High Idle on Cold Start-up
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CF Beginner
Joined: Dec 2022
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High Idle on Cold Start-up
I have a 95 Tahoe with the TBI 350 in it. I have a random high idle on cold start up. I cannot seem to figure it out. It is definitely not a vacuum leak. I put a scanner on it during the last start up and logged the data. The IAC is opening all the way and slowly comes down. Another thing I noticed is the BLM is commanding a lean condition. Any ideas?
CF Veteran
Joined: May 2011
Posts: 1,578
Likes: 302
From: Central Iowa
1) IAC movement sounds normal for start up conditions.
2) Remove the air cleaner and check the injectors for leaking fuel during the fuel line priming at key on.
3) Check the MAP sensor reading KOEO - if it doesn’t read atmospheric pressure on live data (or voltage equivalent if using meter) it’s skewed and needs replacement.
4) Check the ECT at cold start - it should reflect ambient temperature within 5 degrees.
2) Remove the air cleaner and check the injectors for leaking fuel during the fuel line priming at key on.
3) Check the MAP sensor reading KOEO - if it doesn’t read atmospheric pressure on live data (or voltage equivalent if using meter) it’s skewed and needs replacement.
4) Check the ECT at cold start - it should reflect ambient temperature within 5 degrees.
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