G60 Running fault (Rallye)

[whinesallday 0]

I'm working on a rallye for a friend who bought the car which is absolutely mint but runs really badly. Once warm the car will not hold fast idle sat stationary, i.e. throttle at same position holding at 2500rpm for around 5 seconds then just dies off until it's just about to cut out then pick up the revs again. Up the road is pretty similar, dies down and then picks up again. I have set all timing and emmisions up correctly, disconnected lambda probe, chaecked cat for blockages, replaced cooant temp sender and still can't get it to run any better. Compressions are ok and new plugs fitted. With the coolant temp sender disconnected I can hold the revs high without it dying off? Has anyone got any idea's as I'm pretty stumped? Cheers

[Supercharged 2]

With the BTS disconnected you are in timing mode - ie no advance by the ECU

 

I'd maybe try a new ECU...

[whinesallday 0]

Cheers, would a PG engine g60 ECU from a corrado run the 1H engine or are there programming differences, thanks

[Supercharged 2]

I think so yeah or at least to test... the rallye ECU has a higher reading 1.5 barr map sensor

[whinesallday 0]

ECU doesn't seem to have cured this still the same as before. Can't think what else would be effecting the running so much that would be altered by putting it into timing mode? Any more ideas guys :)

[Supercharged 2]

Lambda wiring would be the next thing to check...

[whinesallday 0]

Am i right in thinking it should run ok without the lambda probe connected, just won't make closed loop adjustments? Thanks

[Yandards 0]

Am i right in thinking it should run ok without the lambda probe connected, just won't make closed loop adjustments? Thanks

 

Yeah that's right.

 

As for your idle issue, is the car stock or modified?

 

Is the problem a result of a recent mod or was it ok before and just suddenly started mis-behaving?

[whinesallday 0]

As far as I can tell the car is stock, it's a rallye that was taken in by a friend for full respray and customer never returned. It does seem just like a sensor playing up but can't seem to get it running correctly whatever

[Yandards 0]

Is the problem only there during the normal running phase or it is apparent through the cold start and warm up phase? (ECU goes onto Lambda adaption at 70 deg C coolant temp)

 

I guess the car has been parked up for a while and not started given the way your friend got the car?

 

I also assume that the car behaves at normal idles? (800 rpm plus or minus 50 rpm)

 

If that is the case it sounds like there is not enough fuel getting to the injector rail at fast idle, this makes sense if the car has been parked up for a while as it is possible the fuel filter has become gunked up.

 

So next course of action is a fuel pressure test if you have the kit, you should be getting 2.5b at idle on the rail (measure at point where after fan run on pump sensor connects) then remove the vacuum hose line that goes onto the inlet manifold from the FPR, pressure should now be around 3b. If that is no good I would change the fuel filter and then finally look at the fuel pump itself, the seals on the pumps have been known to perrish over time preventing the pump from operating correctly - you can replace the seals if the rest of the pump is ok.

 

As for why it is ok with the BTS unplugged, in timing mode all the adaption is removed, so adjustments for coolant temp and CO become default values, this should lead to an increase in injector duration which despite the fuel pressure being low would give you enough fuel to run.

 

This is all a bit of guesswork without looking at the car and I can also recommend replacing the ECU vacuum line that runs from the throttle body to the ECU, this should be exactly 1 metre in length and needs to be the correct VW specified hose to ensure the MAP sensor in the ECU gets good data.

[Pieter7 10]

Hi I have a g60 with similar problem and was hoping you might be able to give me some advice.cheers

[Grrrrallye 0]

Had a few issues with my Rallye that sound similar.

I would have suggested swapping the 2 coolant sensors over, but you have done that

My next check is the vac line that goes to the ECU, it needs to be a specific length 1m if i remember correctly, mine was intact my had perished and caused issues, my be worth a look

also down behind the throttle body you should find 2 small screws that adjust the idle etc, if the screw falls out - they have a tenancy to, all hell breaks lose

[Pieter7 10]

Cool it is a start at least,one of those screws did come out and is gone. I have a bolt in there but definintly not the right one. I am out here in south africa and no one here know any thing about these rallyes. How do i go about ajustment once i find the right screw.

Ps thanks alot for your response.