Audi Coupe ACE Problems

[Johniewalshe]

Hi all wondered if anyone can help.

I have a 95 audi coupe with ACE engine.

sometime when I was driving the power would just die, then I'd put the foot down fully it would take off. this used to happen off and on put not a big problem until...
a week or so ago it became more frequent until it just was constantly like that.

I thought it might be the throttle position sensor so I change the throttle body and no change.

What I have noticed so far

Garage tested emission and said it was running very lean they checked the lamda and its good,

If I plug out the temp sensor on rear of head it runs, does not idle well but runs. change the sensor no different

checked the idle control valve, I can measure 12v across the plug, but when I plug it in the voltage drops. if I check voltage between the positive terminal and the supposedly negative going to the valve, once I plug it the voltage drops

Cleaned the valve, connected direct to battery and if functions, but not change re voltage drop.

check continuity between the negative and the engine: with key off 0 ohms, key on 12 ohms and with engine running 600 ohms

maybe this is normal, but what I am thinking is something is drawing down my earth, and therefore analogue signals sent to and from the ecu are not correct

once the temp sensor is unplugged the ecu thinks engine is cold and sends more fuel??

got it pluged in and no fault codes recorded.

Any ideas

Thanks

[Skull]

the fuel pressure regulator? Check the little L tube that goes from the airbox to the FPR, maybe it is leaking...

[mike74]

When was the last time the fuel filter was changed? Maybe also check the voltage to the pump too as well as its earth, just in case there's something amiss. To rule out a dodgy engine earth try connecting a jump lead from engine to chassis and go for a drive. Hope you get it sorted anyway

[Johniewalshe]

Thanks, I'll check that. Is the fuel regulator purely pneumatic. How does the ecu effect the fuel ratio. I taught the fuel was only increased/decreased by the flap in the fuel distributor.

[Skull]

the ACE ecu is a smartass, it has maps and so it can also be chipped. it can also learn your driving style and sets itself by it...