Idle Surge problem! Can't figure it out and I've searched!!!!!

[1997_GST]

Okay, so i have a 97 GST that i did a 5-speed swap on. The car runs, I drove it from Mansfield, TX to Electra, TX, about a 2.5 hour drive,. The car has a idle surge. And it's annoying and makes me mad!!! It had a SAFC hooked up to it but i removed it to see if that would change anything and it didn't. I've tried different ecus and still does it.

The surge is like between 1100 rpm and 1800 rpm... and if i give it gas it revs fine but after i let off the throttle it sticks at like 2500 rpms for a split second then goes back to the surging...

If i drive the car and like barley hold it in 1st gear it like changes the throttle on it's own...but does fine while normal driving at highway speeds...

ANY HELP WOULD BE APPRECIATED AND REMEMBER I DID SEARCH ON THIS AND COULDN'T FIND ANYTHING THAT MATCHED EXACTLY MY PROBLEM....

THANKS!!!!!

 

[Absit]

You said you searched, what all have you actually tried so far?

Searching "idle surge" yields plenty of results. They all point to testing the ISC, TPS/Idle Switch, checking tension on the throttle cable, checking for boost leaks, cleaning the throttle body..

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge) You searched i did this several times on idle inthe past week, dsm idle, i used google.com


Here you go.

 

[razrman8]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge) You searched i did this several times on idle inthe past week, dsm idle, i used google.com


Here you go.

^^^+1
also +1 on throttle bbody clean... and checking to see if isc is good isnt hard at all 5 mins

 

[92AWDHX40]

You wont find a exact answer to your question youll have to read, and try different things.

 

[1997_GST]

How do I test the ISC and TPS? My CEL is on but only one code was pulled p1105 fuel pressure solenoid... but im not sure why...

 

[Absit]

You could read the link already posted, or you could check out vfaq.com or plymouthlaser.com.

 

[92AWDHX40]

The thread is up there look at it and read it, check vfaq.com lot of resources to help you.

 

[1997_GST]

I'm in the process of reading it... the ISC is the one on the back of the throttle body correct.. not the one on the front held by 2 8mm bolts and adjustable?

 

[Absit]

The one in front is the TPS. Do you have a manual?

 

[liquidz28]

easy things first,
set your BISS down to where the low part of your idle is at about 790-850rpm at operating temp.
shut the car down remove your idle control valve (isc) it is a 2 screw attatchment just under your throttle body and inspect it for damage/carbon deposits. have an assistant turn the ignition to the "on" position but do not start, the plunger "should" move in and out when this happens, if so clean and reinstall, if no movement present remove and replace. The ISC is natoriously an issue, my engine has had ALL electrical replaced 38k miles ago and i have allready gone through 1 ISC the quality of parts just arent what they where 20 years ago.
i am 80% positive this is your problem.

 

[boosted86]

surge is caused by the ecu not getting a steady airflow metering. if the car is at operating temp disconnect the isc and see if fixes the problem. make sure you have no boost leaks ( boost leak test)

p.s' an easy way to test your isc without a voltmeter is to remove it from the throttle body ( two 8mm screws) with the connector still attached and have some one turn the ignition to the on position. if the tip of the isc retracts( when the ignition on) completely and than extends completely it is functioning properly. if it just buzzes and shakes then the isc is faulty.

 

[1997_GST]

Okay i appreciate the info, I will check tonight when I get off work at midnight...check back and i will have info on how it went testing the ISC.

and i do have a service manual but its in mansfield tx 2.5 hours from where i currently live -__-

 

[Absit]

We gave you a LOT more to do than just testing the ISC, do it all, then report back.

 

[liquidz28]

surge is caused by the ecu not getting a steady airflow metering. If the car is at operating temp disconnect the isc and see if fixes the problem. Make sure you have no boost leaks ( boost leak test)

p.s' an easy way to test your isc without a voltmeter is to remove it from the throttle body ( two 8mm screws) with the connector still attached and have some one turn the ignition to the on position. If the tip of the isc retracts( when the ignition on) completely and than extends completely it is functioning properly. If it just buzzes and shakes then the isc is faulty.

ya wut he saidrofl

 

[boosted86]

easy things first,
set your BISS down to where the low part of your idle is at about 790-850rpm at operating temp.
shut the car down remove your idle control valve (isc) it is a 2 screw attatchment just under your throttle body and inspect it for damage/carbon deposits. have an assistant turn the ignition to the "on" position but do not start, the plunger "should" move in and out when this happens, if so clean and reinstall, if no movement present remove and replace. The ISC is natoriously an issue, my engine has had ALL electrical replaced 38k miles ago and i have allready gone through 1 ISC the quality of parts just arent what they where 20 years ago.
i am 80% positive this is your problem.

a moving isc does not mean the valve is functioning. which is why i re described what you already mentioned. and a good/bad isc will always have carbon deposits on it.

ps. biss asjutment will not drop engine speed on a surging motor

 

[1997_GST]

yah i was about to say that... i tried adjusting the biss screw and nothing happens due to surging....

 

[92AWDHX40]

Again the link on idle surge have you tire everything yet. Test your isc, do boost leaks, so many things to look at. Pick one and go from there.

 

[1997_GST]

okay well i took my throttle body off and took the isc out and turned the key to the on position and it did nothing but vibrated a little bit... so im waiting for my buddy to ship me one and see if that fixes it...

 

[boosted86]

okay well i took my throttle body off and took the isc out and turned the key to the on position and it did nothing but vibrated a little bit... so im waiting for my buddy to ship me one and see if that fixes it...

yea if all it did was vibrate the coils inside are toast.. replacing it should fix your problem

 

[GST98 PR]

im a little too late but here are two links that helps too :




IdleSpeed - DsmWiki


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html




hope this helps you or somebody else

 

[1997_GST]

hey your not too late.. all info helps! thanks!

 

[GST98 PR]

i forgot to add this one too :





Stealth 316 - ISC Servo Motro




^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[Jesse__c]

where do i get an ISC from?

 

[GST98 PR]

where do i get an ISC from?

if your lucky enough you can get it on a yunkyard, on the dealer (OEM), or autozone i think (not exactly sure about autozone if someone knows correct me pls ) or any local autopart store....oh check ebay too and the clasifieds