g60 driving me up the wall

[mcramsay 10]

hey guys, this is my first post, definatley not the first time ive been on the forum though...been pouring over all the hundreds of posts on G60's not idleing well and stuttering and hesitating....

 

I bought my first g60 4 weeks ago, a really mint looking one from my boss at work, however its turned out to be a whole host of trouble. so far ive had to replace the clutch master cylinder, fit a jetex exhaust, ive had the front engine mount snapp and the engine hit the bonnet (which has ruined a bonnet that was resprayed 3 weeks ago) quite alot of work for a car ive not had that long.

 

the main issue ive had is now and then the car will hesitate at low throttle, and then suddenly fly past 2000 RPM. i thought it might have been a fuel pressure regulator issue so i changed that (i didnt suspect a lambda sensor fault as it has just been fitted with a new one)

 

the problem then started to get really bad, and it felt like that car was loosing 2 cyliners at certan points when returing to idle making it undrivable. because of this i splashed out and purchased a new dizzy, Co pot and knock sensor. fitted them all today and the car was still rough. when trying to set the timing the engine nearly died everytime i unplugged the blue coolant sensor (having read some ware before that the digifant can only compensate for one buggered sensor) this made me believe i still had a fault someware. after lots of poking with a multi meter i found that the signal for the lambda to pin 2 of the ecu plug was very intermittent, some times it was good, most of the time not, which would make sense with the running issues ive had (IE mostly cutting out when the car is being driven (wires moving around) and only when the car is hot).

 

anyway ive done a repair on the lambda and i can now unplug the blue sensor and the engine is still revable (meaning to morrow during the day i can set the timing.(i hope)

 

what i wanted to know is the idle is bang on 1000 which is a bit too high, will i have to ajust the co pot to get a certain resistance across pins 1-3? its come straight brand new from VW. i meansured the current resistance which is just over 1000 ohms. should i ajust this?

 

also calling all digifant gurus does it sound like im on the correct track? (ive checked all vaccum leads and ground points also)

 

sorry for a HUGE first post. i just needed to vent my fustration and hopefully be told im doing things logically and getting results...my girlfriend doesnt have a clue you see.

[VR6 0]

I can't offer much help but I can say welcome to the CF! :)

[carrots 1]

i am no expert but sounds like could be sucking air somewhere

[leeeeshad 0]

Try replacing the ecu relay (number 30 or 33) that sorted all sorts of rough running on mine.

[daniel 10]

same as above i had kind of the same problem changed the ecu power suply relay and that sorted it number 30 £12 from vw

[Supercharged 2]

Set the CO pot to 550Ohms

 

As above the original problem is most likely the ECU relay - number 30 which is now superseded by 32

 

(If yours is 30 then it's most likely to be original!)

[Yandards 0]

It's not the ECU relay.

 

Relay failure is characterised by a sticking contact within the relay preventing any power from being transfered/made available to the required circuit.

 

The ECU relay within the G60 setup powers the ECU which in turn provides a power signal to the fuel pump, if the ECU relay was failing you would not get the fuel pump to run and the engine would also cease to run as the injector open command comes from the ECU.

 

Poor running at idle when trying to set the CO(0.7% Vol + or - 0.5%), idle speed(800 rpm + or - 50 rpm) and timing (4-8 degrees BTDC, timing mark on flywheel is at 6 deg and one at 0 deg) is not unusual.

 

I would check the following:

 

Earth points, gearbox to chassis earth, battery negative to chassis earth, coil lead to cylinder head - all of those tend to gunk up overtime and digi requires a good earth to function well.

Vaccum hoses from TB to ECU and carbon canister - the one to the ECU needs to be exactly 1 meter in length and of the correct VW made hose, try swapping the 2 vac hoses over on the TB as these when fitted around the wrong way can cause some of the symptoms you describe.

Next move onto the timing, the BTS will need to be unplugged to put the ECU into timing mode, you also need to rev the engine 3 times above 2500 rpm to activate this mode. You are looking for around 6 deg BTDC at 2250 rpm - the full range is 4-8 BTDC at 2000-2500 rpm.

I would then tweak the idle down/up to 800 rpm.

Finally try to get the CO to 0.7% by volume, you will need a gas annalyser to do this so your best bet is a decent local garage with the correct kit.

 

All the other sensors (coolant temp, air temp, lambda etc) are all there to adjust the fuelling for efficiency and smooth running, so whilst they do have an input (notably coolant temp on cold start) the car will still function. Do not under any circumstances add extra earth wires to the sensors - it messes with the signals into the ECU and makes the car overfuel.

Have a search on the internet for G60 self study guide, it will be in a PDF format and contains a lot of good information about how the various sensors work and what effect they have on the car.

[Supercharged 2]

It's not the ECU relay.

 

Relay failure is characterised by a sticking contact within the relay preventing any power from being transfered/made available to the required circuit.

 

The ECU relay within the G60 setup powers the ECU which in turn provides a power signal to the fuel pump, if the ECU relay was failing you would not get the fuel pump to run and the engine would also cease to run as the injector open command comes from the ECU.

 

 

 

 

That's exactly the problem you get with an intermittent ECU relay - loads of us have had the same running symptoms caused by a failing ECU relay!

[Richardshoes 0]

http://pdfcast.org/pdf/vw-self-study-programme-103-1-8-ltr-engine-with-g-supercharger-construction-and-operation