Tb42e

[Pezzer]

Hi all , just had a firing issue which turned out to be the ECU getting hot from a wiring problem, that sorted now it has pulse and spark whilst trying to fire. Now it seems to pressurize the inlet manifold hence not allowing the ignition to happen, have had it suggested a stuck valve, but I was running the car only days before. Can this be sorted by removing the rocker cover backing off the tappet and using a plastic hammer to free the valve, or is it head off.
Thanks for any input...

[GQ TANK]

I would pull the rocker cover off and crank the motor. Watch the valves - you should see if any of them are stuck as it wont move.

But - it could also be a tappet out of adjustment, lobe gone on your cam etc - this fault condition does not sound correct.

If a valve was stuck than I would assume the head is stuffed and ossably other damage

[billyj]

are you sure that the ignition timing is set right? if its firing too early it could be firing back into the manifold creating the pressure your noticing, i doubt just a bad seal when cranking would do it as it would just pump into whichever cylinder has its inlet valve open. id check the timing and if that doesnt help compression test it, a low reading that doesnt improve when you add a small squirt of oil indicates bad valve or similar.

[Pezzer]

Turned out Lube mobile on the Saturday callout put the timing 180 degrees out and eventually causing such a big backfire it took the complete back wall and all the pipe to the tip clean off my new muffler. At least 5 times I questioned the timing and was told it was spot on, never again......

[billyj]

and now ill mention that you need to disconnect the aac valve(puts ecu into base/diagnostic mode) to set the timing otherwise it will be approx 5deg retarded from where it should be