A conumdrum. A complete bank miss firing!

[RedMist]

Want to make it weirder.... give it a rev and it clears.

Full story. On idle for 5 minutes or so the engine will misfire on one or two cylinders a couple of times then drop the entire north bank very suddenly. Intermittantly it will fire the odd cylinder as there is an odd hot pulse in the exhuast. Blip the throttle a couple of times and it runs on all 6 again.

Ignition is coil on plug and injection is sequential.

FPR reads a constant 3 bar
We have ignition, we tested it with an external plug.
Ignition on number 1 is timed correctly and is 360 degrees from number 4.
Injector timing is correct and matches the PW of other injectors, just phased differently.

Thoughts so far... possible issues with the two TB's being out of balance... however there is a massive balance tube between the two plenums.
Turbo restriction on one bank. But it doesnt explain why we get the intermittant hot pulse.
Cam timing. One of the VVT solinoids being activated... I have no idea if this could cause a bank to misfire. But I'll remove the wiring to the solinoids tomorrow.
FPR issues.... We have crimped each of the two fuel lines to the FPR without correcting the issue. And because they join on a common Y block on the north side of the engine fuel pressure should be common on all parts of the fuel system from the pump to the FPR.
ECU driver issues. We scoped the ecu drives for both injector and ign. Both appeared to be correct when compared to drives for the south bank.

Weird, weird, weird, weird, weird.

[IH8TEC]

i have no idea, but gonna love the weird issues coming up in last few days

[Lloyd]

Its that fancy new multi-capacity system kicking in and turning a bank off to save you fuel



You reckon ignition and injection patterns are still good when it drops the bank?

Just out of curiosity, what are the plugs looking like?

[RedMist]

We scoped injection and ignition at the ECU. Both appear to be normal. We also pulled a coil on number 5 and attached it to an external plug... fires perfectly.
Plugs are iridiums, which are notoriously hard to read. However they look pale to me, lean? They are brand new one step colder than stock.

[1hypo3]

check both cam sensors with an ocilliscope.

Does it have any DTCs?

[RedMist]

Both sensors have been scoped. The 350z engine is the first for Link as such a new trigger set had to be written for it. Its also a bit of a weird trigger so Link had multiple issues getting it to run.

DTC's in a Link?

[Adamal]

Hmmm... You've got iridium plugs, and as they're quite fragile, you probably haven't gapped them.

Try getting some cheap copper ones, gap em and try them out?

[matt dunn]

You will have to somehow get a timing light on the cylinders that it drops to make sure that it doesn't miss-trigger and start firing them on then exhaust stroke,

A 4 gas analyser will mtell you if you have unburnt fuel coming out that side which may tell you if it os a spark of fuel problem,

but like you said,

Weird, weird, weird, weird, weird.

[mjrstar]

is the engine sitting in a similar angle to normal, and does it run factor manifolds.
does it back-fire/ fart before it clears.
My mate had issues with fuel pooling in the inlet manifold which does a lot of weird and wondeful things, in his case when the supercharger started flowing some decent air it cleard it's throat and ran like a dream, but let it idle for a minut or 2 and it turned to a bag of sh it.
it is however an unlikey problem on standard manifold.

[barryogen]

in his case when the supercharger started flowing some decent air it cleard it's throat and ran like a dream, but let it idle for a minut or 2 and it turned to a bag of sh it.
it is however an unlikey problem on standard manifold.

he has got a couple of turbos on it...

[IH8TEC]

no sh1t, it's just an idea for what could be causing it. might be doing something similar.

[Lith]

We have ignition, we tested it with an external plug.
Ignition on number 1 is timed correctly and is 360 degrees from number 4.
Injector timing is correct and matches the PW of other injectors, just phased differently.

Thoughts so far... possible issues with the two TB's being out of balance... however there is a massive balance tube between the two plenums.
Turbo restriction on one bank. But it doesnt explain why we get the intermittant hot pulse.

So it idles fine until its warm, and then goes off on one side only? And which ECU are you running? You are certain its an entire (and the same) bank which is not firing?

Is there any way a lean miss type situation could be happening? Like a valve of some sort (EGR?!) opening and letting more air into one side? Interestingly enough my Skyline develops a slight lean miss (or something) once it has been running for about 5mins and I've never come to the bottom of it.

[method]

Ive had problems with iridiums too. Changed to other plugs and its sweet.

It wouldn't be the plugs starting to foul when idling then clearing up after you rev it??

What RPM does it idle at? Maybe set the idle a little higher.

[YeMs]

i would be leaning toward an ECU fault, or a trigger or igniter fault. considering its knocking a whole bank out.

dont mean to sound dhhuuum but, what engine? what version link?

[barryogen]

nissan vq35, and I believe the latest and greatest link.

[ChaosAD]

Does the ecu do data logging?

Can you do a firmware update? or would that require a retune?

CoilOnPlug setups seem to have problems with heat, so duno if that may be a factor.

Whats a set of ex temp probes and the innovate box worth?

[flygt4]

We have ignition, we tested it with an external plug.
Ignition on number 1 is timed correctly and is 360 degrees from number 4.
Injector timing is correct and matches the PW of other injectors, just phased differently.

Thoughts so far... possible issues with the two TB's being out of balance... however there is a massive balance tube between the two plenums.
Turbo restriction on one bank. But it doesnt explain why we get the intermittant hot pulse.

So it idles fine until its warm, and then goes off on one side only? And which ECU are you running? You are certain its an entire (and the same) bank which is not firing?

Is there any way a lean miss type situation could be happening? Like a valve of some sort (EGR?!) opening and letting more air into one side? Interestingly enough my Skyline develops a slight lean miss (or something) once it has been running for about 5mins and I've never come to the bottom of it.

funnily enough my 4 cyl w/ link ecu develops a slight soft misfire after 5 minutes idling too

[RedMist]

As the trigger set isnt something Link have touched before its now running pre release software.
The fault just went away.... I had Walter switch it from sequential to batch fire and it started missing in both banks. Richen it up and it ran... switch it back to sequential.... no issue.
Definately ECU related... as to what it was. I have no idea.

[RedMist]

Does the ecu do data logging?

Can you do a firmware update? or would that require a retune?

CoilOnPlug setups seem to have problems with heat, so duno if that may be a factor.

Whats a set of ex temp probes and the innovate box worth?

Its already running a LC1. EGT is hard without making custom manifolds with bosses for K type thermocouples... and even then do they take turbo heat?
Fixed now anyway... dont know how... just hope it never ever returns.