G40 running problems

[pinky]

Hey Guys,

Just following on my thread from CP really I thought it would be better to post it here. I had problems with my G idleing all over the place, poor fuel consumption and it keeps bucking at low speeds (which must look funny from the outside but it's really annoying in traffic)

Following andys and yoofs advice I changed the blue temp sender and the lamba probe which has helped but its still doing the same things. I really need to give it a good service but before I do that is there anything I shoudl specifically look at? Its fine on boost and pulls hard throughout the gears, when I slow down for traffic lights or sitting in traffic it will cut out or nearly cut out or just die completely. I have noticed the battery light will flash when its idleing badly so it maybe a electrical problem but this would be a stab in the dark. Im not sure if it is because my rear seats are stripped out but the fuel pump is really quite loud but im not sure if this is normal?

Any help appreciated! it would be nice to having it running properly before the summer fingers crossed

[Andy]

Is the ignition timing set correctly?
Have you stuck a meter on the battery to see what the voltage is with the engine running?
What's the CO pot resistance set to?

[PeteG40]

following andy - it could be alternator thats duff from the battery light and poor idle - you need to measure voltage across the battery

[pinky]

I am not sure about the ignition timing, I haven't checked the battery but I can do that this weekend. I think Marshall set the CO pot resistance slightly higher to even it out a bit but I maybe wrong another thing I will have a look at.

Thanks for the suggestions guys

EDIT : Another thing it doesn't do it in the morning till it warms up but I imagine if the alternator isn't charging correctly it will be pulling power from the battery so that might explain but I will check with the multimeter

[Andy]

It's hard to say what's going on - the battery light might just be coming on because the car's on the verge of stalling, so the alternator is dropping in and out.

The fact that it's okay when cold might be because the auxiliary air valve (what people call the ISV) is open, giving higher idle speed. The ECU controls idle by varying the ignition timing, so if the base timing is out (or you've got a spastic map in the car) the car might not idle.

It's also worth checking the closed throttle switch on the throttle body is working properly.

[pinky]

[quote pid=203 author=Andy date=1204901541]It's hard to say what's going on - the battery light might just be coming on because the car's on the verge of stalling, so the alternator is dropping in and out.

The fact that it's okay when cold might be because the auxiliary air valve (what people call the ISV) is open, giving higher idle speed. The ECU controls idle by varying the ignition timing, so if the base timing is out (or you've got a spastic map in the car) the car might not idle.

It's also worth checking the closed throttle switch on the throttle body is working properly.[/quote]


Yeah it does idle slightly higher in the morning then will drop under 1000 when it has warmed up

I shall get the ignition timing looked at how do I check the closed throttle switch is working correctly?

Thanks for the advice!

[Beavis]

Sounds like a weak alternator not pumping out enough juice. If the battery voltage drop benith 12.7v the ECU drops into a failsafe mode.
Test the battery voltage across the battery poles with all ancileries turned on to drain current. Even with everything trned on the voltage should be well above 12.7v.  Â£120 will buy you an genuine VAG alternator which will resolve the issues for a long time if voltage drop appears to be the issue.

[pinky]

Sorry for the late response, Just got the multimeter out and it read 13.3v (average) with nothing on and 12.4v (average)with everything on. The idle got alot worse when I turned everything on which I presume like you said steve put it in failsafe mode? Is the usual voltage alot higher than 12.7v ?

[hayesey]

sounds like a knackered alternator

[pinky]

Ok cheers for the replys, I shall give it a go

[pinky]

Another thing I forgot to mention is the car will sometimes cut out when I roll up to a set of traffic lights or just die when sitting in traffic when the idle is considerably bad would this be because of a lack of power?

[Beavis]

[quote pid=772 author=pinky date=1207743891]Another thing I forgot to mention is the car will sometimes cut out when I roll up to a set of traffic lights or just die when sitting in traffic when the idle is considerably bad would this be because of a lack of power?[/quote]

Classic traits of low voltage from the alternator, combined with the low voltage readings I think it is safe to say you have to dig deep and buy a new unit.

[pinky]

Cheers Steve just wanted to make sure

[vwmk3jon]

exact same thing as mines doing  

[pinky]

Its a royal pain in the a$$ but I should have a alternator arriving tomorrow and will hopefully be fitting it Saturday

Have you checked yours with a multimeter jon?