I have a 1995 LT1 from a Caprice in a 3rd gen firebird. I had an issue with random stuttering from the engine awhile back and when I hooked up a laptop to watch the ODBII stream, I saw that the CTS kept dropping to -40F randomly and causing these stutters. I changed the CTS and it worked good for a couple of days, then developed the same issue. I changed it again and it lasted for a few weeks and then developed the same issue.

Has anyone heard of this happening before or do I have a unique problem? I'm considering just hooking a switch for HOT/COLD which will output the proper voltage/resistance based on the conditions... Or I guess it could be the ECU's problem of interpreting the signal.

Anyone suggest a good way to check for that? It's intermittent which makes it difficult. I suppose I could hook a voltmeter/ohm-meter in parallel with the sensor and watch that, but would the ECU's connection affect the readings?

 

You probably have a poor connection somewhere.

 

I thought of that too but it worked fine for months after the initial swap... Then I ran into these problems. I guess I could run my own loom directly from the appropriate pins on the ECU to test the theory.

Just thought I would put it out there in case it's something other people have seen before. Anyone else have any thoughts?

 

This thread is pretty old but just wanted to update it, The car sat for a number of months and I've been getting back into it lately, and had the same problem appear. It turned out to be a bad pigtail. I snipped the CTS connector and replaced it with one from another harness and viola it seems to be working well and consistantly now.

 

Thanks for the update. posting a update or final review really help for future reference

 

gotta love chasing down those electrical gremlins. makes everything all that more fun, but glad to see you were able to fix the problem.

 

Electrical gremlins are my favorite haha. The freescan utility was indispensable at helping me diagnose it... It was clear when I saw the engine temp kept dropping to -40f and then one second later jump back to 170 or wherever it was... It was a good learning experience too. Now I know firsthand what the symptoms of an erratic/bad connection to the CTS can cause and if I ever see similar symptoms again on a car, even one without an ODBII data stream that I can read, you can bet I will eye up the CTS connector and sensor!

 

How did you reattach the new pigtail?