Starting Problems

Ben944 · Feb 9, 2015

Hi

For some reason my 944 stop runing while driving at 30mph then wouldnt start again sparyed some jump start then ran for 5 mins and cut out again now all it does is start for 1-2 seconds then cuts out but i can rev it for that time
I have replaced DME fuel pump fuel filter FPR air flow meter still no joy theres spark to the plugs so not coil or dizzy am i missing something please help as its driving me mad and getting expensive

Thanks

robwright · Feb 9, 2015

DME (blue) temp can sometimes cause starting issyes.

Ben944 · Feb 10, 2015

Was thinking it might be the crank sensors anything else I need to check Thanks

peanut · Feb 14, 2015

not likely to be your crank position sensor (CPS) Ben otherwise you'd have no spark either . The ECU pulses both your ignition and the fuel injectors. Apologies for stating the obvious but have you tried fitting a 3x wire bypass in place of the DME relay yet ? as per Clarkes Garage guide ? The bypass will power your DME and power your fuel pump, injectors and sensors etc .It eliminates the DME relay being the cause of the problem I don't know what model you drive is it early or post 1985 ? the later cars only use one combined crank sensor for crank speed and crank position (TDC) You should see a very slight flicker of the tacho needle when cranking to confirm that the CPS is working ok. With all this rain we have been having lately I'd also check that no water has got onto the ECU via the bulkhead scuttle due to blocked drain holes . You might need to check your fuel pressure relief valve FPR to make sure that you are not losing fuel pressure as it does sound like the FPR might be releasing fuel pressure

Ben944 · Feb 14, 2015

Thanks for the tip I have done the bridge of the dme so rules that out I did check the ecu area a few days later when I was dry but did cut out in the pouring rain so I think only the ecu can be at fault now The car is a 1989 2.7 but has 2 sensors on the bell housing Thanks

Ben944 · Feb 14, 2015

The fpr has been changed but might still give the rail a test Thanks

peanut · Feb 16, 2015

there is a non return valve in the fuel pump which could be leaking allowing a drop in pressure or you could have a leaky injector but its usually the FPR valve . A pressure /leak down test would eliminate all three and you could do a flow rate test at the same time

Frenchy · Feb 17, 2015

The radiator cap kinpin which turned out to have some corrosion caused all sorts oof starting grief and running problems, it would start and run fine then cut out and refuse to start, i started to get in to deep, looking at crank sensor values, ecu's, afm's etc Turnied out to be the dizzy cap when i went back to basics [

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peanut · Feb 18, 2015

you're right Frenchy there is no substitute for being systematic when troubleshooting problems but like you say most starting and running problems are very simple . Usually lack of use and poor connections or injectors sticky with laquer

Frenchy · Feb 18, 2015

Just read my post "radiator cap had some corrosion" meant to read distributer cap........doh ! that said, go back to basics, i also had a spark at the plugs which threw me, i realised it was only a weak spark.