Hi if anyone can show some light on my running prob it be great.

I have a intermittent starting & idle problem. And would like to explain what ive done and wonder what i can look for next. any help would be much apprecaited. I havent really got my hand dirty on a 965 before but i bought Adrians book and its been very very helpful. thanks.

A few months ago it sometimes 'hunt' by idling lower and back up to 900rpms. it did this sometimes and the other times it was rock solid.
After this i was driving at 70 and my car just cut out like id turned of the igntion key, i pulled over and the car wouldnt start- it would just fire and die straight away. so i left it 10minutes and tried it agian, it fired up no problems and it started up all weekend.

Recently now the problem got worse and it sometimes starts sometimes doesnt and same goes with the idling. Sometimes its starts and idles rock solid, sometimes starts rough idles, sometimes starts and slowly ides out and somtimes doesnt even fire.it is regardless of a cold/warm/hot engine.

I checked the fuel relay/fuse and the relay looked old (the top part came off) so i replaced it but still no difference to the starting. One observation was that if i bridged the connections i could hear front and rear pumps turn on but when the i turn the key with the new or old relay in i can only hear the front pump... so i dont know if thats normal but either way even when i can hear both pumps by bridging it still wont make the car start/run better

Ive checked for spark once and there was one. Im just not sure what i can try next, i understand
it needs fuel, air and a spark. so if the pumps work i guess theres fuel, is it some air leak? but its very intermittent.
Esp if one day it fires up fine then i drive it and park up for a few hours it probably wont start again.

Ive checked the intercooler o ring and that is on properely and ive checked
other pipes for cracks etc. all seem ok.

If the are starts i can keep my foot on the gas to keep it going if its going to die. The performance & boost are perfect.

Another point that i dont know if its realted it that the fuse from the engine compartment (no 2 from the rear) blows. If i replace it i get a wierd loud 'monster' sound from around the turbo area... (with ig key on and/or engine running) then the fuse blows and the sound goes. i dont know what it is but it seems not to have any effect on the running issue.

Please help
Many thanks
Miles 965 '94 turbo

 

I may be wrong but it sounds like mice.

I would start by check your wiring harness. Mice love the warmth and comfort of Porsches. Sometimes they eat at the wires insulation and leave the wires exposed. This can cause all sorts of weird intermittent problems. Check around the fan housing and look for straw or other foreign objects that don't belong. This could mean they made a nest in your engine.

If that isn't the problem I would get an exorcist

Just kidding, keep us informed.

 

Thanks Colbat, lovely colour man. But i dont think any mice have found an expensive home! i recently taken the intlet manifold off (after issues) and checked alot of pipes and wiring but ill let you know what the result is.
Cheers
Miles

 

Miles,

I would take it to a specialist / OPC for a full diagnosis - it should be fairly hard to trace DIY since it sounds intermittent, and there are so many variables/parameters that could be wrong. Keep us posted on your progress.

All the best and good luck

Emilios

 

Miles,

I'd hazard an educated guess that the 'monster' noise is the rear heater fan on its way out. I had pathetic airflow in the cabin and checked the fan fuse in the engine bay. It had blown. When I replaced it the fan starting working again, and still does, but some cold mornings on start up it sounds like the rattle of chains for a split second.

 

Thanks and yes the heater is crap!
I took the dist cap off to have a look and one point is scored and a bit broken so im going to replace that. i will comment on the results to you guys.cheers Miles

 

Sounds exactly like when I had an air leak. My intercooler pipe had worked loose, and gave exactly the problems you described. I'd also check for vacum leaks. Plenty of tips on the various boards on how to do that quickly...