V6 Misfire

[Paul B]

Hi

 

I have a 2002 2.8 V6 Galaxy. I have had it for about 5 years, more or less problem free. It has done 73K and I have noticed that it is misfiring occasionally.

 

I have put it onto Vag-com, but nothing appears as a fault code. So last weekend I changed the plugs, which were a year old and replaced the Air Filter, as routine servicing, in the hope this would improve things.

 

However, it has not. The Coil packs are about 2 years old and have covered 16K approx. I had these replaced when I had the LPG Conversion fitted, and it has run fine ever since. I suspect that one of the Coil Packs is faulty, so have ordered one to try and see if it makes any difference.

 

I'm just looking for ideas really. Has anybody else had a similar problem and managed to cure it?

 

I first noticed that the idle was getting worse on both petrol and gas. Most of the time it runs on 6 cylinders and because it is so intermittent it is not illuminating the Engine Management light, like it would if a Coil Pack went completely. When it is idling roughly, I hear a relay click in the fusebox, then it idles badly for about 5 seconds, before returning to all 6 and idling normally. It doesn't always do it, but it is getting more frequent. As soon as I hear the relay click, I know it's about to idle roughly. I'm not sure if something is compensating for a dodgy coil pack which may be causing it to misfire so intermittently, hence the relay click?

 

Also, when revving the engine around the 1300 rpm, it is quite juddery and is quite noticable when driving. You can distinctly hear it missing if you stand behind the car, by listening to the exhaust. It seems to miss throughout the RPM range, but intermittently. Noticably worse though in the lower range. I thought it was the front bushes to start with, until I noticed the engine juddering whilst I revved it without it being under load.

 

Any suggestions?

 

Thanks.

 

Paul

[DaveM]

Just got my '98 V6 back from the garage today for an intermittant misfire.

it wasn't so much a misfire, but struggling to tick over, (rpm all over the place) and flat spots when cruising. (under acceleration it was OK)

Some days it was perfectly OK, but then other days it was a nightmare.

it to would 'click' then struggle to tick over

 

it appears mine was a dodgy MAF sensor.

 

but then the intermittant MAF fault appeared on VAG-COM as just that. (MAF sensor fault - intermittant)

 

worth a look though

[Paul B]

Just got my '98 V6 back from the garage today for an intermittant misfire.

it wasn't so much a misfire, but struggling to tick over, (rpm all over the place) and flat spots when cruising. (under acceleration it was OK)

Some days it was perfectly OK, but then other days it was a nightmare.

it to would 'click' then struggle to tick over

 

it appears mine was a dodgy MAF sensor.

 

but then the intermittant MAF fault appeared on VAG-COM as just that. (MAF sensor fault - intermittant)

 

worth a look though

 

 

Thanks Dave. I think after the Coil Pack, I will head there next, Lamdba Sensor too. I feel it is on the ignition circuit somewhere, but I may be wrong. It may even be more than one Coil Pack, but I thought at least if I tried one, which I can move across all six cylinders a bit at a time, I would be able to either cure it or eliminate them as being the fault. Awaiting delivery of Coil Pack. Hoped it would be here today, but it's not.

 

MAF Sensor is my next thought.

 

Thanks. Will keep you posted.

 

Paul

[mikej]

Hi mate i run LPG also although be it on a 2.3 and have been trying to find the cause of a misfire for a few weeks now turned out to be a duff lead , original ford equipment and less than 2 year old :P managed to locate the arcing by going out in the dark , no street lights etc bonnet up and a blanket over my head . Looked bloody stupid but found it straight away which was all that mattered ! i totally dismissed the leads as they were not that old , possibly worth a look?

[tpurch]

I had a similar problem with a MK1 Sharan, it turned out to be a bad connection to the MAF sensor. After unplugging it and plugging in back in a couple of times engine ran like a dream.....there were no reports of a fault with VAG Edited March 18, 2009 by tp1_1uk

[MrT]

When my coil pack started playing up I had engine misfire faults recorded which I read by VAG-COM. There were a load of faulty coil packs around the time yours was made but the replacements should be fine. One thing to check is the wiring harness to the coil pack, garages have a habit of damaging the retaining lugs on the plug when the forcibly remove the plug from the coil pack.

 

As to the MAF, I bought a cheap aftermarket MAF and it caused nothing but problems, buy a discounted BOSCH and not a BOSCH equivalent. (Some aftermarkets even have the BOSCH part number moulded onto them).

[Paul B]

Hi

 

Now for an update! I picked up the new Coil Pack today and have gradually swapped across all 6 cylinders, in the hope that it would fix it. Nothing!! No difference whatsoever. So either it isn't a Coil Pack, or it's in the wiring going to one of the Connecting Plugs to the Coil Packs. My feeling now is that it probably isn't a Coil Pack at all.

 

Lambda Sensor perhaps? If I unplug that, I should find out I think. If it runs better, I'll have found it. Are there many problems on MAF Sensors on Petrols, I know the Diesels suffer. If so, surely it would show a fault code?

 

Any ideas? No Fault Code showing, intermittent idle problem and rough running (appears to be missing) 1300rpm upwards. It's driving me mad! I'm even wondering if it's in the Engine itself now, perhaps I need to do a Compression Test, but I don't think these engines normally give up at this mileage?

 

Any suggestions welcomed, apart from put a match to it!

 

Thanks.

 

Paul

[Paul B]

Today's update!

 

I disconnected the Lamdba Sensor to see if the car ran any better, it made absolutely no difference to my problem.

 

So far I have:

 

Replaced the Plugs

Replaced the Air Filter

Replaced a Coil Pack (moving it across all 6 in the hope of finding a dead one)

Disconnected the MAF Sensor - Car ran no different

Disconnected the Lambda Sensor - Car ran no different.

 

It is still quite juddery and appears to misfire. Very occasionally it idles rough too, but when it does, I hear a relay click somewhere in the fuse box, 5 seconds later it's normal again. I'm not sure if this is connected, as it appears to be running on 5.5 cylinders a lot of the time, but not all of the time.

 

I'm wondering whether it is still the MAF Sensor, the ECU or a burned out Exhaust Valve in the Cylinder Head (last resort). I don't understand why no fault code comes up. I have the basic version of VAGCOM, if I upgraded to the licenced full version, would this give me access to more fault codes? I presume that I should already be able to see all fault codes with my version, but just have less access to other areas on the car?

 

I would really appreciate any ideas or comments. I love the car and don't want to scrap it just yet, but it's crossing my mind now.

Edited March 21, 2009 by Paul B

[DaveM]

My replacement MAF seems to have done the trick.

it hasn't missd a beat for a week now. (fingers crossed)

 

I too thought it could be a burnt out exhaust valve, aarrgghh! it certainly felt like it, but thankfully not.

 

One more thing, my Ford 2.8V6 would struggle to talk to VAG-COM. (on the odd occasion it did it only reported a couple of faults), my mate then tried to connect as a VW Sharan and it it connected straight away and displayed a long list of fault codes! (minor ones or MAF related)

 

I guess my Galaxy Ghia X is a VW in disguise. (it also has a single coil pack 'brick' which I gather is a VW thing also)

 

good luck

[mk2vr6]

I guess my Galaxy Ghia X is a VW in disguise. (it also has a single coil pack 'brick' which I gather is a VW thing also)

 

good luck

 

all VR6'S are VW's Ford couldnt make an engine that sweet :angry2:

Edited March 24, 2009 by mk2vr6