I've been having semi-rare-but-random hot-start issues, and then the car went into limp-home mode. I had been putting off replacing the MAF connector but that seemed like the likely problem (for the limp mode, at least) so I finally did that. And it seemed to fix it, but the car was still running quite poorly. I hooked up the breakout box to the LH to see if I could figure out anything, fully expecting that I had a bad connection in my repaired MAF harness. However, I tested the Temp II sensor at the LH, and while it was reading in the ballpark with the ignition on but the car not running, as soon as I would start the car it read as an open circuit. Shut the car off, pretty much immediately returned to a number that was about right. I repeated this test several times. That seems weird to me. One of my other cars had a problem where the alternator wouldn't charge the car, whenever I'd measure voltage at various points without a load it was correct, but even the load of the alternator light in the dash knocked it down to nothing. The culprit was a braided ground strap that appeared intact but had essentially rotted away to nothing internally. That makes sense because the few good strands hanging in there weren't enough to supply real current. In this case, it's just measuring the resistance. Why would that change because the car is running? Maybe there's some other reason for this phenomenon?

In any case, I took a look at the boot and wiring at the sensor, and...it's not good. So I'm going to need to fix that. Someone suggested I should really remove the harness and repair everything off the car. That's probably the right idea, but at my speed I'll be back on the road by 2028. So for now I will do the ones I can see.

This obviously needs to get done regardless, but if there's another "normal" reason measuring the temp II resistance won't work, please let me know.

 

Are you saying that you’re trying to continue to measure the sensor resistance with the car running? If so it won’t work because the LH is applying a voltage to it so it can measure the resistance, your meter is flipping out as a result.

 

NOTE its a good practice to replace the temp 2 sensor along with the temp 2 connector,
as the wires are usually damaged under the boot .

If your holding off replacing the connector for the temp 2,
then dont hold back any further.
Also make sure the WB is not powder coated, as this can corrupt the ground path for the sensor.

 

Ugh. Of course you are right. Those courses were too long ago. So maybe I'm way off base here.

 

Yeah, the wires inside the compromised boot don't look very good. I replaced the sensor a couple years back, so I was assuming it was unlikely to be bad. No powder coating issues, I made sure all of that was good when I did my intake refresh a few years ago.

I'm thinking I may not have found the smoking gun I was hoping for, given my brain fart above.

 

shorted wires inside the boot happen frequently at this location,
since it sits in a turbulent hot location.