VS v6 chasing a miss on idle

[pete30nz]

Hey guys,

Yes still a miss on idle. The newest thing I'd checked and replaced were the coil packs, no difference.
And that s was after changing out one by one coil pack at a time.

It has finally had a compression test on all cylinders, info in photos below.

Any input much appreciated
Pete

 

[pete30nz]

Last of the cylinder photos

 

[grey_hawk]

Plug #5 looks crap, try a new set.

 

[grey_hawk]

When you posted the plugs firing in your original thread, #5 looked weak there so try new plugs and/or leads.

 

[Immortality]

After a quick look, the best I see is about 155psi, the worst about 145psi. Those results are completely acceptable, One plug is a bit fouled, others not to bad.

Fit a new set of plugs, make sure the plug gaps are correct and then see what happens, monitor plugs/fouling

 

[Grimes]

Fit and gap the plugs like the others are suggesting. If it’s still there after all that, unclip each injector one at a time to work out which cylinder is causing the miss. It’ll be the one that doesn’t make the symptom worse when unclipped.

Once you’ve found it, swap some coils over and see if the problem moves with it. Do the same with a pair of plug leads.

If it stays with the same cylinder despite all that, it’s likely the DFI module or an injector (or injector harness). The little pins are fragile and easily bent so if you’ve had them off before it’s possible you crushed one putting it back on to give an intermittent fault.

 

[pete30nz]

Hey guys,

Plugs arnt done yet, but injectors have been unplugged one at a time. Each injector made the sinario worse, and when plugged back in it settled to where is normally was.

Aiming to get speak plugs.
I have a spare dfi module to check in place, It will be checked this weekend.



I've tried unglugging the iac valve while engine running, and seemed to be ok. I'll leave it unglugged when the cars running today to see if there's any difference today, to rule it out on idle.

Pete

 

[Grimes]

Grab a tin of MAF sensor cleaner and give that a clean up too. If you’re running an oiled air filter it can build up on the wires.

Plugs, DFI are still in play for what you’ve found so far so see how they go with them.

Double check your vacuum lines too.

 

[Immortality]

The OP had another thread with this issue some time ago, I think he's replaced just about everything except the engine IIRC.

 

[Grimes]

Yes, I had a read through it, it’s been quite a saga. I’ll stand corrected but I didn’t see any posts where the plugs actually got replaced, just lots of spark testing.

Coils got done too but I didn’t see confirmation the DFI got done either. Given it’s not isolated to a cylinder it narrows it down a bit, especially when there’s no fault code showing up. He’s got more patience than I would’ve had. By know I’d have had to add blunt force trauma to the possible faults.