high idle issue - SRT Forums

vschaos · 04-18-2008, 06:23 PM

Well I went to the new high res, but that code had issues with it leaning out while attempting to drive. Just this evening I had my car back together and I re-burned the older 029v_ngc3 code and burned the old msq...cranked up, but idled high. I have no idea why it is, but I figure its the manifold gasket or a line somewhere? I just received a pm from boostjunkie and he is going to send me the newest fixed hi res code with the ngc on it so will try that tomorrow. I made a log and here is my msq if anyone can take a look. http://vschaos.redlined.org/idleissue.zip

vschaos · 04-19-2008, 03:54 PM

I got the new code from boostjunkie and will be uploading it again...lil tired and gotta get some food. I think my issues with the high idle are due to my battery voltage. When burning firmware it comes back saying 11.0 voltage.....so thats not good. When I reset the pcm and start the car up it idles completely fine. When I blip the gas the idle goes up and hangs. I let it sit for about 10 minutes idling like it should and blipped the gas....came back down as it should have. I attempted to drive and made it about halfway around the block(1/2 mile) and it started it again. So a friend is bringing over his battery charger and I am going to charge it overnight. Its a 1400 cold cranking dry cell battery so its a big battery.

vschaos · 04-19-2008, 11:06 PM

I put the battery charger on the dry cell with a 2 amp load(better) and went to eat....then a movie. I just got back to see that the charger is only showing about halfway charged....so the battery is pretty low. Going to leave it charged over night till about mid day tomorrow and see how it goes. I didnt realize the battery was that low. I hope thats what is causing it to idle high like that at times. It was mentioned also on the extra forums... "Could also be the distributor or ignition table. At high advance you will get a much higher idle. Check the advance at normal idle and high idle." I dont know for sure what he is talking about, but I will try and look over the manual tomorrow to see. Anyone have idea?

2K4NightRiderSRT · 04-21-2008, 03:13 PM

I run 39 degrees at idle, and I idle at ~800 rpm and pull 25-26Kpa of vaccuum.

I would adjust your fuel table in the idle area so you pull the most vaccuum your engine will make at idle. This will probably not match the AFR table in that area, and may be kinda rich. For me, to pull that much vaccuum, I idle at about 12.5-13 AFR. Only till after I checked my engine's timing was I even able to idle at 15-17 AFR. After I corrected my engine's timing, I pulled more vaccuum as well. I used to only get about 28-29kpa.

So yes, it is a combination of both. I'd adjust fuel first because you specifically said it's running lean. Also, when you added the fuel table again, was that table written for the Req_fuel you're currently using? That is important.

Overcome · 04-23-2008, 11:57 AM

I run 12 degrees of advance utilizing the idle advance feature. I have it kick in at a coolant temp of 120 degrees which helps me run more advance on my spark table for cold starts. The stock PCM will run in the 20's for advance during cold starts and taper down to 6-15 degrees (it uses timing to hold idle at a rock solid rpm). Running a high amount of advance at low rpms will cause a high idle as well as a vacuum leak and an over zealous IAC valve. I would go through and double check all settings as I have gotten some weird issues due some numbers seemingly changing themselves.

2K4NightRiderSRT · 04-24-2008, 12:57 PM

Quote: Originally Posted by Overcome

I run 12 degrees of advance utilizing the idle advance feature. I have it kick in at a coolant temp of 120 degrees which helps me run more advance on my spark table for cold starts. The stock PCM will run in the 20's for advance during cold starts and taper down to 6-15 degrees (it uses timing to hold idle at a rock solid rpm). Running a high amount of advance at low rpms will cause a high idle as well as a vacuum leak and an over zealous IAC valve. I would go through and double check all settings as I have gotten some weird issues due some numbers seemingly changing themselves.

How much vacuum do you pull?

I've been playing with my idle timing for a while now and have come to find at about 36-38 degrees and 12-13 AFR, I pull about 24-25Kpa at idle once the engine is warm.

[edit: And that's with an idle in the 700s]

vschaos · 04-24-2008, 02:27 PM

Before the firmware upgrade I was running the 17 degrees of timing at idle and had a 800 degree EGT no problem. I think I am just getting rid of the MS and going SCT. I am getting a SCT PRP package for $600 shipped....even having the 3 bar map and tip sensors thrown in(worth $200 alone) so I cant really complain. I loved the MS, but it can be a pain at times. Thanks everyone for being helpful I really appreciate it.

2K4NightRiderSRT · 04-26-2008, 08:26 AM

Quick update.

Because of the warming weather, I cannot run 39 degrees at idle during the day. I can at night and in the morning... but not at noon. So, since I've discovered this, I've retarded my ignition to about 22 degrees at idle. I still manage to pull 24-25 Kpa once fully warmed up.