2-3 cylinders down.Any answers?

[SVR]

Any ideas? HSV started missing and now will only run on 5 and sometimes 6 cyls;
New o2 sensors,comp; ok,plugs new,injectors ok,fuel pump and pressure and flow ok,good spark,EFI shows no trouble codes,but Bank 2 only shows around .1to .15 volts Bank 1 as normal,ie .3 to.9V.Tried different PCM.
Bank 2 fires on 1 not 2 or 3 and occasionally 4.Bank 1 all 4.
Anyone experienced this problem as I am now struggling with it.

[joecar]

Plug wires.
Coil packs.
Subharness to coil packs.

[GMPX]

There is a common 12V between the coils and the Injectors (on a VX anyway, LHS is green wire, RHS is red), perhaps you are losing this, also check the common GND on the coil packs (pin A on the coil pack bulk connector) seems something shared between cylinders on that bank is messing with you.

Good Luck
Ross

[SVR]

Thanks for input guys but still no success.
Swapped coil packs over ,no change,so leads,coil packs and harness ok!
Checked common GND on coil packs A to PCM connections 1 and 40 on both banks.cont: ok.
Checked 12v supply to coil pack and injectors Red and Grn.full 12v supply with ign on. WHERE now i wonder.
As i previously said every mechanical aspect fully checked out.It must be electrical, but where :?:

[GMPX]

What state are you in?.

Cheers,
Ross

[SVR]

United Kingdom

[Delco]

You need to narow it down to if its spark not firing on those cylinders and injector not working on those cylinders then follow through depending on what you find.

[SVR]

I must be missing something really obvious because all plugs fire,each one seen to spark,and each injector energises,ie,with lovolt test lamp and tech 2 shows each working.EFI also confirms,so with no mechanical problems!!!! do not know where to look now.

[GMPX]

United Kingdom

Ah, I forgot that HSV's were sold in the UK.
I was going to recommend someone in Aus but that's not good.
Anyway, I really have no other suggestions, something like that fault I'd need to be at the car with a scope, that's about as far as I could go.

Cheers,
Ross

[tuff]

You said that the injectors are firing are you sure there not clogged?How many miles on the car and what kind of mods have you done.On those cylinders that are not working are the plugs the same color as the rest?When you drive the car do you feel the cyl missing Or does it happen only under a load.