20xe running on 3 cylinders - got spark and fuel!

[paul080803]

I have an early astra gte 16v 20xe and it is only running on 3 cylinders (number 4 is at fault). It is idling high and running roughly.

checked the lead and it is sparking, checked with the plug in the lead and that is sparking. Tried a diff plug and lead to be safe and still not firing.

The plug is wet with fuel so that is ok.

did a compression test (cold to warm engine) and 1-3 all read 240ish psi and 4 read 200psi. The reader is old so prob not accurate however shows an imbalance on number 4.

any ideas why it isn't firing on cyl 4? Could it be an injector and the spray pattern is crap?

[Will F]

That's odd, if you have good compression, fuel and spark it should be fine !
Are the plug colors all ok? I'm guessing pot four is black and wet and not lean from an air leak?
could be an injector sticking open? Spray pattern wouldn't cause a misfire try swapping the injector around...

[paul080803]

Will, plug in 4 was black and wet and not lean.

My next plan is to swap injectors with another cylinder to see if the fault moves. Was thinking maybe a loom fault and inj is intimitantly firing?

1 was a little black and wet too, but when you pull that lead whilst engine running it splutters and cuts out. When you pull lead 4 engine doesn't change at all