your idle will be bad. About 0.6 volts is what you need when idling....

Ron,

SSBoy

Ron
Terry
Pro Stock John


I'll go out and A-tap it this morning to see what my TPS voltage is. Im gonna look a little closer at the EGR situation too. Thanks for the replies

SSBoy

I cured the idle! <img src="gr_grin.gif" border="0"> I did a re-learn procedure and after 20 minutes, i switched the car from drive and neutral, park and drive, etc..and it idled beautifully, like it should <img src="gr_grin.gif" border="0"> Just wanna tell everyone thanks for the replies and effort. Fixing Little 'bugs' like this make it all worth while. It actually gets me thinking about modding the car more...ahhahahaa <img src="gr_grin.gif" border="0">

JohnR

iTrader: (1)

This was a fun post to read!!!
Hot Rodding is a "Fever", and either you have it or you don't.
Ordinary folks will never understand why we think the way we do.

ie;
"I love this car, SLP REALLY ROCKS!"

"I just installed this new cam, What a piece of $h!T!"

"Hey man, I just figuerd out how to make this work, COMP CAMS RELLY ROCKS!"

"Now I think I'll try those new MTI heads!"

...and on, and on, and on.....
You got a love it! I do.

Glad to hear that you fixed it and that it was actually very easy. I'll remember that. Thanks for sharing it with us. It really feels good when you can solve a problem with the help of some friends.

John

Dave Jones

How does one do the "idle relearn procedure"?

Here's why I'm asking. I posted questions about this before, but no one has come up with a definitive answer. Sometimes my 2002 Z28 runs very rough when I first start it up. It always seems to happen when the car has been driven and then rested for about 20 minutes. After some five to fifteen seconds, the car will go back to running normally, and it will happen VERY QUICKLY.

Any ideas?

Jason99T/A

iTrader: (21)

I'm glad you got the problem fixed Jack. Go enjoy the car again. <img src="gr_grin.gif" border="0">

Jason

SSBoy

[quote]Originally posted by Dave Jones:
<strong>How does one do the "idle relearn procedure"?


</strong><hr></blockquote>

Dave,
If you go to the other board..(ls1.com) looked under Elmer Boggs' Signature. It has an idle re-learn procedure right there. Thats the one I used. Sorry, i don't know how to do a hyperlink with that <img src="gr_images/icons/wink.gif" border="0">