Surging Idle at startup
09-10-2014, 08:24 PM
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Car: 88 Camaro SC
Engine: 350
Transmission: T-5
Axle/Gears: 3.42 POSI
Surging Idle at startup
I've been fighting a start up idle issue that I can't seem to kick. Upon initial start up, the engine revs up to about 1400, then drops to about 850. From there it surges up and down from as low as 550 to about 1100 RPMs. This usually continues for a few minutes or until I start driving. The WB shows the AFR going rich when the RPMs drop, and lean when they rise. I'm using EBL by the way. I attached a log (extension changed to .txt to post) of a start up from earlier today showing the issue. Any suggestions on solving the issue?
09-11-2014, 07:56 AM
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Car: check
Engine: check
Transmission: check
Re: Surging Idle at startup
Note closer to the end of the log that the IAT is moving between 82* and 90* F. At first the IAT and CTS match, which is good on a cold start. There may be a connector issue or the IAT is bad.
Toward the beginning of the log the IAT holds at 83* F, the area that is going lean is in the 1000 to 1100 RPM and 28 KPa area. Add some to the VE table in that area and blend in.
The commanded AFR stays in the 11.1:1 to 11.5:1 area, so it likely isn't that.
RBob.
Toward the beginning of the log the IAT holds at 83* F, the area that is going lean is in the 1000 to 1100 RPM and 28 KPa area. Add some to the VE table in that area and blend in.
The commanded AFR stays in the 11.1:1 to 11.5:1 area, so it likely isn't that.
RBob.
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