Thread: cooling sensor help!!!!!
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01-03-2011 07:47 PM #1
cooling sensor help!!!!!
I have an 84 (tbi) and runs super great BUT after cleaniing and painting my engine .....
I found that the cooling sensor--for the ecm in the front of the intake (2 wires)
BOTH of the wires are twisted together AND I GUESS its been like that for years with NO problem. I owned the car for 2 years without notice!
What is going on?
Why are the wires twisted together?
What happens when You twist those 2 wires together?
thanks alot
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01-04-2011 04:27 AM #2
If you never took notice and everything is working fine, then don't worry about the wires being twisted or not............live by the old adage........"if it ain't broke, don't fix it"
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01-04-2011 04:56 AM #3
i wonder if it mite be causing you to run in " cold " loop all the time .. but as sunset said .. dont worry .... be happy ..iv`e used up all my sick days at work .. can i call in dead ?
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01-04-2011 05:23 AM #4
40chevy,
Are you saying the two wires are twisted together without insulation, meaning they are shorted out, or that the two insulated wires are twisted together along their length, but still making the circuit? Just want to be sure what you are seeing and asking about.Roger
Enjoy the little things in life, and you may look back one day and realize that they were really the BIG things.
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01-04-2011 07:10 AM #5
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01-04-2011 07:53 AM #6
Easy fix. Napa ts4015 sensor and tsc200sb pigtail.
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01-04-2011 09:55 AM #7
When the engine is started cold, the ECM mode is open loop. This uses preset parameters to set injector pulse width, idle air, and ignition advance. The engine will run fine, but uses more fuel, and it will not make max horsepower.
Once the engine warms up, it goes into closed loop. At that point, it takes input from the various sensors, TPS, MAF, O2, temp sensor, oil pressure, knock sensor, ect., and uses that to calculate injector pulse width, Idle air, and ignition advance. This is closed loop. It will make more horsepower, and increase the fuel mileage.
The sensors for the most part operate on resistance. The computer supplies the sensor with a set voltage, and samples the return voltage, and uses the difference to make the calculations. If the return voltage is the same as supplied voltage, it reads that as a malfunction, and holds it in open loop.
When the early installers started retrofitting EFI engines, many of them just wired them for open loop to make them work with stock PROMs in non stock applications. One way to do this was to remove the temp sensor, and twist the wires together. It wasn't right, but it worked.
If you are happy with the way it runs, just leave it. But if you want all that you can get you will probably have to rework the harness for the right pin outs, and replace the PROM, or go to an aftermarket harness.Anyone can restore an old car, it takes a man to cut one up
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01-04-2011 11:10 AM #8
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01-04-2011 01:09 PM #9
i think we are both backwards .. the first paragraph of post # 8 says during cold start the ECM mode is open loop .. meaning current is not flowing .. causing cold run situation .. close the loop ( tie the wires together ) and it runs in warmed up mode .. that sound logical .. i quit being a mechanic when cars went computor but im still a hotrodderiv`e used up all my sick days at work .. can i call in dead ?
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01-04-2011 01:20 PM #10
Hey would there be a code pop up for this condition? I have a 98 Z71( new motor ) that I can barely in the hot of summer get up to 160 degrees. Right now in the winter 150. It runs smooth but does no have the power I would expect from a 5.7. Sorry to barge in but the conditions are similar.
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01-04-2011 03:33 PM #11
thanks, i've been looking for the anwser for this for awhile.
I knew the hotrodders would know the anwser!
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01-04-2011 04:18 PM #12
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01-04-2011 04:34 PM #13
40Chevy,
It sounds to me like enjenjo knows the specifics here, and he warns that if you want to wire in your coolant sensor you will probably need to rework your harness for the right pin outs, replace the PROM or go to an aftermarket harness. Someone probably took the easy open loop mode in the past, and now you either leave it alone, or dive in and do it right.Roger
Enjoy the little things in life, and you may look back one day and realize that they were really the BIG things.
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01-04-2011 05:44 PM #14
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01-04-2011 06:41 PM #15
Ok gang. It's been awhile. With everything that was going on taking care of my mom's affairs and making a few needed mods to the Healey, it was June before anything really got rolling on this...
My Little Red Muscle Truck