Me and a mate of mine have just replaced a head gasket on a Mondeo 2.0 litre Zetec engine.

Everything has been put back together correctly and torqued up properly but there still appears to be a problem with the spark from 2 of the plugs.

We've replaced the spark plugs, ignition leads and the coil pack and we've checked that all electrical plugs are plugged in correctly but the problem still persists.

Basically, it's not running properly and it's very difficult to get started. On further investigation, we found out there is a weak spark on plug 3 and plug 4 appears weaker still.




Anyone got any ideas what it may be???


All help much appreciated

 

Someone must have an idea???


Please

 

check the wiring for the coil pack has not melted on the egr pipe just below the coil bracket also the metal on the terminals sometimes opens up gving a poor connection (three pin connector on coil)also just make sure nothing trapped when head refitted or dowel in head not holding head up might be worth checking compression (poss burnt out valve?)

 

Did you change the coil pack for a known working one? Theres a common fault on the one plug, number 3 IIRC, if not its number 4......very coincidental....

 

That's strange!!

Plug 3 and plug 4 are connected to seperate coils! Plugs 1 and 4 are fired by the same coil so if 4 has a very weak spark, then 1 should be equally as weak! As with 2 and 3.

If you had said that it's not firing on 1 and 4 together, or 2 and 3 together, then it would be more logical that the coil pack or the wiring to trigger it was U/S.

 

Coil pack that we fitted is defiantely fine. Used to be on my old XR2i 1.8 16v. All wiring is fine as we checked that already.

I'll see about getting it pressure tested next then

 

Sounds silly but have you checked the plugs/leads?

 

Are the plugs and leads new? If not, then I wouldn't do much more without replacing them.

The Zetec leads are prone to breaking if disturbed.