Symptoms of bad coolant temp. sensor?..
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Joined: May 2006
Posts: 437
Symptoms of bad coolant temp. sensor?..
Hey guys,
Here is the situation: My car has recently gotten a new opti, wires, coil, etc. But now, when starting the car, it will idle fine up until a certain point.
THEN: all the sudden it will kick the service engine light on, and start idling real crappy at the same time (wavering from 600-1000 RPM's on its own), and the fans will turn on at that exact same time also (even though the temp. gauge is only reading around 175 degrees). Then it will usually continue like that for a while - and sometimes go back to idling good again and the engine light will turn off - but only for a little while before it goes into the bad mode again. It is like someone is turning a switch on and off every couple minutes or so!!
BUT - EVERY time, if I shut the car off while running crappy, then start it up again right away, then it will run good for the first little while after re-starting. But not long after it will kick into the poor mode again.
Seems to me that this has something to do with a temperature issue. Especially because the fans come on exactly as it starts screwing up and kicks the light on. My car is a 1997 - but I have the OBD1 conversion computer from PCMforless - plus a 160 degree thermostat. Could my issue be that the thermostat is not heating the car up enough for the computer to be happy? Or has my coolant temp. sensor gone bad? Or is it something else all together?...
Thanx in advance for the help
Here is the situation: My car has recently gotten a new opti, wires, coil, etc. But now, when starting the car, it will idle fine up until a certain point.
THEN: all the sudden it will kick the service engine light on, and start idling real crappy at the same time (wavering from 600-1000 RPM's on its own), and the fans will turn on at that exact same time also (even though the temp. gauge is only reading around 175 degrees). Then it will usually continue like that for a while - and sometimes go back to idling good again and the engine light will turn off - but only for a little while before it goes into the bad mode again. It is like someone is turning a switch on and off every couple minutes or so!!
BUT - EVERY time, if I shut the car off while running crappy, then start it up again right away, then it will run good for the first little while after re-starting. But not long after it will kick into the poor mode again.
Seems to me that this has something to do with a temperature issue. Especially because the fans come on exactly as it starts screwing up and kicks the light on. My car is a 1997 - but I have the OBD1 conversion computer from PCMforless - plus a 160 degree thermostat. Could my issue be that the thermostat is not heating the car up enough for the computer to be happy? Or has my coolant temp. sensor gone bad? Or is it something else all together?...
Thanx in advance for the help
Registered User
Joined: Apr 2004
Posts: 236
From: Charlotte, NC
Anytime the SES light is on the fans will constantly run. Sounds like it's missing to me. I'd check plug wires and other new connections to make sure they're good. If it's not a wire loose or something you need to scan it to find out what it's seeing.
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Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
Sounds like it runs OK for the first 2 or 3 minutes after startup, when its in open loop, then goes downhill when it kicks into closed loop - that sound accurate?
But get it scanned. No sense guessing and spending money on parts.
But get it scanned. No sense guessing and spending money on parts.
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