No Power to Fuel Pump

[J-P]

Here's the situation:

1973.5 911T

Turned the key, heard the fuel pump going, cranked for a couple of seconds. The engine didn't quite catch the first time, so I turned the key off, then back on to try a re-start, but no longer heard the sound of the fuel pump.

I checked all of the fuses, but they looked fine. Just for good measure I removed the old fuse, cleaned the contacts, and inserted a new fuze, but still no luck (This would be the #8 16a fuze from the top of the stack).

Next, I broke out the wiring diagram and saw that the turn signals, brake lights, and back-up lights are on the same circuit. When I checked if those were working, sure enough they were not.

I don't know what else to check at this point, and am not enthused about paying for a flatbed to the repair shop.

Just for background, I did have a problem with the right turn signal not working a couple of weeks back. It was supposedly repaired, but I noticed it would still "stick" occasionally when I used it.

I don't know if there's a short in the system that would have taken out the fuel pump, but based on the symptoms I've described here, there seems to be a likely connection. However, it did not show itself in the fuses and I don't think the turn signal relay would have this effect on the fuel pump if it happened to be bad.

Any thoughts/suggestions would be much appreciated. Thanks in advance.

[J-P]

Come on, guys! I thought with the wealth of info on this board someone would have the cure:-)

[37yrold911]

the cure is just work - check the voltage or use a trouble light and work your way back to where you have power

[caproader]

You might want to try running a test ground wire straight from the pump ground connection to a good ground on the body. I had the same problem once on a 73.5 Targa. When I ran an additional ground from the pump to the body, it ran fine.

John Meyer, aka the capitalist roader, proud member #322
73 T with 2.7 mfi, sportomatic 73 S, and 69 912 in parts

[teescott]

I had a similar problem with the fuel filter body not being grounded. It was keeping the cold start solenoid on top from working. When I ran a test ground to the body and earth the solenoid worked. It could be the same thing with the pump.
Scott

[ttweed]

Isn't there a relay that energizes the fuel pump circuit? If it is bad, you could be getting no power to it without blowing a fuse. I am no expert on the CIS systems, but there is a guy named Jim Williams on Rennlist who has put together a great resource for CIS on his website that may help you in your troubleshooting efforts.

Good luck,
TT

[J-P]

Hi guys,

Thanks for all of the advice. Much to my embarrassment, Tony at TLG was able to resolve this for me...OVER THE PHONE!!! I just had to go back and be more thorough with what I had done before.

Tony suggested I double check the wires and the screws in the fuse box housing, as they tend to get corroded with heat and amperage.

I loosened and retightened every screw in the fuse box. I paid particular attention to the #8 fuse controlling the fuel pump by taking a pair of needle nose and physically moving the wires back and forth after I had loosened the screw.

I did this in order to loosen any corrosion which may have formed on the wires.

Sure enough, a turn of the key provided the comforting humming sound of the fuel pump and she fired right up.

[Mr9146]

The secret is out ... MY DAD IS THE MAN!!

[J-P]

Hey Marco,

Your dad is the man. Tell him happy B-Day for me.

J-P

[Aircool]

J-P: Glad you are back in business. The same thing happened to my car with the previous owner. The shop wound up relocating the pump to the front of the car rather than properly diagnose. Some day I will make it right again. You may want to go over all of the fusebox connections with a good contact cleaner. Take care.