electrical problem

[ChevyGuy1022]

3.4 might remember me complaining about a vacuum leak that everyone told me was a load sensor problem. After a long list of repairs we can rule that out. My issue now is (i think) the voltage regulator. My voltmeter keeps freakin out and dancin all over the place (mostly towards the lower numbers) and my lights dim and all that jazz. The only reason I want this fixed soon is because it's obnoxious when the car stalls in traffic. So heres the list of repairs to rule out any suggestions that have already been tended to.

Throttle position sensor replaced
Idle air control valve replaced
MAP sensor replaced
Transmission adjusted
Torque Converter replaced
Fuel Injection system cleaned
Intake manifold cleaned
EGR valve replaced
EGR recirculation tube gaskets replaced
Left Intake plenum gasket replaced
Right intake plenum gasket replaced
Upper intake manifold gasket replaced
Lower intake manifold gasket replaced
Throttle body gasket replaced
Fuel pump replaced
Superceding PROM chip installed


So. In this situation... What would YOU do?

[3.4 [deployed]]

drive car to place that can check your charginf system, like Auto Zone, Advance Auto, etc. They can test your batt, alt, & starter & see if anything is dying/killing your car. preferably @ night & using the brake pedal as little as possible.

edit: fuel filter replaced w/fuel pump, right? just checking

[ August 28, 2004, 08:12 PM: Message edited by: 3.4 [deployed] ]

[Jerriko]

Sounds like a bad ground to me. Bad grounds do all sorts of weird things to cars. Still, get the charging system checked. It sounds like its an intermediate problem so the charging system check may not show any results. Has this car been threw any of the following:
-engine overhaul or engine removal
-flood or heavy rain
-electrical fire
-does it go through any fuses
-battery location changed
-throw any codes
But one thing you can check out is the positive battery wires from the battery to starter (and alternator). I had a Monte Carlo that would die for no reason. When it died, you could not even jump it. Turns out the main positive cable had worn through the insulation and was grounding on the chassis of the car.

[ChevyGuy1022]

Originally posted by Jerriko:
Sounds like a bad ground to me. Bad grounds do all sorts of weird things to cars. Still, get the charging system checked. It sounds like its an intermediate problem so the charging system check may not show any results. Has this car been threw any of the following:
-engine overhaul or engine removal
-flood or heavy rain
-electrical fire
-does it go through any fuses
-battery location changed
-throw any codes
But one thing you can check out is the positive battery wires from the battery to starter (and alternator). I had a Monte Carlo that would die for no reason. When it died, you could not even jump it. Turns out the main positive cable had worn through the insulation and was grounding on the chassis of the car.

I live in Florida, so yeah heavy rain I would say so. It DOES go through 20 amp fuses on circuit 11 I believe, and i think it's due to a bad ground in the cigarette lighter (plug in phone charger/radar detector and dome light, stereo, cig lighter application turns off).
And no it doesn't throw out any trouble codes.

[Jerriko]

I would definitely be concerned about that fuse it keeps blowing. The cigarette lighter circuit is a circuit that is ALWAYS on. The could easily cause problems for the charging system (through the battery). Do you use the radar detector and the phone charger at the same time? Do you use one of those 'Y' adapters for the cigarette lighter? They are a really bad idea. The circuit was designed to handle 20 amps. If you use the radar detector and phone charger, that may draw more than 20 amps. Of course the fuse will blow but after repeated electrical spikes, the high current WILL damage other components of the circuit. Bad grounds don't blow fuses. Bad grounds disrupt correct electrical flow. Since you live in FL, I would disconnect the major grounds and clean them.

[ChevyGuy1022]

I don't use a Y connector and I only run one at a time (none recently for fear of blowing another fuse - It blows the 20 amp fuse when I plug something in).

Anyway. I took it back to the mechanic I've been taking it to every other day or so, and he was watching the readout on his Snap-On Scanner. The TPS was reading .56V with the keyon and engine off. Turn the engine over and it jumps to .6V and 1% throttle. Tap the gas and sometimes it'll stay somewhere in the vicinity of .65V and 2% throttle, and sometimes it'll go back down to .6 and idle. Now, the part on the car is a Wells TPS. Today I'm heading over after classes to have him put in an AC Delco TPS, which he says will probably fix my problem.

Apparently GM cars with anything other than AC Delco electrical parts present problems otherwise not encountered. Same with Ford vehicles, but who cares about Fords, right?

So, I'll update later on what happens with the TPS. Maybe someone with the same problem as me can benefit from reading all of this.

[Jerriko]

Why are you changing the TPS? Those readings are correct. The voltage readings should vary between .5V and 5.0 volts. The voltage will increase as the throttle plate opens. If you open the throttle plate by a percent or two, you should not expect to see the voltage rise anymore than it did with you. Sounds like you are throwing money away to me. And even if the voltage doesn't increase as you like, the TPS sensor is ADJUSTABLE! If the sensor is installed correctly, you will get problems with it. The only reason you would have to replace the TPS is if you got no voltage reading out of it. And what does that have to do with your voltage of the charging system.
And know since you have mentioned that you blow the fuse anytime you plug something into the cigarette lighter, the problem is obviously there. Look for a melted hot wire to the cigarette lighter.

[ChevyGuy1022]

Originally posted by Jerriko:
Why are you changing the TPS? Those readings are correct. The voltage readings should vary between .5V and 5.0 volts. The voltage will increase as the throttle plate opens. If you open the throttle plate by a percent or two, you should not expect to see the voltage rise anymore than it did with you. Sounds like you are throwing money away to me. And even if the voltage doesn't increase as you like, the TPS sensor is ADJUSTABLE! If the sensor is installed correctly, you will get problems with it. The only reason you would have to replace the TPS is if you got no voltage reading out of it. And what does that have to do with your voltage of the charging system.
And know since you have mentioned that you blow the fuse anytime you plug something into the cigarette lighter, the problem is obviously there. Look for a melted hot wire to the cigarette lighter.

All in all, thats great. Anyway, we put the original TPS on... the one I kept from when I changed it myself. Works better than before. Problem still persists. Although it didnt solve the problem, it did change the throttle response on both the scanner and feel of driving.

[ChevyGuy1022]

Ok, so now Im overly confused. After the original TPS was put back n the car and the computer reset, it was still doing the same thing. The past two or three days it hasn't done it. Can the computer store new values for something that drastically changes the idle quality? It sits at 750-800 w/o AC and hasn't stalled since sunday evening (the fifth of september). Thoughts?

[3.4 slow to go]

Thoughts: You fixed it.

But anyway,......have you checked the wiring going to the cig lighter jack? It also goes to the console light, and IIRC some dash lights too. When Mogobs & myself were working on sacs 68 Camaro, we took the icm off, stared at it, put it back on & it magically fixed itself. go figure. sometimes shiz like that just happens.