LS1 Misfire

[G4orce]

Hey Guys I have had a misfire on my car for a little bit now, I had changed the plugs and leads and still a misfire at idle. I just took it down to the dyno shop and got the engine codes checked (as i had a check engine light on) The only problem they found for a faulty Oil Pressure Sensor. Could this cause the misfire? i don't think it would to my knowledge.

I was very surprised no codes came up for a misfire and now i'm back to square one. Any one got any ideas on what to do now?

[WestieVYLS1]

fuel injectors dirty?

[G4orce]

I did not think of that, maybe I should book it it to get them cleaned. It cant hurt(other then the wallet lol)
Thanks

[burnz]

if its at idle check IAC valve.
if threw the rev range check coils for hairline cracks.

[vt1538]

The holden platform does not use misfire detection like the Yanks, hence no code. First thing I would do is run the engine in the dark & see if you can see spark jumping due to bad leads, cracked plugs etc.
If that doesnt help, try & isolate which cylinder the miss is in by one at a time removing the injector plugs with the engine running. Once isolated swap leads with another cylinder & see if the miss follows the cylinder or stays in the same place. If it stays in the same cylinder check that plug. Next step is to swap the coil packs from bank to bank & verify if the miss is still in the same cylinder or swapped banks indicating the coil or wiring is US.
If the miss is still present lift the rocker covers & inspect the rockers, valve springs etc. Last step would be the injectors.
This could all be done quite quickly with something like Efilive as you can cut cylinders with the scan tool to save messing with the injector harness. I am surprised the shop didnt do this for you as it would only take about 10 minutes to go through the whole procedure.

[G4orce]

Thanks guys i have a few more ideas now and will get onto it tomorrow on my day and let you know how I go.
Thanks again

[doobs]

The holden platform does not use misfire detection like the Yanks, hence no code. First thing I would do is run the engine in the dark & see if you can see spark jumping due to bad leads, cracked plugs etc.
If that doesnt help, try & isolate which cylinder the miss is in by one at a time removing the injector plugs with the engine running. Once isolated swap leads with another cylinder & see if the miss follows the cylinder or stays in the same place. If it stays in the same cylinder check that plug. Next step is to swap the coil packs from bank to bank & verify if the miss is still in the same cylinder or swapped banks indicating the coil or wiring is US.
If the miss is still present lift the rocker covers & inspect the rockers, valve springs etc. Last step would be the injectors.
This could all be done quite quickly with something like Efilive as you can cut cylinders with the scan tool to save messing with the injector harness. I am surprised the shop didnt do this for you as it would only take about 10 minutes to go through the whole procedure.

Would pulling the injector plugs like that cause the engine light to come on?

[vt1538]

Would pulling the injector plugs like that cause the engine light to come on?

I dont think so. I use my scantool to isolate the cylinders so I havent tried the low tech method.

[doobs]

I dont think so. I use my scantool to isolate the cylinders so I havent tried the low tech method.

No engine light when pulling the injector plugs off, im supprised how 'smooth' the engine runs on 7 cylinders, but previous to my V8 ive only had T6's and 4s