Sun 8 Mar 2009 19:49 98 2.0 Petrol only runing on 3 cylinders - jeffhoofe

Hi can any one help iv got a s reg 406 2Lt petrol Lx which has just started to misfire. iv replased spark plugs with pug ones and also replased spark pack , thought it may be the injector so replaced it ans still misfireing as if only runing on 3 cylinders can any one help jeff. Edited by Dynamic Dave on 08/03/2009 at 20:51 Reply | Report as offensive | Link

Sun 8 Mar 2009 22:29 98 2.0 Petrol only runing on 3 cylinders - boggles

If this has the large coil pack, which pushes onto all four plugs at once. A common misfire cause, is a broken wire at the multi-plug on the main body of it. Reply | Report as offensive | Link

Sun 8 Mar 2009 23:09 98 2.0 Petrol only runing on 3 cylinders - jeffhoofe

i would have to earht the spark plugs i know but do you know what each wire is on that coil pack eg: voltages and function then i can test it with the multi meter Reply | Report as offensive | Link

Mon 9 Mar 2009 12:17 98 2.0 Petrol only runing on 3 cylinders - piston power

Is this electrical fault? Have you done a compression test to see if you have a burnt valve? Reply | Report as offensive | Link

Mon 9 Mar 2009 15:00 98 2.0 Petrol only runing on 3 cylinders - Peter.N.

Take each plug connector off in turn, push a small screwdriver into it, insulated end in hand!, and hold it near something metal on the engine, you should see a spark up to about 1/4" long jump across. You can easliy find which cylinder is missing as taking the plug lead off will make no difference. Could be that the lead is faulty. Reply | Report as offensive | Link

Mon 9 Mar 2009 15:26 98 2.0 Petrol only runing on 3 cylinders - jeffhoofe

there are no plug leads as thay are built in to the spark pack Reply | Report as offensive | Link

Mon 9 Mar 2009 20:15 98 2.0 Petrol only runing on 3 cylinders - steve_earwig

Besides that, it's a good good way of ruining your engine management and giving yourself a heart attack. I think you'd need an oscilloscope to test the coil pack (spark unit) properly. I'm not liking this "as if it's running on three" - either it is or it isn't. You could try pulling the injector electrics one at a time until you find one that's not doing much, the compression test is a good suggestion too. Failing these I'm afraid you'll need to find some professional help. Reply | Report as offensive | Link

Mon 9 Mar 2009 21:38 98 2.0 Petrol only runing on 3 cylinders - Peter.N.

Ah sorry! I havn't run a petrol car for over 20 years. Its not like a Morris minor then? Reply | Report as offensive | Link

Mon 9 Mar 2009 22:08 98 2.0 Petrol only runing on 3 cylinders - steve_earwig

It's similar but "significantly" more voltage, I wouldn't feel comfortable recommending it on a family forum. Reply | Report as offensive | Link

Tue 10 Mar 2009 06:34 98 2.0 Petrol only runing on 3 cylinders - DP

We had the same thing on a friend's 306 XSi (same engine), disconnected each coil pack in turn, and fitted one of the cheap orange plastic HT testers between the coil and the plug (it *just* fits). We could then run the engine completely 'hands off', and with the coil still connected to the plug so no engine management issues. This method found the faulty coil within a few minutes. Reply | Report as offensive | Link

Tue 10 Mar 2009 13:08 98 2.0 Petrol only runing on 3 cylinders - jeffhoofe

its not the spark pack tested on outher car (406) and it works ok , i think it more likly to be an out let valve on number 2 cylinder did comprestion test and its low and im geting a detanation sound from inside the exsurst pipe befor the cat so the fuel must be going out though the valve . Reply | Report as offensive | Link