another no start gremlin !

[Gazmitchell]

hi all, so I've been doing bits n bobs to the car recently, -( s2 coupe )as it had a stutter, misfire issue in low revs/ gears, so I've re placed all five coils and renewed all wiring - into plugs with new pins etc, ( all wires inside heat resistant coverings was knackered ) put all back together started ran sweet and no misfire , smooth ...great !!! .. went out earlier to tescos, was raining , ( may be relevant ! ) parked it, locked it, came back half hr later and wouldn't start. just turning over on the key, like immobilizer still on. the car has a cobra 7925 fitted as well as the standard one, anyway towed it home , got on the drive and it started ! and did everytime I wanted it not to. now its in the garage left hour or so and again just turning over again..

so wonder if its a immobilizer issue as its never had this starting prob before, but don't wanna mess with alarm etc if its not that ... is there a way I can bypass immobilizer/ fuel pump etc and try it ? I had planned to go away in it weekend ( first time since buying it !!) now im prob gonna leave it at home as cant trust it lol...

[Error404]

Test the hall sender

[Gazmitchell]

Hi mate - did all the coils and wiring as we chatted a while back ? carefully wrote down exactly which wire went to what pin etc !!?? no splicing etc .. so all good there, and as I said , started ran like a dream . no issues. now no start !? where's the hall sender located ?

[kulster]

On mine it was the fuel pump

[kulster]

At first it randomly didn't start while the wife was out in it, so recovered it in to my work and it started perfectly, all week I kept the car at work and started proberbly 50 times from hot and cold with no issues, gave it her back and day later it wouldn't start, removed the pump put power to it and nothing, so gave it a tap and it kicked in, replaced it with a genuine one from TPS

[Gazmitchell]

Yeah , thanks.. gonna check hall sender and pump first and pump relay... was fine then nothing,... gonna charge battery fully first tho...

just another thing I noticed , while cranking engine over I've a red oil can warning light on computer coming on, - there is def oil in there, - and no leaks.. any ideas ? will that be oil pressure?

[Gazmitchell]

So further to this , I've had a multimeter on the fuel pu p and it's showing 10.2 v on cranking, is this enough.? And ivehad the relay cover off and touched the contacts inside and I can hear like air squirting at the injectors , so fuel, but had the plugs out and they're dry.... .. ?

[UrS4boy]

So further to this , I've had a multimeter on the fuel pu p and it's showing 10.2 v on cranking, is this enough.? And ivehad the relay cover off and touched the contacts inside and I can hear like air squirting at the injectors , so fuel, but had the plugs out and they're dry.... .. ?

Stimulating the fuel pump via the fuel pump relay only pressurizes the fuel rail, it does not open the injectors. That is controlled by the ECU. I don't know what you heard exactly but it should not have been fuel spraying into the head, hence dry spark plugs.

Fuel injector wiring info:

http://forums.quattroworld.com/s4s6/msgs/90802.phtml

[Gazmitchell]

Stimulating the fuel pump via the fuel pump relay only pressurizes the fuel rail, it does not open the injectors. That is controlled by the ECU. I don't know what you heard exactly but it should not have been fuel spraying into the head, hence dry spark plugs.

Fuel injector wiring info:
http://forums.quattroworld.com/s4s6/msgs/90802.phtml

Ah that explains it.. Exactly what I heard... Is 10v at the pump enough ?

[Gazmitchell]

Test the hall sender

Was indeed the hall sender ."

[chezz]

Stimulating the fuel pump via the fuel pump relay only pressurizes the fuel rail, it does not open the injectors. That is controlled by the ECU. I don't know what you heard exactly but it should not have been fuel spraying into the head, hence dry spark plugs.

Fuel injector wiring info:
http://forums.quattroworld.com/s4s6/msgs/90802.phtml

Is it not the fuel returning back to the tank when the fuel pump has been bridged?...the pump is running continously and therefore if the fuel is not being consumed by the engine - it has to return to the tank.

[UrS4boy]

Is it not the fuel returning back to the tank when the fuel pump has been bridged?...the pump is running continously and therefore if the fuel is not being consumed by the engine - it has to return to the tank.

Correct. I am not sure what your point is. I suggested that just having the fuel in the fuel rail does not equal fuel out of the injectors. The fuel rail can be fully pressurized and, if the injectors are working properly, no fuel coming out of them - until the ECU decides that is appropriate (i.e. time and duration).

[chezz]

Correct. I am not sure what your point is. I suggested that just having the fuel in the fuel rail does not equal fuel out of the injectors. The fuel rail can be fully pressurized and, if the injectors are working properly, no fuel coming out of them - until the ECU decides that is appropriate (i.e. time and duration).

My point is that you did not know what the noise was...please do not try to 'Bu11sh1t' me.

[UrS4boy]

My point is that you did not know what the noise was...please do not try to 'Bu11sh1t' me.

Excuse me? I knew the noise was NOT the injectors. After that I didn't care.

[chezz]

'I didn't care' Tell it to the judge lol!