m42 missing

[falo91]

hi there having some problems with my m42 like rough idle and missing under load ive only just fitted the engine to my car originally was an m40 now swaped to m42 i done all the gaskets prior to fitting the engine like headgasket and all the inlet gaskets and replaced all the pipes around the inlet area as most were cracked so im pretty sure its not an air leak also swaped spark plugs and leads but made no difference could it be the cam sensor?

im asking this as when i disconnect the cam sensor it makes no difference at all to the running of the engine

cheers Olaf

[jimbom30cab]

Are you absolutely sure the ht leads are plugged into the right coil pack connections

[falo91]

yeah ive checked and double checked also replaced the blue temp sensor and checked the the readings at the ecu plug all is fine there the buggers driving me insaine

[martijn76]

Don't you have punctuation marks on your keyboard?

Are you sure the timing is set correctly, after changing the headgasket? First check that, if that's not the problem then change the ingition coils for some new ones or a confirmed good working set. 9/10 times they are the source of a bad running m42.

[falo91]

nah dont use them and timing is spot on i locked it all while doing headgasket and checked coils all firing perfect

[age]

Do you have a chip fitted?
Is it possible you bent a valve?

[falo91]

not sure about a chip i didnt fit one ill have a nosey in the ecu. valves im pretty sure are fine the miss isnt always there if you rev it up and down a thew times it goes away for a moment then when you let it back down to idle its missing again

[falo91]

rite ive checked the ecu its never been opened so its not chipped ive now adjusted the afm and it cleared it up a fair bit its not really a miss anymore its more hesitating now once its passed 4000 it goes then any surggestions to that ????

[Connar]

Mine seems to do this.... Only when really hot (driven over 20/30 miles). Car is completely standard engine wise, just looses a lot of power and a mechanical limiter happens at like 4000rpm odd. Only thing I can seem to point too is either the leads being knackered or one of the ignition coil packs have had it. Cleaned the crank sensor still seems to magnetise and the car won't even run without it so I can't imagine it's that. Going to get leads and go from there!

[mcspike]

I'd change all the ignition coils and leads, Connar.