Another wont stay running
 

Hi, I picked up an 82 Weisach 5 speed at a sheriffs auction a few weeks back. The car was sitting for a while, I'm guessing at least a year or more. I was told it was driven into the auction site then was there for 2 weeks and wouldn't start after that.
Brought it home and discovered the fuel pump had pooched. Replaced it and the fuel filter. The gas was pretty bad so I drained it as well. The car was pumping gas all the way to the fuel rail tap but would not fire. Checked the spark and it was weak. Took off the cap and rotor and found they were badly corroded. Should be replaced but cleaned them up and got a good spark. Car began to fire but would not stay running. Jumpered the fuel injection relay and the same result. Bought a noid tester and the injectors are getting signal, at least one. Didn't check them all. So fuel is making it to the cold start and getting injector signal. Fuel injectors clogged? Is there any other possibility before I remove them and get the cleaned tested?

Thanks, Joe

Joe,
Congratulations on your acquisition. Clogged injectors would be my bet. If you use starting fluid, will the engine stay running?

If you send the injectors to be cleaned, make sure to clean out all the fuel lines and injector rails prior to reinstalling them. I would also remove the fuel level sender and take a look at the condition of the fuel tank. It might need to be removed and cleaned as well. No sense in clogging clean injectors again.

IIRC, there were only about 205 Weissach cars made in 1982. If not today, the car should be worth a lot more down the road due to the scarcity.

how close to starting does it get - does it run a couple of seconds or just never really catch - you could remove the cap from the end of the fuel rail and run the pump to flush out any old fuel that might still be in lines - be careful as gas will really come out - if it did indeed run 2 weeks ago i wouldn't think the injectors would clog in that period of time... but it could be that little bit of running pushed all the gunk that had accumulated in lines to the injectors - could also pull a plug wire, crank it a few seconds then pull that plug to see if it's wet with gas - good luck

928 Brotherhood -
 

Hey Targa - Welcome to the fraternity of the 928 brotherhood. :) The 928's are known for an assortment of voltage drops within it's wiring harness which can make her a real bear to start at times. As a new owner one of the 1st projects you will probably need to tackle is to clean all the major Ground points through out the car.

It is good sign that your baby is trying to start but it sounds like you may have a border line working voltage during start at the fuel injection computer (Rt Hand Kick Panel - Passenger Foot Well) and/or ignition box (Below Rt Hand Radiator Hose - Passenger Fender).

There may be other areas to also address as well but you might initially try :

1. Make sure your Primary Battery is fully charged -
2. Clean both ends of the Primary Battery Cables -
3. Clean the Jumper Post Connections - Passenger Inner Fender -
4. Clean the Two FI Grd terminals on Top Rt Hand Valve Cover -
Small Brown Wires attached to "Porsche" letters
5. Attach a Second Hot Battery to under hood Jumper Post -
6. THEN try to start the motor using 10 - 15 second cycles - with lots of rest time between cycles - long term cranking over a stuttering 928 motor takes a lot of umpf -

To eliminate any potential relay issues - you may also jumper the fuel pump relay socket and the socket for the power relay for the Ignition Box. CAUTION - Keep and eye on your rubber fuel lines back around the fuel pump and under the hood for any sign of a leak. You will want to replace these lines before much run time.

Good Luck and Keep us posted - Michael

thanks, will be trying on the weekend. Working on the 911 tomorrow

Joe

Sounds almost like low fuel pressure. The pump should prime for a couple of seconds when you start the car so the pressure could be enough to get it going but not enough to keep up once it's running.

In addition to the grounds as mentioned, this also sounds like a green wire issue. If the cap and rotor were so bad, the green wire is likely compromised as well. It sends a signal from the ignition control to the rotor. If it is old and brownish looking, replace it. It is not cheap - over $100, but the car won't run without it. And no, you cannot just take any old wire and splice the connectors onto it. The green wire is a coax style wire.

Look at my video....I fought this for almost a year, and ended up being the fuel injection relay was failing, and finally failed altogether. Also replaced all the fuel injection connectors.

Your injectors should be at least clean enough for her to run crappy....

Count on doing a CE panel refresh, vacuum lines, and please do all the rubber fuel lines (I recommend doing this first) so she doesn’t burst into flames. Feel free to pm me if you have any questions.

Also, make plans to do the Timing Belt and Water Pump. Your '82 is probably a non-interference engine, but if you are having these other issues, chances are that hasn't been done in a very long time.