QuestionI have recently purchased the 82 928. The car had been sitting for years. I have cleaned all the fuel lines and fuel tank, replaced the fuel pump, filter, regulators, thermo time switch, plugs, and cleaned the injectors. The car starts for 4 or 5 seconds and konks out. It seems to be getting gas and the cold start valve seems to be working. I have had the car going successfully two or three times after trying many times after many experiments.
Any ideas or tests i could experiment with?
AnswerHi Tim. Sorry I didn't get back to you sooner.
If you believe fuel is getting there,,,and I think so too because it'll run for a few seconds...then there are two places to look.
1. If you haven't already checked this, find the fuel return line and check to make sure it's clear. The pressurized fuel doesn't all go to the injectors. some of it bypasses them and returns to the fuel tank for another trip. This is mostly a momemtum/gravity thing...there's no pump pushing the fuel back that direction. After all that time, I'd check the line.
2. The symptoms, again if you have fuel, sound just like a faulty air flow meter. Faulty usually means greasy/gunked up. I don't have a 928 reference manual so I don't know what Porsche calls their air meter on a 928, but basically, here's how it works. The engine sucks in the air on the intake stroke through the air filter. Somewhere past that and before the intake manifold is the air flow meter. It's really just a door (or a flap). The wider the door is open the more air is flowing in. The door's position is monitored and this info is sent to the computer. That way, the computer can add fuel at the proper rate to get a consistent air/fuel mixture. If we assume your door is stuck in one position, the amount of fuel squirted at each injector is based on that position...probably wrong for the circumstances. The computer will shut down the car if it can't get the air/fuel ratio where it wants it.
Let me know what you find.
Davepostion
