idle problems
Thread Starter
Drifting
Joined: Nov 2014
Posts: 1,977
Likes: 109
From: Switzerland
idle problems
four years ago i put a centri blower on my 1999 c5 and tuned it myself. i never had any idling issues before, but last spring the car developed slight hunting that slowly got worse over time to the point where it would be undrivable (no changes to the tune), it would die at every stop light and even when getting off the gas while driving. this was in closed loop only, when cold on start up idle was fine and even if warm for a short while.
i repaced the pcv valve, no change, i put a fixed restrictor in, no change, i took it off (blocked the port), no change, i put in new oxygen sensors (one was getting a little slow anyway), no change, they now switch beatifully. i chaged back to tr6 plugs from br7ef (they looked good) and that fixed the issue in drive (so much concerning retracted plugs). not in park/neutral however. engine still hunts, a little less, though, it doesnt die. car behaves the same in cold and hot weather, btw.
where to lok next before i start making fancy changes to my tune? tps? doesnt make much sense.
i repaced the pcv valve, no change, i put a fixed restrictor in, no change, i took it off (blocked the port), no change, i put in new oxygen sensors (one was getting a little slow anyway), no change, they now switch beatifully. i chaged back to tr6 plugs from br7ef (they looked good) and that fixed the issue in drive (so much concerning retracted plugs). not in park/neutral however. engine still hunts, a little less, though, it doesnt die. car behaves the same in cold and hot weather, btw.
where to lok next before i start making fancy changes to my tune? tps? doesnt make much sense.
Melting Slicks
Joined: Sep 2008
Posts: 3,127
Likes: 799
From: Espanola New Mexico
I would clean the throttle body and MAF sensor, also do a search for idle relearn procedure. I have a 97 coupe with A&A kit with the vortech supercharger and experienced the occasional shutting down usually happened after opening it up and then coming to a stop light, the idle would just drop down to nothing and car would die, started right up afterwards every time. Hope this advise helps.
Thread Starter
Drifting
Joined: Nov 2014
Posts: 1,977
Likes: 109
From: Switzerland
i forgot to mention: no maf, no ltfts. filter is new and huge (diy). the real question is: whats different when in park/neutral vs. drive? i dont think the bushings behave differently. btw, idle speed is set at 650 for both and no, increasing it doesnt make a difference.
the relearn subject is confusing. i see anything from pulling fused to car does it on its own. what do you have in mind exactly?
the relearn subject is confusing. i see anything from pulling fused to car does it on its own. what do you have in mind exactly?
Last edited by romandian; Nov 13, 2018 at 03:24 AM.
Melting Slicks
Joined: Sep 2008
Posts: 3,127
Likes: 799
From: Espanola New Mexico
I did the relearn procedure that calls for pulling fuses, starting the car, turning of, reinserting the fuses, starting the car letting it come up to about 176 degrees, and going for a 30 mile ride that includes varying speeds. The exact steps of the idle relearn procedure are on the internet, I performed this procedure and it helped my 97 coupe.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Drifting
Joined: Jul 2011
Posts: 1,599
Likes: 398
From: Boise, ID
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
C5 of Year Finalist (appearance mods) 2019
Have you lubricated your bpv? I had neglected this on my car, disassembled, cleaned, lubricated and put it back together. I also replaced he hose to bpv not sure which made the biggest difference but one of them helped a lot for my idle issues.
Last edited by tommypenguin; Nov 15, 2018 at 04:27 AM.
Thread Starter
Drifting
Joined: Nov 2014
Posts: 1,977
Likes: 109
From: Switzerland
bpv=blow off valve? how did you lubricate it and why? i suspect it was leaking. but if idle is good in drive and only goes bad in part/neutral?
Last edited by romandian; Nov 18, 2018 at 06:00 AM.
Drifting
Joined: Jul 2011
Posts: 1,599
Likes: 398
From: Boise, ID
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
C5 of Year Finalist (appearance mods) 2019
Bpv = blowoff valve just kept selecting the wrong acronym from my phone, hardly anyone recircs with our cars so it's just a bov..
To lubricate I unscrewed the valve pulled out the spring and piston. Cleaned both, and bought a specific lube on Amazon made by turbosmart.
My condition was that I had an idle hunt issue where when driving when putting into neutral as rpms would return to set idle it would fall below where it died a few times or rpms would bounce back and drop in a loop. Sometimes it would return to set idle point other times is would hunt.
Here is a link to a thread about cleaning bpv.
https://www.corvetteforum.com/forums...-and-vids.html
To lubricate I unscrewed the valve pulled out the spring and piston. Cleaned both, and bought a specific lube on Amazon made by turbosmart.
My condition was that I had an idle hunt issue where when driving when putting into neutral as rpms would return to set idle it would fall below where it died a few times or rpms would bounce back and drop in a loop. Sometimes it would return to set idle point other times is would hunt.
Here is a link to a thread about cleaning bpv.
https://www.corvetteforum.com/forums...-and-vids.html
Thread Starter
Drifting
Joined: Nov 2014
Posts: 1,977
Likes: 109
From: Switzerland
im still strugling with this. i will probably have to try and tune it out. but im reluctant to cover up some "hardware" issue with the tune, as this really came gradually from nowhere.
Pro
Joined: Feb 2014
Posts: 714
Likes: 106
From: England
Difference between park and drive is the load on the engine as you release the throttle.
Sounds like an air leak developed and has gotten worse. What does your fuel trim and AFR look like as its stalling?
Sounds like an air leak developed and has gotten worse. What does your fuel trim and AFR look like as its stalling?