misfire on peugeot campervan

[The Natural Philosopher]

Ok, I thought I'd run this one past ou all..

Yes its my bloody camper, wot I write about last year as having crap fuel consuimption..well its always sounded odd when cold, but in the current cold weather it got much worse, to the point where it became obvious it was actually only firing on three cylinders..and the occasional massive BOOM from the exhaust and a stink of raw petrol confirmed that unburnt fuel was collecting in there.

Ive got a set of new plugs for it, but I pulled one out today and there was no sign of excessive wear or age..this camper was bought second hand a year and a half ago, and its always been a bit juicy and gutless..

So I will try those tomorrow, but my deep paranoid suspicion is that there is more to it than that. I would have aid 'coil' but these things aren't that simple are they?

Anyone know their way round these?

It's a Boxer chassis with a 2 litre injected petrol. About 97/98 vintage.

Am I right in saying that plugs, leads and something called a 'coil pack' are the main elements of the ignition.. One of those components is breaking down under high voltages..intermittently. By dint of using high RPM and getting the battery voltage way up, after a couple of hours I did manage to get it into 5th gear and over 60mph..the usual stuff..light throttle high RPM is good..pulling from low on a rich mixture it misfires totally on one, and at moderate revs in low gears, I could feel the 4th cylinder coming in and going out as it juddered..

Anyway, any feedback, or humorous stories welcome.

[Matty F]

Why not replace the plugs one at a time and test the engine each time. Label where the plugs came from. I'd say the most likely answer is one plug that seldom fires.

[meow2222]

And as I said thats a wrong assumption. I know this from experience. Compression problems can produce precisely the symptoms you describe. So can a borderline mixture. FWIW your description of driving performance doesnt tally with a vehicle running healthily on 3 cylinders but the 4th one down, it sounds much worse. Again this is from experience. But I'll leave you with your assumptions.

NT

[The Natural Philosopher]

On a 20k mile engine? unlikely.

No, that's subtly different. Ignition tends to be totally 'on/off'. Mixtures give you flat spots..and besides, rich mixtures run, but smoke. I wasn't smoking. And bad injectors don't leave raw fuel pissing out the exhaust. I had fuel for sure, but no spark. And it wasn't water in the cylinder, cost that gives white smoke.

FWIW your description of driving

Then you are an ass. Ive driven cars on 3 cylinders and I know what it sounds like. It was occasionally firing, but mostly it wasn't.

Again this is

Well *my* experience has proved exactly right. When I got round to changing the plugs two were fine. One was suspiciously rusty around the base, and the 4th had 3/4" of water in the cylinder head recess all round the plug. Prevented from evaporating by the plastic sealer ring that is supposed to stop water getting in..sigh.

Now I think about it, I did drive through a flood on the way back from the last long trip..

Anyway she's chuffing along as per normal now.