98 GTP SC HELP BNAYLOR! Compound Problem, Temp Gauge, More

[ktmccrary]

I inherited a 1998 GTP 3800 Supercharged car with a host of problems. I've fixed most of them, but I have started replacing items that aren't fixing problems.
The temp gauge self-tests from 0 to max to 0 when I turn on the key, but the gauge never moves off 0 when the engine is running. I have an Actron scanner showing it running at normal temp. This model has a 3-pin (dual output sensor) which I replaced. At first I couldn't even get a reading on the scanner with the new sensor, but traced that to a bad connection in the connector. Now it's back where it was at 0 again.

I have multiple problems and believe they may all be related.

I was getting a p0102 MAF sensor error but traced it to fuse 21 in the underhood fuse panel. Replaced it, blew it and replaced it again. It seems to blow if I rev it above 3000 rpm, and then of course the rev limiter won't allow it to rev about 4000 RPM.

The transmission indicator on the instrument cluster only lights up park when it is in park or when it is in 3rd (stil lights up in park) , All other gears have no indicator light, nor are there any lights on the floor console indicating the gear it is in.

The oil level light comes on whenever the shifter is taken out of park, while the ign sw is on with the engine running or not. I replaced the oil level switch, cleaned the connector, to no avail.

Thus far I replaced the oil level switch, the temperature sensor, and even the instrument cluster, and have solved nothing.

I'm down to either having mouse-chewed wiring somewhere or possibly the PCM is bad. I at least avoided buying a $130 MAF sensor when I found the blown fuse, but I haven't found the cause of the blown fuse yet. Any and all help will be greatly appreciated.

[grandprixgtx00]

I would venture to say you may have a bad ignition harness. However this is truly just a guess. We'll wait for a few other opinions

[olopezm]

I'm not an expert but I agree with grandprixgtx00 but could this also be a bad ground problem? Have you checked them?

Best regards,

Oscar.

[BNaylor]

Ignition switch/harness assembly is possible but I'd troubleshoot further to be sure.

Any other abnormal indications like headlights flickering, no cruise control, no fog lights, abs light on, HVAC issues, no turn signals, engine cutting off when using turn signals?

[tblake]

I didn't know the guages self test on any 97-03 GP's. I thought that was just an 04+ thing. At least I know my temp guage wont start at 0, self test to max, and return to 0 when I start my car.

[BNaylor]

Originally Posted by tblake

I thought that was just an 04+ thing.

Yup actual IP gauge self-test is an '04 and up (final generation) thang.

I think what he meant is at ignition ON the gauge should at least go to what the ECT has for engine coolant temperature. In his case its dead or abnormal.

[ktmccrary]

Sorry, slow to get back. Had to rebuild a freakin Saturn Engine. I actually did mean "self-test". When you turn the switch to the on position the temp gauge needle moves to max, then back to min where it remains even when the engine reaches operating temperature.
I have found some corrsion on both a pos and neg battery wire where it looks like it got into a pulley once upon a time. I need to investigate this further before pursuing other matters. I'll try to get back to you with results. Thanks. BTW this is a HUD model.

[tblake]

pretty sure its not supposed to self test. i'd have to say you have a circuit problem causing it to max out when you turn the ignition on.

[grandprixgtx00]

Originally Posted by tblake

pretty sure its not supposed to self test.