Last930

This weekend my 930 wouldn't start. It spins over fine, but doesn't get any fuel. I checked the fuse, the wires leading to it were a little corroded with signs of burned insulation where they met the fuse box. I cut off both ends, cleaned up the fuse connections and put in a new fuse, and it started and ran fine - the fuel pump noise was good and strong prior to turning the engine over. When I went to drive it last night - same thing - no fuel pump noise. There is power past the fuse. I swapped relays with a spare - no dice.
Any ideas how to troubleshoot this?
Thanks, Dave

PorschePhD

Dave,
Check the white wire going to the overboost switch. Make sure it is grounding on the switch. If not it will kill the fuel pump. Also check the relay in the rear for the overboost switch. Any and all will kill the pumps.

Exoticbro

I had a similar problem with mine last year.
Mine was intermitent would die when I went on boost.
thought it was the overboost switch, which was new.
Turned out to be the relay for the overboost sw.
Always carry a spare!!

Last930

I spent some time troubleshooting tonight- cleaned all contacts, verified the overboost ground, it seems that the problem is in the fuseholder itself. It looks as if the contacts ( the 2 parts that actually hold the fuse) corroded , and now there is intermittant contact between the holders and the part where the bottom wire is held in place with a screw. With all contacts clean and tight the fuel pumps are still intermittant, they come on and off when i wiggle the bottom part . Is there a way to replace just the #6 fuseholder? It looks as if the fuse board itself would need to come off the fender, but I can't tell if the individual fuseholder comes out, or if the entire board needs to be replaced. I appreciate any help or ideas! Dave

garrickl

Take a look at Lee Rice's tech article posted at the Pelican Parts BBS. Electrical Upgrades ..... it deals with the fuel pumps and hot relays. I did this upgrade and my fuel pump problems went away and all the electrics worked better ... my door locks now actually "pop" when activated.

http://www.pelicanparts.com/techarti...amblings-2.htm

rickc

I had a fit of a time with intermittent power failures until I disconnected and cleaned the main grounding terminals behind the fuel accumulator. It's amazing how a little corrosion on the brass rings will totally shut down your engine after it warms up. Check power to your cd box.
Rick
'78 930

Last930

Thanks for the help everybody, I appreciate it. The Rice article seems to be a good solution to the problem, but where do you mount the additional fuse holder? There's no room under the plastic cover to add anything. In the interim, I have bypassed the the bad fuseholder and wired in an individual inline 25 amp fuse( same rating) for the fuel pumps. It's not how I like to do things, but gets the car on the road again - at least until the snow flies!!