Fender_mender1

Hello my 928 is killing me last summer I replaced the fuel pump and it ran then afterwards I played with the rear hatch lock cause it wouldn't close since then it hasn't run the dash doesn't say the alarm is on but Im totally lost at this points there's no voltage at fuel pump and I just tested for spark and nothing I've done the timing chain and mass airflow sensor just a few hundred miles ago any help would be great like how do I jump the alarm box to make sure it isn't the alarm thank you

Mrmerlin

did you ever do a CE panel refresh?
this should be done before you attempt to drive the car

Fender_mender1

I have no idea what that is

Fender_mender1

Ok I read up on the panel refresh I'll try that I am puzzled tho the car was running and just stoped but it does make sense when I try to test fuses with my meter I only can a buzz on the far right banks maybe 8 fuses and nothing on the rest

Mrmerlin

you should also get the WSM

killav

I had this exact same symptom on my 85, and it was my EZF Ignition relay. It is relay XVI in this chart:

https://www.928gt.com/t-8586fuse.aspx

I replaced the EZF, LH, and fuel pump relays with new, and have not had a no start issue since.

bureau13

If your horn works, you can try the horn relay in each of those positions, to see if it helps.

Wisconsin Joe

First off, what year is your car? There are significant differences that would affect what you need to do.

No spark & no power to the fuel pump is very often bad relays. If your horn honks, use the horn relay in place of the fuel pump relay and the ignition box relay (or just get a few new ones) to see if that's a problem.

Second off, read the "New Visitor" sticky. There's a ton of info in there. Links to what you need (like a CE panel refresh). Here is one:

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

The search function on here isn't the greatest, but a simple "928 alarm bypass" into the search box came up with this about halfway down the page:

https://rennlist.com/forums/928-foru...ss-method.html

Good luck.

Fender_mender1

My car is a 1985.5

ROG100

Do you mean 86.5? No such animal as an 85.5 that I know of. Is it a 16v or 32v?

Maybe CPS.

Smokin' Joe

First, buy new relays for the fuel pump, EZF and LH to eliminate that series of problems. They're cheap and prone to going bad. Once you rule them out put one or two in the glovebox just in case you need one on the road. While you're changing out the relays jumper the fuel pump relay and see if it runs. Top tip: disconnect the battery before doing this. Once you hook up the jumper the pump will come on even with the key off. Hopefully that will fix the problem. Check the fuel pump fuse (42?) too.

If that doesn't work, get a wiring diagram from the WSM and break out the multimeter. I just went round and round chasing a problem like this. In my case the car would start when cold and run for a few minutes then die. It turned out to be a bad EZF but I'm glad I took the time to trouble shoot the entire system before I started throwing parts at it. Some of these parts ain't cheap.

Fender_mender1

My car is a 32v 85.5 I guess it's a half year model. Did they have the 32v in 85 ? I did the fuel pump relay and checked fuse hopefully tomorrow ill have time to check the other relays its on the lift at my shop very busy there's alway another damn car underneath it to jump fuel pump relay I jump between 30 and 87 correct?

Smokin' Joe

The USA 1985 & 1986 cars were all 32V 5.0L. There wasn't an 85.5 model. There was an 86.5 which had the body and engine of the 86 but the suspension and exhaust of the S4.

Avar928

Look at your brakes, does it say Porsche on it? If so, 86.5. If not, 85 or early 86. The 86.5s had the big Brembo brakes as well. I have an early '86 which is basically an '85 with standard ABS.

OTR18WHEELER

is this YOUR car?, or did your Dad hide the keys when he went out of town?.