Clare Pascoe
New member
My 928 S4 (D-reg) has been suffering from an intermittent fault for a few months. I'm emailing the forum to see whether others' have had the same issue; and to find out what was the root cause for your car - in the hope it gives us a fast track to check likely causes (rather than investing hours chasing a needle in an 'electrical rats nest' of a hay stack!)
The garage (AW Motorsport, Southbourne, Hants) are Porsche experts, and I cannot fault them - but they rarely see 928's so are becoming stumped. They confirm the engine runs beautifully, and they are convinced the fault is electrical; but as much of the electrics in the car are original, they're not in great shape - and once tampered with, tend to require replacing.
I'd be very grateful for any thoughts. Thank you, Clare
Details:
- The fault doesn't occur when the engine is cold;
- Once up to temperature, it faults every 30mins or so.
- The fault presents as a mis-fire, where for a split second it seems like the engine is going to cut out, with a brief loss of power. Latterly this produced a few impressive back fires!
In a bid to find the fault, the following has been done:
- Replaced Ignition Module (original fell apart when it was checked!)
- Replaced TDC Sensor (part no. 94460611500) & connection plug (female part) to wiring loom
- Road tested to check the relays (the indicator relay and a heat exchange (?) relay seemed to be faulting?)
The result of the above, is that the car is running better, with no back firing - but it still faults, although less frequently.
I've been advised to:
1) have an electrical specialist spend a day with it, fault finding - but this could lead to a whole can of worms; and cost a lot of specialist time before anything is actually resolved....
2) fit a new fuse board, with new relays; but at £83 a pop for 12 relays, this isn't a cheap option unless I know it will work. Unless there's a way to do this economically?
Thank you again!
The garage (AW Motorsport, Southbourne, Hants) are Porsche experts, and I cannot fault them - but they rarely see 928's so are becoming stumped. They confirm the engine runs beautifully, and they are convinced the fault is electrical; but as much of the electrics in the car are original, they're not in great shape - and once tampered with, tend to require replacing.
I'd be very grateful for any thoughts. Thank you, Clare
Details:
- The fault doesn't occur when the engine is cold;
- Once up to temperature, it faults every 30mins or so.
- The fault presents as a mis-fire, where for a split second it seems like the engine is going to cut out, with a brief loss of power. Latterly this produced a few impressive back fires!
In a bid to find the fault, the following has been done:
- Replaced Ignition Module (original fell apart when it was checked!)
- Replaced TDC Sensor (part no. 94460611500) & connection plug (female part) to wiring loom
- Road tested to check the relays (the indicator relay and a heat exchange (?) relay seemed to be faulting?)
The result of the above, is that the car is running better, with no back firing - but it still faults, although less frequently.
I've been advised to:
1) have an electrical specialist spend a day with it, fault finding - but this could lead to a whole can of worms; and cost a lot of specialist time before anything is actually resolved....
2) fit a new fuse board, with new relays; but at £83 a pop for 12 relays, this isn't a cheap option unless I know it will work. Unless there's a way to do this economically?
Thank you again!
