kusee pee

My Carrera 3.2 has picked up a strange misfire/stutter at low revs and idle. It came on yesterday and has remained this morning. I've checked the plugs/distributor and squirted some WD40 around in case water had got into the sparking system somewhere but to no avail. I can't see anything loose around the air intake and I had the air-flow meter looked at a few months ago and all was fine. At higher revs the misfire goes and it pulls strongly.

One strange thing - when poking around I noticed what looked like a white gunge at the top of the oil filler, under the cap. Like there had somehow been some water ingress in there? I jetwashed the car last weekend and then topped it up with oil straightafter. Is there some way that water could have got into the engine?! And would this explain the misfire? If so, what should I do? Just drive it til it burns out?

Any suggestions much appreciated before I go down the expense of taking it to the shop...TIA.

theiceman

well moisture under the cap and in the return hose from the tank to the intake is not all that unusual , certainly not desirebale by any means but not disasterous either.
I wouuld strt out by replacing the cap and rotor and plugs simply because they are maintananace items anyway and water is nnot good for any of these.

Then I would check the coil connections very carfully and see what happens from there.

MDL

Ditto to what Ice says. I had a very similar problem with my 3.2, I think all of them do at one time or another. Mine started running rougher and rougher slowley over the coarse fo a few months. I changed all the plugs, wires, cap and rotor and still had the same symptoms. What finally cured it was removing the injectors, cleaning with BG injector cleaner and reinstalling them. You'll need to get new O rings for the injectors which are cheap. It's really very easy to do. The problem was cured instantly. Not saying that is your problem but mine ran very rough until I cleaned the injectors. I noticed my wife's 06 Honda was doing the same thing only not as bad. We both were using Sunoco gas which I thought was good fuel, and may be in other locations. I switched both cars to Chevron and they both run much better. Not saying you have to run Chevron, just search for the best quality fuel in your area.

BTW, the first thing I would do is COMPLETELY remove any WD 40 that came in contact with your car. Then take can, throw in garbage.

Ed Hughes

Spraying some starter fluid around the intake gaskets/boots will tell you if you have any leaks there-the R's will rise.

But, I'm wondering if your oil cap had a good seal? I'm sure you've noticed how the R's drop when you remove your oil cap to check the oil, and open the system. But, then again, I don't think this would cause a miss at low revs, just a lower idle.

rusnak

You have gotten all good advice in this thread, except you can save the WD-40 for things like gate hinges and house keys. The issue is residue, and you don't want it on your ignition contacts in my opinion because that stuff will burn.

Using a pressure washer on the topside of your engine is a bad idea because of the things that can get damaged by water and pressure. You might have a short somewhere, or you could have forced the vacuum control for the fuel pressure regulator off, which would make the car run rich.

You can try running the car at night in the dark. Take a look without a flashlight for arcs and grounding. If you see any kind of lightshow, then you have bad spark plug wires.

I hope you didn't add too much oil.

kusee pee

Cheers guys, I've done all the checks that are within my very basic skill-range and it's going off to the shop next week. Hopefully it'll be something straightforward.

Interesting to hear the anti-WD40 views - it was my mechanic who suggested it to me but I'll be keeping it in the drawer from now on!

der Mond

I had strange misfires and tach anomalies and finally loosened and cleaned and re-tightened all the ground points I could get to, referring to the Bentley ground point map, including the one where the Motronic-related wires ground to the left side of the intake manifold runner. Can't hurt even if it doesn't help. Cured my problem.