New 928 Owner Checking In

Hello All,

Just picked up a 1983 928S in stick last weekend. New to the 928, but not new to Porsche. The car is certainly a project, but in very good shape overall.

Currently cranking, but no start. I should be digging into it this weekend to see whats going on. The car has just over 130k on the odo, and was running up until 4-5 years ago. I'm thinking its a fuel delivery issue, but I'll be approaching this systematically to eliminate variables. I did notice there was at least 1 broken vac line. Not sure where it leads, but I have all the 928 Factory Service Manuals on PDF, so I should be able to sort it out.

I'll be looking to replace all the fuel lines, vac lines and any other wear components, with the goal of achieving reliability from this car, not as a DD, but as something I can drive cross country without concern.

Should be a fun project, and it'll certainly be taking me away from my other project cars until I get it sorted. I've always liked the 928 and I'm glad to be able to add one to the fleet.

Went over the car thuroughly, and replaced a few vac lines on the front passenger side of the engine. All were very brittle, and broke on contact. Fortunately the plastic tee did not crumble.

Was able to determine the no fuel issue is due to an inoperable sensor not triggering the fuel pump relay. With the fuel pump telay jumpered, I have power at tbe pump, and I can start and rev the engine. Will not idle yet, but its on its way!

Nice collection! It sounds like you and I may have the same issue. My car is an 88, but after a 150 mile journey a week ago, I parked the car safely at home. The fuel pump is no more. It is a new pump, so I am hoping the pump is ok. So far in the best test I could do on my own in five minutes, it appears there is no power making it to the fuel pump. I haven't swapped my relay yet. Have you figured out what sensor is your issue yet?

I found that my flywheel position sensor (reference mark sensor per the FSM) is missing entirely. I pulled one off a 944 parts car, but I couldn't find the plug for it.... its supposed to be under the air filter, but the FSM is somewhat vague as to exact location.

I guess they figured their techs would know the engine bay by heart...

DlBass93, regarding your issue I suggest the folllowing troubleshooting steps:

1.Pull your fuel pump relay, remove the cover, replace it and try activating the trigger lever manually.(key in run position) If this activates your fuel pump, the relay is good and the problem is upstream.

2. Remove the relay and jumper terminals 30 and 87 with a jumper. I use a 16 amp fuse inline with the jumper for safety. This should activate your fuel pump. If it does not. The fuel pump may be bad, or there may be a break in the circuit.

3. If you can activate the fuel pump in steps 1 and 2, your problem is most likely in the LH ECU or the reference mark sensor. The reference mark sensor should be located under the air filter, right in the flywheel housing. This can be tested with a multi-meter.

This is as far as I got with troubleshooting, but there are some good sites going over the remaining procedures. I will edit this with a link I found useful.

congrats and cool car ! keep us updated !

rgds
Johnny

Glad you found your problem! Mine wound up being the battery was just a little too low, stuck the charger on it and vroom! Now I'm guessing my alternator is not operating optimally.