URGENT - firing on 3 cylinders

Incorrectly gapped spark plug..or cracked spark plug...

The message from "David Speir" contains these words:

This is why we don't wash our engine bays, kids!

Take the distributor cap off and wipe inside with a WD40'd cloth. Wipe all over the outside likewise. Treat all the leads the same, inside the sockets and outside as well, and unscrew each plug and give it a good clean and dry.

The plugs are Bosch Super4 plugs which don't need to be gapped and I've just double checked them to make sure they're all in good shape, which they are.

This is normal on a daewoo matiz and some small vauxhalls.

mrcheerful

smarts also... but that's not the point...

Like I said, I've done it before on previous cars without any problems. I've tried everything that you mentioned already but without any luck!

words:

The message from "David Speir" contains these words:

Couldn't you have mentioned that /before/ I typed out an answer?

And, erm, whatdya call those little 1 litre turbo things - Diahatsu Charades.

Peter

BUZZ! WRONG!

All spark plugs need to be gapped. There must be some form of gap so the spark has somewhere to jump from and to. The gap is very criticically defined and either specified in terms of thousands of an inch (known as "thou") or millimetres (eg 0.008mm). What you probably mean is that they are, or should be preset to the right gap. Have you checked the gaps with a feeler gauge (available from any good shop, or a wide selection of crap shops, for about a fiver) ?

I don't know what you mean by "checking they're in good shape" but it doesn't sound like you've properly checked the gaps.

Seventeenthly, take the Super4's out and stick some standard spark plugs (bought from a main dealer) in. They'll probably be cheaper than motor factors and Halfords type places anyway (see the other thread going on). I've read on several occasions about people having problems with Bosch Super4's (and other similar multi-electrode plugs) that have disappeared when they've switched to standard OEM plugs.

Oh,and twentysixthly, you did definitely put the leads back on in the right order didn't you? i.e. carefully removed and replaced them one by one or noted the which ones corresponded to cylinders 1-4 repsectively from the individual sockets on the dizzy cap?? If all else is fine, there could be a chance you've made a mistake and just replaced them in the wrong order. We've all done it. In fact, after servicing my Carlton once I started it up and it was running really rough, then I realised I left an HT lead off :-)

Peter

The message from "AstraVanMan" contains these words:

Teehee! I did that once on an Austin 1100. Took far longer than it should have to work out what it was.

First you need to identify which cylinder is not firing. Do this by removing a plug lead and starting up. If it is much worse, or doesn't start, then that cylinder is OK and was firing. If nothing changes, you have found the dead one. When you find the one that isn't firing, change the plug in that cyl. for one of the others. If the fault changes to the other cyl, there's your problem. If not, try the same thing with the lead.

HTH

Steve

I always half expect the car to not work properly after changing the HT leads. One was a bit loose once and my engine fired on three cyl's, but I knew straight off what was wrong.