Loping Idle, Stalling, Surging

Have a flashing light? Gauges acting funny? Bad idle? Get your problems solved...
Mkweaver1958
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Loping Idle, Stalling, Surging

Postby Mkweaver1958 » Mon Jan 18, 2021 4:33 pm

1990 INDY 3.1
My INDY has developed an annoying habit of having an erratic idle, stalling and power surges.
An AC hose popped and she sucked in some of the 134A and oil which caused this condition.
I've replaced:
IAC
Plugs
Cleaned the EGR
Cleaned the Intake
Any ideas where I need to go next?
It shows NO codes.
Tried running it without the Intake temp sensor and nothing different.
Open to suggestions.
Thanks,
Mark



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3X00-Modified
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Re: Loping Idle, Stalling, Surging

Postby 3X00-Modified » Mon Jan 18, 2021 7:52 pm

Next thing I would test is O2 sensor... That being damaged could cause it to run like that.

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Mkweaver1958
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Posts: 61
Joined: Tue Nov 06, 2018 8:00 am

Re: Loping Idle, Stalling, Surging

Postby Mkweaver1958 » Mon Feb 08, 2021 1:05 pm

I'll give it a shot, but wouldn't the O2 sensor throw a code if it was bad?



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3X00-Modified
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Re: Loping Idle, Stalling, Surging

Postby 3X00-Modified » Mon Feb 08, 2021 3:11 pm

Remember OBDI is a very archaic on boar diagnostic system, it may not throw a code for that even if it is bad.

There are some codes for circuit open or no activity and ones for static readings... pegged rich or pegged lean... If the sensor is still responding but is just way off then the ECU doesn't know that, it will just think it's accurate and incorrectly adjust the fueling for it.




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