As per title,

Newly started Megasquirt installation, is running on cylinders1,2,&3. 4 is cold, the exhaust hasn't blued up during running.

I've swapped injectors and plugs about with no joy, removed the plug and lead and ran the Edis in limp home mode got a spark from the plug, when looking inside the cylinder the top of the piston is wet.

I've yet to source a compression tester, but the problem is starting to annoy.

Suspect coil pack and megasquirt i feel have been ruled out as they would show up as a pair of faults, or i'm talking out of my hoop again.

ATB Dan.

Have you checked the plug leads dan, i had the same on No 4 when i got my megajolt up and running and it turned out to be a failing HT lead.

Ive had the same with faulty plugs.

Standard practice is to swap the leads and see if the problem stay on the same cylinder, if it does then swap the plugs, jst keep swapping stuff as far as possible until the problem moves with the swap.

Nuisance to have to start on the injectors, hopefully it will be solved before that

John

My daughters fiesta Zetec S had the same problem. Not firing on No 4 cylinder.

Turned out to be coil pack fault. Fired ok on 1,2,3 but not 4.

Replaced coil pack & has run OK since.

Hope this helps

Another vote for HT leads. Coil pack would mean only two cylinders on the Zetec-E

Another vote for coil pack. coil output on 4 is shorted to ground.
Swap 4 and the corresponding coil output, see if 4 gets hot. Or check the resistance betwwen ht output and ground (earth) If less than 1Mohm (1000000 ohms) then coil pack is faulty.
Darren

The last one I did was the leads but have had a couple of faulty coils.

Looks like a set of leads, we've tried 2 other coils, mind one was change when we were trying to start it, the other one was from the fleebay!

Pity the orginal plug and lead worked in limp home mode, would this be any different when the plug is in the head?

ATB Dan.

plugs fire very easily when in open air but have a much more difficut job doing so when under the effects of cylinder pressures and combustion

Plugs for me. Mine was running lumpy with number 3 off and a new set as a starting point cured it.

Don't buy cheap leads either, puka Ford ones are needed for a good reliable engine.

10 points and a blue smartie to all those that said plugs, a new set and she's a runner.

Time to get everything else together so i can do some on-road tuning.

Cheers Dan.