electrical problems on 911SC

Volkovich · 11-03-2003, 08:00 AM

I have an intermitment electrical problem that is going to live me stranded somewhere soon.

Every so often when I turn on the key the green and red dashboard lights will NOT turn and my car won't fire up. The starter will turn over and all the other electric systems seem to work (lights, radio, etc.) but I don't seem to be getting any gas.

I don't see any blown fuses and I replaced the fuel pump relay but that didn't help.

If I wiggle the mess of wires that goes to the stereo I have been able to get the dashboard to light up and the car will fire up as well.

I figure I have a short somewhere and was wondering which circuit I should start picking through first. Does it make sense that the dashboard lights and fuel pump don't work at the same time?

Thanks in advance.
Tim

Jdub · 11-03-2003, 08:11 AM

It may simply be the ignition, but....

You will need to make order in the disorder that is the wiring under the dash. I'd take a guess at a split/break in a wire that is rubbing on hard sheetmetal, but then again if you have an aftermarket stereo/alarm who knows what is going on under there.

Best bet is to get a visual: pull the negative cable from the battery. Next, get two huge pillows to lie on, on your back, and prepare to carefully pick through the wiring harness under the dash. Organize wires loosely into correctly-oriented subharnesses and tie them together with string (do not use zip ties yet). Look closely for any breaks or loose connections, esp. anything that might look corroded (doubtful in the interior cabin, under-dash, but?).

Now put the neg. terminal back on, carefully be sure you have no grounded wires (smell any smoke? Hear anything sizzling?) and have a second person let you know when the dash lights go flaky as you manipulate wires. Try to trace the action of the wire movement to the lights. When, hopefully, you have found something, correct the break or connection.

John

GB83SC · 11-03-2003, 08:33 AM

Take the fuel pump fuse out, clean the contacts and see if that helps. Count six fuses from the windshield forward.
Its #16 on the fuse board.
Good luck.

Doug Zielke · 11-03-2003, 08:39 AM

All of the above, but use your multimeter, and start checking things methodically.

RoninLB · 11-03-2003, 08:46 AM

all of the above +

an old ignition switch can make searching for a mystery electric problem a PIA.. I figure that 100k miles on a switch is one foot is on a banana peel and the other foot is in the grave/ whatever.......Ron

Early_S_Man · 03:29 PM

Tim,

It doesn't sound like a fuse-related problem to me!!!

If it was only related to the fuel pump power supply, I don't think you would be having issues with dash lights ...

It sounds like the electrical portion of the ignition switch needs to be replaced ... but there are a couple of tersts that need to be done, FIRST. Test #1 would point to problems other than the ignition switch! Problems detected in test #2 could be related to the ignition switch, but other problems with fuel pump relay or sensor plate switch could also cause intermittent problems starting!

1. Check to see if +12 Volts is available at terminal #30 of the fuel pump relay, ands at the fuel pump -- while thw starter is cranking. It could be a problem with the fuel pump relay rather than the ignition switch -- if you aren't getting power to the pump[ during the cranking cycle.

2. With the ignition switch on -- check to see if raising the air flow sensor plate causes the fuel pump to turn on.

The diagram below may assist in troubleshooting either of the above problem areas:

Volkovich · 11-04-2003, 03:48 AM

Wow, thanks for all the replys. I'll let you know what I find out.