Cold Start = Fast Idle ?
11-01-2003, 06:48 PM
#1
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Car: 86 Z28
Engine: 305TPI stock
Transmission: TH700R stock
Cold Start = Fast Idle ?
In my ongoing pursuit of TPI happiness my latest problem is a cold idle of around 1500-1300 in park. When it's cold it requires a foot on the gas to get going but after a few seconds will idle on its own just around 15 grand or so. Sometimes the idle bounces 100rpm or so. When it finally gets up to around 220-200* it will start up fine and idle at 750* in park 500* in drive. At first i looked for vac leaksand replace some cracked hard lines. Then I cleaned the iac and throttle body. Then i replaced the iac. I replaced the CTS and O2 sensor as well. I have reset the IAC and TPS numerous times always with the same results. The motor runs grreat hot, just a real high idle when its cold.
Any more suggestions?
I've considered swapping in a newer chip maybe an 88 or something with a similar stock setup. Other than that I'm out of ideas.
Any more suggestions?
I've considered swapping in a newer chip maybe an 88 or something with a similar stock setup. Other than that I'm out of ideas.
11-01-2003, 08:56 PM
#2
LA,
That's relatively normal. Cold starts will set the target idle RPM at 1,400-1,500 RPM. As the coolant temperature increases, the target idle RPM should decrease. If yours will not gradually lower the RPM as the engine temperature increases, you might want to test the resistance of the CTS.
What you are describing sounds just fine, however.
That's relatively normal. Cold starts will set the target idle RPM at 1,400-1,500 RPM. As the coolant temperature increases, the target idle RPM should decrease. If yours will not gradually lower the RPM as the engine temperature increases, you might want to test the resistance of the CTS.
What you are describing sounds just fine, however.
11-01-2003, 11:47 PM
#3
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Car: 1989 TransAm GTA
Engine: One sweet modified 355 TPI.
Transmission: The kind that shifts....
That sounds good then. Because my car does the fast idle thing. However, it'll idle where ever I put it, but it does idle around 1,000rpm to 1,200rpm in nuetral when cold. Sometimes a quick rev will make it go away.
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