wewu Posted 6April, 2022 Report Share Posted 6April, 2022 Hi guys help needed 1990 964 the problem is for no reason it cuts out and will not start it turns over but will not fire leave it 2/3 hours and away we go as sweet as a nut it started on a trip back from france changed dme relay genuine porsche one and replaced fuse have done over 300 miles and it failed twice more not sure what to look for next any ideas please thanks byron Quote Link to comment Share on other sites More sharing options...
Rod C Posted 6April, 2022 Report Share Posted 6April, 2022 Had the same issue with a 924 and it ended up being the fuel regulators. Quote Link to comment Share on other sites More sharing options...
Peter M Posted 6April, 2022 Report Share Posted 6April, 2022 2 hours ago, Rod C said: Had the same issue with a 924 and it ended up being the fuel regulators. Rod, A 924 uses K Jetronic and a 964 uses L Jetronic so unlikely but get your point it could be fuel related. Byron, How frustrating would this be and even more difficult to trace! Next time it stops, I would first check you have spark by pulling a plug lead and have some one turn the engine over while almost grounding the lead. If you haven't a spark, that at least gives you the reason and where to start looking further but can't imagine what would cause that to fail intermittently. Next I would then check your fuel pump is working. If you jack the front of the car up, there is an inspection plate that can be removed and you should be able to feel the pump operating when the ignition is on. If it doesn't feel like its operating, I would then check the electrical connection to establish there is power to the pump. Whilst you have replaced the DME relay, I'd still check you can feel the relay is responding to the ignition being turned on and off. My money is on the fuel pump given the failure you describe and if the pump is still the original pump I would just replace anyway as they don't last forever, aren't that expensive, pretty easy to get at and this is much easier done in the comfort of your garage rather than on the side of the road. Good luck and report back what you find it to be please for our collective education. Quote Link to comment Share on other sites More sharing options...
autojack Posted 7April, 2022 Report Share Posted 7April, 2022 My 3.2 911 had a fuel pump failure. Before it happened I had a couple of no-start issues like you describe, before it finally failed and left me stranded. In my car (1988) I had to make a jumper lead to power the fuel pump with the key on. Once I did that, I heard nothing. Then I smacked the pump, it buzzed for a few seconds, then stopped. Bingo. Quote Link to comment Share on other sites More sharing options...
LeeM Posted 7April, 2022 Report Share Posted 7April, 2022 Fuel pump would be the first thing I would look at Quote Link to comment Share on other sites More sharing options...
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