coolant sensor ie. rough idle ??
Thread Starter
Intermediate
Joined: Oct 2003
Posts: 42
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From: San Lorenzo Ca
coolant sensor ie. rough idle ??
I have herd that the coolant sensor, if not working properly, can mess up the idle. My 89 has and idle problem, I have changed the EGR valve, EGR switch, the 02 sensor, cap and rotor, distributor module, and still idle is rough, it jumps up and down at the stop signs. Once I am running, it appears to be fine...............although I think my fuel milage is too low......12-15 avg. Any suggestions........coolant sensor or not??
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: coolant sensor ie. rough idle ?? (89blkvet)
You can uses the ECM's diagnostic mode (described on my site, link in sig. below) to see if the ECM is going/staying in closed loop mode when warmed up.
If not, since you know the O2 sensor is good, replace the coolant temp sensor.
If so, put a timing light in turn onto each spark plug wire and see if engine misses coincide with missed flashes at any plug wire.
You might also clean the TB, it's bore and the IAC pintel with it's bore under the TB.
If not, since you know the O2 sensor is good, replace the coolant temp sensor.
If so, put a timing light in turn onto each spark plug wire and see if engine misses coincide with missed flashes at any plug wire.
You might also clean the TB, it's bore and the IAC pintel with it's bore under the TB.
Race Director
Joined: Jun 2000
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From: Oakland CA
St. Jude Donor '03
Re: coolant sensor ie. rough idle ?? (89blkvet)
I've never heard about this on a Corvette but I know that it's true for Volkswagens. My coolant temperature sensor was shot and the idle was really rough. I changed the sensor and everything was fine again. Do the 89's have two sensors like on my 94? I have one sensor on the passenger side of the block and one at the front of the waterpump.
Thread Starter
Intermediate
Joined: Oct 2003
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From: San Lorenzo Ca
Re: coolant sensor ie. rough idle ?? (El Guapo)
Thanks for the help, 65Z01 I am unable to locate the ECM diag. mode on your link. El Guapo, yes I do believe that my car has the coolant temp sensor. I have heard that this sometimes, if not working properly, can reek havoc on the idle…Tell ya the truth, I am not sure how that works.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: coolant sensor ie. rough idle ?? (89blkvet)
89blkvet sorry for the bad lead, that page link on my site is in the line "How to Use - L98 Field Service Mode"; click on the "L98 Field Service Mode" portion of the line.
The coolant temp sensor used by the ECM is located in the front of the block below the TB; the one in the right side of the block below #6 & #8 plugs is used by the display only.
The coolant temp sensor used by the ECM is located in the front of the block below the TB; the one in the right side of the block below #6 & #8 plugs is used by the display only.
Racer
Joined: Mar 2002
Posts: 345
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From: decatur il
Re: coolant sensor ie. rough idle ?? (89blkvet)
Last summer my 90 started to idle up and down from 500 to 800 rpm turned out to be fuel injectors. It ran ok during normal driving except for the shift to overdrive. Just a thought!!
