major idle problem
Thread Starter
12 Second Club
iTrader: (2)
Joined: Feb 2004
Posts: 1,011
Likes: 0
From: Front Royal, VA
major idle problem What would cause an idle/startup to mysteriously go from perfect to very low at startup(500-700rpm, should be 900-100rpm) eventually it will come up to 800-900. STIT goes to 32g/sec and obviously Idle desired gets maxed out at 40g/sec??? Also when it is doing this the MAP is showing 70-80kPA. Dynamic airflow is also allover the place from 17g/sec to 11g/sec.
This started once I reenabled the maf and closed loop. I did try my open loop tune that worked perfectly the day before and it does the same thing.
Attached is the log when it initially did this:
http://www.hptuners.com/forum/attach...2&d=1148921427
If you want the excel exported file or something else just post up your email and I can send it.
Any ideas? I'm lost, I've never had an idle problem like this.
This started once I reenabled the maf and closed loop. I did try my open loop tune that worked perfectly the day before and it does the same thing.
Attached is the log when it initially did this:
http://www.hptuners.com/forum/attach...2&d=1148921427
If you want the excel exported file or something else just post up your email and I can send it.
Any ideas? I'm lost, I've never had an idle problem like this.
Last edited by Checkmate; May 29, 2006 at 02:36 PM.
Three things come to mind for this situation.
1) Reset the idle trims-pull the battery cable
2) Disable the learning trims, ie make the temp 234+
3) Start Over
If you have already done this, sorry. This always works for me.
1) Reset the idle trims-pull the battery cable
2) Disable the learning trims, ie make the temp 234+
3) Start Over
If you have already done this, sorry. This always works for me.
Sounds like the fueling and/or timing isn't right. When you start it up, it's in open-loop commanding somthing richer than stoich. Once the O2 sensor warm up (timer in PCM runs out), it switches to closed-loop. I bet that's when the idle starts going crazy on you. I'd make sure you're running close to 23~25 degrees in P/N and 30~32 in gear for spark as a starting point for your 'big cam.' Then, get your fuel trims at idle down to -2~0. That's when you can fine tune your idle (adjust TB to get IAC's close to 70, tune RAF, etc.).
Thread Starter
12 Second Club
iTrader: (2)
Joined: Feb 2004
Posts: 1,011
Likes: 0
From: Front Royal, VA
Thanks for the suggestions.
For the aid of anyone else that has the same problem:
I ended up pulling the battery cables, making major adustments to idle timing(more, as in 30ish), leaning out open loop fuel for colder coolant temps and updating the IAC Position vs. Effective Area table several times. Things seem to be better..
Big thanks to RedHardSupra for some other tips also.
For the aid of anyone else that has the same problem:
I ended up pulling the battery cables, making major adustments to idle timing(more, as in 30ish), leaning out open loop fuel for colder coolant temps and updating the IAC Position vs. Effective Area table several times. Things seem to be better..
Big thanks to RedHardSupra for some other tips also.
