Lumpy G60 No.2

[sharlie1982 0]

Hi all,

 

I have recently started to notice that my 92(K) G60 has developed a misfire :x

 

It seems to miss occationally at idle (especially when cold).

 

The worst problem is when I boot it.

 

As soon as the boost gauge gets to around 0.5bar it misfires quite badly, and thus makes the car hit a wall so to speak.

 

It seems alot worse when I run the car on normal (premium) unleaded, Optimax seems alot better.

 

I have recently run out of petrol and was wondering if the injectors needed un blocking?

 

Any ideas?

 

Lee

[GazzaG60 0]

check

plugs and leads, dizzy cap. plug gap.

fuel pump and filter. filter poor/old

knock sensor. fucked torque?

fueling in general. (co-pot) rich

o2 sensor.

ignition timing maybe to advanced.

isv.

 

i have issues with fueling where a bad o2 circuit would make it miss when going WOT or to the map

 

co-pot issues similar. when i went chip and pulley all the broken bits get amplified and come out of the woodwork. whats the co-pot ohm setting. what s the a/f at idle and on boost and going onto boost.

[sharlie1982 0]

How do I check these values. Is it done via the MFA check procedure?

[GazzaG60 0]

take a plug out straightr after a run. try not to idle it too long. look at its colour or take a picture and post it. if they are black its rich. if they are white lean and spots of white or damage are det marks.

 

change the fuel filter. its under the car just near the drivers rear wheel. bout 5 quid

 

knock sensor is on front of engnie. its a round black thing with a wire on it to the left of the oil filter housing . if the wires looking bad replace it. torque to 10 lbsft i think. you can run the engine and tap it with a spanner and you should hear the engine change. this is timing being pulled.

 

the co-pot is on the boost tube gonig to the throttle body. its a sensor with wiring coming of it and a white cap on one end. put a meter across the 2 edge pins. take a reading of the ohm. post it.

 

02 sensor should produce v between 0-1 on the signal wire. its purple coming from the 02 sensor harness. it should fluctuate when warm. this holds good fueling at idle and cruise. an af gauge is a good idea as it can help with this and other issues

 

proper wideband af needs a meter to measure. of boost you should see 14.5:1 or so. and on boost around 12:1

 

start with the cheap stuff or get it serviced by a reputable company who will set it up properly. gwerks are popular on here. darren seems a good bloke

[G60Dan 0]

Your problem sounds different to mine. Mines fine under load. I was getting it just as idle, mainly when cold.

 

I think mine was a vacuum leak from the throttle body to the ecu. Will confirm when it back on the road.

[GazzaG60 0]

the vac line needs to be 1m exactly and use the proper vw tubing.

[h100vw 0]

How old are the plug leads? Do they have the tin shields on them at the plug end. I have had a couple of cars miss in the past because those shields were helping to cause a short. I fixed a big miss on pickard1s G60 the other week by removing them.

 

Is the exhaust really black? That could be overfuelling.

I'd definately look at the output of the Lambda probe with a voltmeter. It will be a steady voltage climbing to 1 volt if you look with the engine stone cold.

 

Once up to temp, the meter won't get a steady reading as the sample rate will be too low. It will appear to fluctuate between about .5 and a volt. The changes will be repeating pretty constantly. If you floor the throttle briefly the output will hold at a volt(rich) then drop to nothing(fuel cut off on the over-run) as the engines slows down. It'll start to cycle again once you get to 1500 revs. This is the fuel coming back in again.

 

I don't feel the octane rating of the fuel is the problem.

 

If it is running rich it could maybe be the blue temp sensor.

 

Gavin