KY944

Clean the fuel pump fuse contacts!!! Was at work, gettting ready to pull the car in to put in the new Royal Purple transmission fluid...bam crank no start! The car had been hard starting/excessive cranking for awhile and was attributing it to ignition...wrong was I. Had a spare fuel pump relay...no change. Decided to jumper wire in place of relay and the #22 fuse arched. It took a nice gun cleaning brush and a new buss fuse to correct the problem and wow...what a difference. The car has never ran that good. So now added to my list is to clean ALL fuses and relay connections. Note the car is mechanical injected...would run ok on less voltage to pump...Rob

928drvr86.5

I don't know about 50HP, but yeah the fuel pump circuit has caused many people problems on these cars.

Ispeed

Dave C. has recomended doing all new relays and fuses just to eliminate another potential source of loss and dead battery episodes.
Big thumbs up from me.

Chuck Schreiber

Would the car run better after turning it off and on? Going through this right now on my 79!
Runs better after the turn off/on fix then slowly gets worse. Turn off/on gets better then......
You get the picture.

KY944

No Chuck, it was evidently a gradual build up of corrosion/resistance. I had noticed hard starts but ran "fine" while driving. On my 83 euro (CIS injected as yours) it is fuse #22. easy to check and also pull the relayand tighten the terminal ends. Also found a couple of days later it did the same thing to me. The terminal that holds the buss fuse in at the top of the fuse holder needed to be recrimped...hope it helps. Rob

Chuck Schreiber

Thanks,

I plan on getting into the Relay/fuse panel in the next week or so.

Simon Jester

After having all kinds of trouble with the instruments, lights...etc, etc, I removed the fuse panel. It was all tarnished and the crimps were loose in places. I removed all the springy-thingy fuse holders and cleaned the contacts up as well as flowing solder into the connectors that were really loose. I put spade connectors back instead of the Euro fuse things. (A little bending with needlenose and a quick solder joint.) This allowed me to install modern minifuse holders and minifuses. It's bulkier, but the contacts are perfect. I fluxed the remaining connector sockets to clean the tarnish and reinstalled the relays.

I reflowed the solder on the fuel level sensor and the 14(?) pin connector on the right front of the engine bay.

Everything works perfect now. I can go back to pitying drivers without a 928.

KY944

I wondered if the newer style fuse connectors could be installed- appeared as if it would...sounds like you did what the factory should have onsuch a high end electrically laden car...Kudos!!! Rob

Chuck Schreiber

Just pulled the relay panel the other day. Haven't gotten into it yet, but Dave "Sharkskin" has a fantastic write up here

http://members.rennlist.com/sharkski...04-Bzzzzzt.htm

Nice job Dave!

I'd like to scrap the crappy Euro fuses and go with something different.
Simon, when you say mini fuses are you talking about the push in style??
I've also heard others using the glass "buss" fuses. At a minimum I'll do everything that Dave mentions in his write up along with replacing ALL fuses and some of the relays.

Any feedback appreciated!!

Emickelsen

Hey Simon, you pulled the fuse panel all the out of the car? Is that just a matter of undoing the two bolts and the 7 or 8 wire plugs? This is great stuff. It's almost like you guys have been driving my car. I'm getting on this right away.

John Krawczyk

This will be my weekend project. Cleaning the fuse panel up and removing the pod/instrument cluster. I'm hoping this will cure my tack and passenger window woes. Though i suspect a gunked up bad switch for the window not working.

Chuck Schreiber

John,

My window switches were really bad on the 79 a while back. When I took them apart, they were gummed up with grease, dirt, etc. They were sticking and the graphics were rubbed off as well. I bought 2 new ones as I figured replacing them once every 25 years or so is not that bad. They work fantastic. More of a click then a clunk when engaging. About $35 per switch.

tilac999

My fuel pump fuse (blade style) melted and the car wouldn't start. Luckily it happened in my driveway. dirty connection, white and powdery, must have caused resistance and thus heat to build up. After a good cleaning and fuse replacement, I'm amazed at how much stronger it pulls. 'Feels like 50 hp' might be a stretch but man I feel a BIG difference.

dprantl

Wow that is not good at all. If significant power was gained by replacing the fuel pump fuse, that means the car was running pretty lean. A new reason to have a wbO2 and gauge in a car?

Dan
'91 928GT S/C 475hp/460lb.ft

tilac999

Ya, it felt a bit lean at part-throttle cruise but not overly so. Mostly on-off throttle while shifting is very much improved. WOT was fine. My ROW car has no provision for an 02 sensor.