VZ 3.6l Engine Miss

[VZS]

VZ 3.6l alloytec had developed a hesitation over the last 6 weeks and recently the "Power Train" alert has appeared on my dash.

Installed 6 new coil packs and spark plugs today.

Engine is now missing, I think on one cylinder.

Checked all the obvious connections.

Power Train alert is still appearing.

What other issue could it be?

[Stewlz]

Fuel injector? Are they new genuine bosch coils and plugs?

[richardpalinkas]

what you can try, if it is missing at idle, go around and disconnect the coil packs from the wiring connections one at a time until one of them you unplug does not change the missing. then you will know it has something to do with that cylinder. swap the coil pack with one from another cylinder and see if it still hesitates on that cylinder. if its still missing, swap out the plugs and check again. if swapping both plug and coil pack to different cylinders and the initial cylinder is still missing, it is more likely injectors. but as you said, you just had plugs and coils done, so more likely one of the plugs has too little or big of a gap

[impulsive]

have you checked all the rubber hoses and plugs for maf, Tb etc?? otherwise go get your fault codes read.. That will determine the exact prob

[trad45]

had the same problem with mine the other day done what u done and started cutting out abit , got it checked out turned out injector number 4 had no power running to it this was caused by my ecu , i got a new ecu programmed it and was all good after then cost me an arm and a leg but had to be done , im just saying it could be ur ecu its a common problem with the vz alloytec

[trad45]

forgot to mention with the above reply o2 sensors could be gone might want to try changing them 1st before any major work like the ecu .

[VZS]

Problem

Engine developed a hesitation when accelerating

Undertook repairs as below and now Engine Missing on cylinder # 4, we think.

Front of engine

1 --- 2
3 --- 4 Cylinder #4
5 --- 6

Diagnostic steps so far
Replaced all 6 coil packs with new
Replaced all 6 sparkplugs with new – Engine missing on one cylinder
Replaced manifold gaskets
Cleaned throttle body around butterfly
Replaced cracked vacuum hose near throttle body
Noticed cylinder #4 plug was wet and not black like other 5 plugs

Swapped cylinder #4 new spark plug for original spark plug, engine still missed
Swapped cylinder #4 new coil pack for original coil pack, engine still missed

Undertook Compression test, all cylinders, 150 PSI

Reinstalled new sparkplug and swapped cylinder 2 plug with cylinder 4 plug, engine still missed
New Fuel filter
New Air filter

Injectors tested Monday 16th Jan 2012 all working fine, didn’t require cleaning, engine still missed

What else is there to try?

[RiCeY]

Try taking it to someone who will actually diagnose it instead of throwing parts at it till it stops faulting for a start.

[VZS]

For those of you playing at home.

New ECU fixed the miss fire today.

We had some fun diagnosing the issues and learning allot more about the VZ engine

Cheers to everyone who helped out

[Sv6 Commodore :)]

i had the same problem with mine for a while, had a service done new spark plugs even got my injector's cleaned. then was told i was using the wrong fuel. I had been using 91 octane, i was meant to be using 97. after swaping fuels and letting it run through the engine for a while the miss has disapeard completly

[Deepo1985]

1-3-5 is the drivers side of the motor and 2-4-6 is the passengers side starting from front to back if Ur referring to a alloytec motor ...