So ran into some interesting issues today...
About 2 weeks ago my temp gauge sensor went. I parked the car until I could fix it. No other issues at the time. Checked the sensor (driver side block, below TB, Sensor had seen better days and rubber/plastic grommet inside the brass had degraded.
Ordered replacement, went and installed this morning. No big deal. Turn the key, Gauge dropped from the top end and back down to the cold end.
Buttoned everything up inside the engine bay. Went to start the car. Terrible idle. stays running, but has a "hiccup" which can be heard from the pod filter. Hiccup is followed by a burple in the exhaust (sounds like a misfire).
I'm thinking this was just the car sorting out the IAC because the battery was disconnected and let it run. But the issue continued even after the idle has settled.
Shut the car off, started it up, brought it back in the garage.
Did the general checks, all the stuff I touched. Listened to fuel pump, all good. Listened to motor, sounded fine. Just the burple during the "hiccup".
"Hiccup" got a bit worse. Shut the car off, and restarted again. Now it won't run. I suspected the IAC. Jumpy Tach while attempting to run.
Disconnected the IAC, Got the engine to run without the IAC, stayed running without the "hiccup".
Went home, I had a spare IAC which was replaced on another car, and I had a spare gasket with that IAC. Really went to get the gasket, local stores had none in stock...
Pull the IAC and cleaned it. It was a little dirty, but I've seen worse. Re-assembled with cleaned IAC. Started the car, no tach. Engine won't run.
I don't have my sensor scanner, so start looking over my work again, assuming I've missed a hose, took off a ground, etc. No dice.
I've started looking over the harness. I've noticed a few cracks. One bad, exposed portion of wire, everything else minor. I did some quick patches with liquid electrical tape. Car still does not run. Tach comes back.
Pulled the wire connect off the new temp gauge sensor, which is what I was repairing. No change. Gauge didn't work again, but the car still would not run. Put the temp gauge wire back on.
Went home, got my sensor reader. Went back to the garage. Reader shows the IAT to be -40F. So assuming bad IAT, and maybe that is causing all the bad idle issues.
Went home, got a spare IAT sensor from a non-SVT. More or less the same sensor. Went back to garage. Same issue, no read on the sensor.
I took more loom apart. I don't see any further issues. Wiring inside the plastic loom is fine for bot the IAT and the MAF going into the larger portion of the harness.
Begin to check the other half harness, passenger side, never rear valve cover.. Not much else to touch there, just added spots of liquid electrical tape. I had not touched this area previously, but I know the engine temp runs through that portion of the harness. Assuming the IAT does as well (wire color matches).
Being adventurous, and not going home again for a voltmeter, I put a jumper in the IAT connector. Sensor Reader shows 302F. So the cracked wiring is sender/receiving some sort of signal, or at least can read the analogue. Not sure of the signal type.
Put it all back together another. Had to charge the battery a few times today from all the starting/powered-not-running testing. Car is still a hot mess, but I'm out of ideas. Anyone have suggestions? Am I at the point of pulling the entire engine loom? Only thought I had was the rear harness incurred new cracks when I pulled the IAC. But after 11 hours in the garage, I'm done for the day. Any help would be appreciated!
About 2 weeks ago my temp gauge sensor went. I parked the car until I could fix it. No other issues at the time. Checked the sensor (driver side block, below TB, Sensor had seen better days and rubber/plastic grommet inside the brass had degraded.
Ordered replacement, went and installed this morning. No big deal. Turn the key, Gauge dropped from the top end and back down to the cold end.
Buttoned everything up inside the engine bay. Went to start the car. Terrible idle. stays running, but has a "hiccup" which can be heard from the pod filter. Hiccup is followed by a burple in the exhaust (sounds like a misfire).
I'm thinking this was just the car sorting out the IAC because the battery was disconnected and let it run. But the issue continued even after the idle has settled.
Shut the car off, started it up, brought it back in the garage.
Did the general checks, all the stuff I touched. Listened to fuel pump, all good. Listened to motor, sounded fine. Just the burple during the "hiccup".
"Hiccup" got a bit worse. Shut the car off, and restarted again. Now it won't run. I suspected the IAC. Jumpy Tach while attempting to run.
Disconnected the IAC, Got the engine to run without the IAC, stayed running without the "hiccup".
Went home, I had a spare IAC which was replaced on another car, and I had a spare gasket with that IAC. Really went to get the gasket, local stores had none in stock...
Pull the IAC and cleaned it. It was a little dirty, but I've seen worse. Re-assembled with cleaned IAC. Started the car, no tach. Engine won't run.
I don't have my sensor scanner, so start looking over my work again, assuming I've missed a hose, took off a ground, etc. No dice.
I've started looking over the harness. I've noticed a few cracks. One bad, exposed portion of wire, everything else minor. I did some quick patches with liquid electrical tape. Car still does not run. Tach comes back.
Pulled the wire connect off the new temp gauge sensor, which is what I was repairing. No change. Gauge didn't work again, but the car still would not run. Put the temp gauge wire back on.
Went home, got my sensor reader. Went back to the garage. Reader shows the IAT to be -40F. So assuming bad IAT, and maybe that is causing all the bad idle issues.
Went home, got a spare IAT sensor from a non-SVT. More or less the same sensor. Went back to garage. Same issue, no read on the sensor.
I took more loom apart. I don't see any further issues. Wiring inside the plastic loom is fine for bot the IAT and the MAF going into the larger portion of the harness.
Begin to check the other half harness, passenger side, never rear valve cover.. Not much else to touch there, just added spots of liquid electrical tape. I had not touched this area previously, but I know the engine temp runs through that portion of the harness. Assuming the IAT does as well (wire color matches).
Being adventurous, and not going home again for a voltmeter, I put a jumper in the IAT connector. Sensor Reader shows 302F. So the cracked wiring is sender/receiving some sort of signal, or at least can read the analogue. Not sure of the signal type.
Put it all back together another. Had to charge the battery a few times today from all the starting/powered-not-running testing. Car is still a hot mess, but I'm out of ideas. Anyone have suggestions? Am I at the point of pulling the entire engine loom? Only thought I had was the rear harness incurred new cracks when I pulled the IAC. But after 11 hours in the garage, I'm done for the day. Any help would be appreciated!