Sods law strikes

[jonnyporsche]

To add to the woes of the corner damage in another thread I now have a running problem. This sounds like the well known DME relay problem but it isn't that, I'll expand. After running for a short distance after starting, the engine cuts out totally, not a cough or a splutter just dead, all other electrics working fine, leave a minute or two and it starts fine and runs with no problems. I suspected the DME relay so replaced it with a nice new one, still does it [:'(] I know its an old chestnut but where is a good place to start. Any ideas are welcome.

 

[white944]

Crank sensor?

 

[jonnyporsche]

Crank sensor?

That's a good call. Thanks
More please

 

[944Scott]

Crank sensor was also my first thought.

 

[Elliot]

definitely crank sensor

 

[blade7]

FPR.

 

[MickHudson]

Crank sensor

 

[Frenchy]

FPR. End of message.

 

[jonnyporsche]

Thanks all for your suggestions it seems its crank sensor or FPR, FPR or crank sensor,,,,,FIGHT[]
Is it right that if there is fuel in the vacuum line then the FPR is duff?
Haven't had time to look at the problem yet hopefully can investigate this week-end.

 

[jonnyporsche]

I have just replaced the FPR with a nice new one. Engine started but died, now it won't start at all, is it onto crank sensors now or am I missing something?

 

[blade7]

AFM.

 

[944Scott]

My money is still on the crank sensor.

 

[Frenchy]

Maybe the ECU breaking down after some heat.

 

[jonnyporsche]

Still will not start so here I am at Crank Sensors. Mechanicals I can do but electrics are a dark art to me, so following Clarks Garage for testing the sensors with a multi-meter I get the following results which to me don't match up with Clarks but I don't know what they do mean. Help me please.

 

[jonnyporsche]

I've done a bit more reading and I found that the resistance of the sensors should be 900ohm's so if the decimal point is moved on the display (me setting the meter wrong?) they are not far off, can someone confirm this please.

 

[peanut]

could do with a bit more information really.[] It could be practically anything! Too high fuel pressure, too low fuel pressure, faulty engine temperature sensor ,water in the ECU, poor earthing points under the dash for the DME relay and ECU unit , no spark etc .

If you have fuel in the vacuum lines then your Fuel pressure relief valve needs replacing . if the engine has to turn over a lot before starting when cold, then that could suggest the fuel system is losing pressure (FPR) Easy enough to do a leak down test

If you turn the engine over, you should be able to see the tacho needle jump slightly if the crank sensor is working.

Have you tried removing the DME relay and fitting a 3x wire bypass yet? (see Clarkes Garage or search on this forum)
That will at least eliminate the DME relay being at fault and it should power the ECU , injectors ,sensors, fuel pump etc . If the engine then continues to run ... it will narrow down the source of the problem

 

[jonnyporsche]

 

[jonnyporsche]

could do with a bit more information really.[] It could be practically anything! Too high fuel pressure, too low fuel pressure, faulty engine temperature sensor ,water in the ECU, poor earthing points under the dash for the DME relay and ECU unit , no spark etc .

If you have fuel in the vacuum lines then your Fuel pressure relief valve needs replacing . if the engine has to turn over a lot before starting when cold, then that could suggest the fuel system is losing pressure (FPR) Easy enough to do a leak down test

If you turn the engine over, you should be able to see the tacho needle jump slightly if the crank sensor is working.

Have you tried removing the DME relay and fitting a 3x wire bypass yet? (see Clarkes Garage or search on this forum)
That will at least eliminate the DME relay being at fault and it should power the ECU , injectors ,sensors, fuel pump etc . If the engine then continues to run ... it will narrow down the source of the problem

Thanks peanut for the suggestions but I have more problems now (see my other thread) so it looks like that it for the summer[:'(]