Hard starting/low idle/slugging at low revs

Australian

I've got a zafira a z22se hard starting - seems to be overfueling as wot will get it to come on when it fails the first time, with a bunch of fuel smell. But this could just be due to the fuel getting injected in to the cylinders when it fails to start.

Also quite weak down low, and idling down at about ₆₈₀ - occasionally will shudder as if to stall but IACV seems to pick it back up.

Doesn't sound like it's missing though? Starting issue not dependent on hot or cold. Have changed spark plugs, no eml - any common causes? Would expect some kind of code if the coilpack was causing it to miss etc.

Have been using an ELM327 to check for faults though, is an opcom going to be able to tell me anything more?

Johnss

Worth to check coil pack.

Australian

Any specific test procedure? Or just pull out the pack, chuck a plug on and see if it zaps a metal surface (the engine head)?

vocky

no eml usually indicates the coilpack is duff, no idea why but it never gives any codes when failing.

evocarlos

vocky said:
no eml usually indicates the coilpack is duff, no idea why but it never gives any codes when failing.

the coils have no connection to the ecu for diag and knock is done thru the external sensor only cam signal malfunction is reported to the ecu

Australian said:
Any specific test procedure? Or just pull out the pack, chuck a plug on and see if it zaps a metal surface (the engine head)?

remove the coil pack then unscrew the icm (silver unit) use a multimeter on interconnect on the coils pack and check the resistance if close to 0.4ohms for both coils a 0 reading means it has a dead coil you can also test the icm transistors with a test lamp by cranking the engine looking for the flash on the output

Johnss

evocarlos said:
the coils have no connection to the ecu for diag

Hey Carl, do You know does Z22YH coil have connection to the ecu for diag?

evocarlos

no just the triggers to make the 4 coils fire

Johnss

All right, thanks mate.