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Thanks, I'll check it out. My immediate reaction is that although the car has started just fine most of the time, there have been a couple occasions when throttle input was needed to keep it on immediately after starting. Could be something similar.
When you first start it cold and it is at high idle before settling down to normal idle. Started it one time in winter to move it but stalled it immediately (clutch). Had a hard time getting it started and it blew out a big smoke cloud.
Thanks, I'll check it out. My immediate reaction is that although the car has started just fine most of the time, there have been a couple occasions when throttle input was needed to keep it on immediately after starting. Could be something similar.
I experienced similar symptoms months before my issue.
Well Ralph's generously donated DME does not seem to have done the trick. We'll see for sure if the DME is the issue in a couple days when the replacement comes in the mail, but if it doesn't turn out to be the problem what's the next thing I should try?
Sorry to hear that, I had hoped for a different outcome.
Sorry to hear that, I had hoped for a different outcome.
So had I, but oh well. I really appreciate you taking the time to meet up with me and pass over the part. Time for me to embark on the rest of the diagnosis journey!
Does this car have an Porsche Drive Block immobilizer? If so, you have Porsche key fob remote controls for unlocking the car.
The control unit may have developed solder faults, causing intermittent power supply to the ignition modules. I have seen this several times, especially on the early version of the immobilizer used in '94 and '95/1 models. The Drive Block control unit is placed under the driver's seat, adjacent to the Motronic engine control unit.
Cheers,
Tore
As far as I know it is not equipped with a drive block immobilizer. I don't have an electronic key fob, and it appears to only lock and unlock externally with the keyholes on the doors.
Do you smell fuel at the exhaust tips when you crank it over?
If not, check the fuel pressure. You can access the Schrader valve without having to remove any components.
Fuel pump failure is not uncommon. (Bosch 580 464 058)
If you do have to replace the pump just make sure you empty the tank first and do not rely on hose clamps to stop the flow on the tank to pump hose. I’m an idiot and got soaked.
Do you smell fuel at the exhaust tips when you crank it over?
If not, check the fuel pressure. You can access the Schrader valve without having to remove any components.
Fuel pump failure is not uncommon. (Bosch 580 464 058)
If you do have to replace the pump just make sure you empty the tank first and do not rely on hose clamps to stop the flow on the tank to pump hose. I’m an idiot and got soaked.
This. I replaced my pump at about 100k. It was noisy and I think led to the DME relay failure I saw.
Did a de-flooding procedure (cranked car three times for a couple seconds each with DME relay removed) then attached a jump-box to the battery and let the fuel pump prime for 30 seconds to a minute and then started the car. Started right up, and ran just fine until I disconnected the jump-box from the battery. Removed negative cable, then removed positive. As soon as positive cable was removed from the battery, there was a small spark on the nut holding the the battery cable clamp to the terminal, and the car instantly died. We attempted to start the car again, and now when you finish cranking and turn the key back to the off position, the spark happens again in the same place, and the car won't start. We tested the battery again and it tests just fine.
Pull that battery out and get it load tested. Then check your fuses. Chances are that you have a bad battery. I'd do both of those prior to pulling out the alternator. If neither of those pan out, time to look at the alternator...
How did you prime the fuel pump? pull out the DME relay and jumper it? Look closely at that relay as well....
I just wanted to share the resolution to this as it’s at my shop (Series4) right now. The car was displaying symptoms of an immobilizer error, however this car was not equipped with one. The DME was not sending any fuel or ignition back to the engine which made me think maybe the computer got fried when it had been jumped. I noted that he said the car shut off as soon as he took the jump leads off of the battery, and upon closer inspection I found that the often-forgotten DME wire was loose and the car would start with jump leads because the jump box was clamping that wire to the terminal only when it was hooked up and would disconnect when removed. Just goes to show, it’s often the small things!
02-04-2020 | 07:00 PM
