G60 lumpy/misfire, but ok when cold!

[Andy T 0]

The G60 started getting lumpy and a little jerky on accel/deccel this morning in heavy rain, but was ok for first ten minutes.

 

Driving home tonight in the dry was ok for first ten minutes (motorway), then same happens again!

 

When I got home I noticed the exhaust was a little black but no black smoke when idling or driving.

 

I unplugged the blue temp sender (revs dropped a little) which seemed to sort the problem out, plugged it back in again and it still ran ok, then I increased the revs slowly and everything was nice and smooth, until 4k, when it started spluttering/misfiring and the revs decreased to 3.5k even though i'd held the throttle in the same place!

 

It then idled roughly as before. Went through the same procedure again and it was exactly the same each time -

 

Unplugging/re-plugging blue sender cures it, but revving over 4k brings back the lumpiness!

 

The ECU-TB hose & Lambda probe were replaced last summer (genuine parts) with new lambda earth lead/wiring checked etc. Just replaced dist. cap & rotor, although the plug leads are the originals.

 

Anybody any clues? I'll replace the blue temp sender but I got a feeling it won't be that easy!

 

Thanks for any help,

[carpoid 0]

Have a read of Supercharged's thread in 'Engine Bay' - VERY LUMPY G60 mate. Simular probs that i'm having aswell. The thread doesn't amount to any solution but might give you some clues !!

[Andy T 0]

Ran the car yesterday with the lambda probe unplugged and the car ran fine..

 

connected it back up this morning and it was back to rough running after 10 minutes driving

 

So am I looking at a newish but faulty lambda probe, faulty wiring, or could it still be to do with the blue temp sender?

 

When the lambda is disconnected, are there any other sensors that are ignored, i.e. blue temp sender?

 

Cheers

[Supercharged 2]

Check the earth to the lambda (nut next to the plug near the rear engine mount)

 

Still got probs with mine, still not sure what the problem is but learning loads!

[kongo127 0]

Have you inspected those micro-switches on the throttle body, and their connector?

Give them a good WD40 clean... 8)

Well... I would do that! :?

If it doesn´t work, i will start to suspect on the lambda probe.

Keep posting! :)

[Andy T 0]

Cheers guys... The lambda earth is ok I cleaned it up last time and also ran new earth wire from that point up to the earthing point on the o/s strut tower.

 

I haven't checked those microswitches though, might also try fitting temporary extra battery-engine/gearbox earth cable to see if that makes any difference

[Supercharged 2]

might also try fitting temporary extra battery-engine/gearbox earth cable to see if that makes any difference

 

Easiest way to test this is to use a jump lead...

[Andy T 0]

might also try fitting temporary extra battery-engine/gearbox earth cable to see if that makes any difference

 

Easiest way to test this is to use a jump lead...

 

 

Never thought of that, thanks!

[Garry 0]

Did you ever get the 'lumpy' running problem sorted?

 

Mine has developed exactly the same symptoms!

[Andy T 0]

Still got the problem, running ok with probe disconnected, not had the time to do some proper investigation yet

[h100vw 0]

Whizz over to warrington meeting and I'll have a look for you. I'll be there around 2-2.15.

I can bring a voltmeter.

 

07766 702997

Gavin

[potatonet 0]

dunno if my problem is the same, its falters to start and start running correctly on first try? check ure timing, if it was the same problem as I just had, your toothed timing crank gear's key could be going. cost me around 1000 US to figure it out too. yes it does die in power randomly and then comes back or sometimes wont come back till next time you start.

[potatonet 0]

also check fuel filter and the ground for the ECU.... does miracles.

[Garry 0]

I have pretty much checked everything except the Lambda probe - gonna fit a new one this weekend.

 

I have a feeling that mine has been baked in oil as a result of the supercharger seal giving up on the motorway.

 

Have just finished completly rebuilding the block and the charger.

[Garry 0]

New lambda probe now fitted - seems to have cured the problem :D

 

One very healthy G60 :twisted:

[h100vw 0]

Sweet, another one saved from the scrappers :mrgreen:

[Garry 0]

Sweet, another one saved from the scrappers :mrgreen:

 

AMEN

[Andy T 0]

Whizz over to warrington meeting and I'll have a look for you. I'll be there around 2-2.15.

I can bring a voltmeter.

 

07766 702997

Gavin

 

Only just seen your reply! cheers for the offer.

 

Car was running fine for 3 days with lambda probe reconnected, then last night it went back to rough running after about 40 mins driving!

 

Disconnected it again and ran ok. But this morning it was running very lumpy for first ten minutes, so seems I have another problem(or a related one!)

 

it sounded like a very constant misfire from one cylinder, any clues?

 

Going to replace/clean earths, check all wiring and fit new blue temp sender this weekend..

 

does anyone know how many main earth straps are on a g60?

 

cheers

[Henny 0]

2 main earth straps on a G60. One from the thottle body to where the coil mounts to the bulkhead and the MAIN earth from the battery to the gearbox (via the chassis)

 

There's also 3 brown wires which connect to the top bolt of the water flange on the side of the head which are pretty important to the running of the car... 8)

[Andy T 0]

brilliant, I'll get those sorted first then!

 

looks like the main earth strap is crimped straight on to the -ive battery terminal/clamp, do you replace the whole lot or crimp the new one onto the old terminal?

[Henny 0]

The replacement one from VAG comes complete with the battery clamp and the clamp for mounting it to the chassis point too... 8)

 

It's only £25ish too! 8)

[juloesG60 0]

Had similar problem in Feb, felt like running on 3 cylinders for bout 1 week new dizzy cap and rotor, helped then went back to rough. At idle revs fluttered and even when cruising revo would sometimes flutter all over place, also which dosnt seem to have happened to u the car would cut out and not start. After lot of head scratching and two garages, found ECU had 6 solders burnt out! Also was thought to be hall sender so revamped dizzy. A new ECU off Ebay £70 has sorted it. But what caused this seems to have been dodgy wiring by last owner jamming alarm in so got stung by rewiring of fuse box!!!!!!! £1250 total bill. But a few ideas for u there ne way hope dosnt cost u so much!

[Andy T 0]

only just sorted this , a new blue temp sender seems to of sorted the problem!

 

all the lumpiness has gone on cold & warm starts, it runs fine when warmed up and the tailpipe is still nice and clean after a weeks driving!

 

:D