SVR

Any ideas? LS1 started missing and now will only run on 5 and sometimes 6 cyls;Every conceivable mechanical item checked and all ok,ie,Compression,valves,fuel supply volume/pressure,plugs,leads,coil packs,tried different pcm,02 sensors changed,etc,When running Bank 1 shows HO2 reading as normal between 0.3 to 0.9v,BUT Bank 2 which has the missing shows only 0.1 to 0.2v with no oscillation???
Any help on this problem??

SUPRYZE

Check the Injector 2 fuse and see if its blown. It supplies voltage to injectors 2,4,6 & 8 (entire passenger side).

If thats OK, check for vacuum leaks around the intake manifold, you can spray carb cleaner to facilitate. You can listen for a change in RPM, or you can see if the O2 voltage moves off of the .1-.2 volts.

If you don't find anything there, I would take the injectors out and off the rail. Turn them upside down and see if any water or debris comes out of the top of the injector (there is a tiny screen to collect debris and can sometimes hold water). If it looks OK, swap sides with the injectors. If the problem goes to the other side, then you need new inejectors or need them cleaned/flowed.

Also note that exhaust leaks before the O2 sensor will also cause low readings.

SVR

Thanks,Will try your suggestion on injectors and I am certain no vacs leaks.I will also check exhaust and report back on outcome

SVR

Injectors tested and all ok.Exhaust ok.All coil packs ok.
Now at a loss as to where to go next.

WS6FirebirdTA00

iTrader: (33)

what you say tested and you check this stuff, did you use all professional equiptment to test it? or did you just check it out? what about the pushrods?

SVR

All items tested with correct equipment.Also EFI Scan shows STFT and HO2 readings on Bank 2 as max stft(25) with very low voltage of H02 ie .05/.10v only.Denotes very lean but cannot find why these 3 cyls; not getting any fuel.Something amiss on this bank with fuel,I think.Head has been off and all mechanicals perfect.

SUPRYZE

Did you try swapping the injectors from side to side?
How about a Noid light to make sure the computer is pulsing them?
You said you had the head off, did you use new intake gaskets during re-installation?

WS6FirebirdTA00

iTrader: (33)

did you check the maf out? only thing that keeps me from thinking that is you said its only one bank. maybe bad wiring or something. kinda odd. but switching injectors may show something. did you flow test each one on a bench?

SVR

Switched injectors to a proven set.Runs in speed density the C4B engine.All new gaskets/bolts used and done the propane test,which produced nothing.Agree it seems a wiring problem but having gone thro every check that my experience allows me,STUMPED!!!

WS6FirebirdTA00

iTrader: (33)

what is your full list of mods

SVR

Whipple blower/intercooler.Mahle pistons,ARP bolts,roller rockers,water inject,high volume/pressure fuel pump,42lb injectors,baffled sump,hydratrack diff,2.5" exhaust,4 into 1 x1.75" headers,Racelogic traction control,close ratio M6 gearbox,55% uprated clutch,and so it goes on and on.This just a brief description of the mods let alone suspension/brakes,BUT none of this will make the B****r go!!!!!

WS6FirebirdTA00

iTrader: (33)

so it is actually not firing on those cyls? what are all the symptoms

SVR

Getting full spark to each missfiring??? cyl;but even tho power to injectors if you lift off injector cap nothing different happens,It must have lost sequence or something as plugs also do not get saturated in fuel.

SUPRYZE

Have you hooked a noid light to the injector connectors to see if they are being pulsed?

SVR

Yes and OK