Turbo shuffle / misfire / hesitation

[andy66]

R32 gtr , stock boost and turbos, stock downpipes with a full a/m 3" exhaust, hks front mount intercooler and apexi intakes.

I`ve been dealing with a crazy hesitation/misfire/ turbo shuffle for a while now and so far everything I've tried has only solved it for maybe a day. So far I've re gaped my plugs , re soldered the mafs and cleaned them , checked the tps with a multimeter , checked the coils they were all within spec at 0.7, checked the little springs on the coils as well they all looked fine and ive reset the ecu. Only things I can think of that i haven't check are the coil wires and the ignitor.

Normally the symptoms will kick in under light throttle right around 2500-3000 rpm or just as ithe car comes onto boost. It's been intermittent on and off for the last while. Some days it won't happen and others it will. When it does happen you can hear the bov going off repeatedly. It doesn't seem to do it if you floor it , it still reaches full boost and pulls hard its just when you're under normal acceleration under load. Revving the car in neutral there's no issues only under load does the car act up.

[markdett]

Do you have any codes in your ECU? If you have an ignittion primary code id be putting a fresh set of coils in it, with new plugs happed to .6-.7mm

The problem your describing does sound like the classic igntion primary fault though.

[Terrh]

Every GTR that i've owned or have been in has had this issue at some point. The ECU isn't advancing the ignition timing because something is making it unhappy.

I wish I could say I had a concrete solution to what solved it but I've tried many things with varying amounts of luck.

Things to check first:

that the main ground cable is in good condition and isn't broken/worn/whatever. Same with the + cable and the battery terminals themselves.

The small grounds on the engine are clean, most are right by the upper rad hose.

The ignitor has a ground on it too.

Sometimes turning my car off and back on would fix it, or putting gas in. Sometimes it wouldn't. Changing the maf's fixed it in my friends car for a month before his started doing it again.

Any water getting onto spark plugs (sometimes the plugs in the head leak) can cause misfires or weird stuff too.

[andy66]

Could having a really beat up coil harness and a bad ignitor cause this to happen ? Or even a boost leak somewhere or vacuum leak? I forgot to mention my GReddy boost gauge will go nuts and the needle wont give me a steady reading it will shake up and down when this is happening.

[Voodoo_ChildR32]

Coil harness wound up being an issue on my old gts4, replaced it with a known good one and problem solved. It's worth taking a look at.


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[andy66]

Were you having the same symptoms as I was having in the vids ? I had a coil pack go out on my other gtr and it developed a really bad misfire but the bov would never go off. That's the part that has me confused at the moment. That and my a/m boost gauge getting all squirly. Ive got a new set of wires coming this weekend hopefully and a new ignitor. ill start with that and see what happens. fingers crossed because im getting really tired of chasing after this problem.

[Voodoo_ChildR32]

Didn't really notice BOV sounds on mine, it was an rb20. I definitely had a bad misfire tho. Sounds really weird in the vids. Kinda like ur on boost then off then on. Also noticed ur oil pressure gauge at zero as well, is it unhooked?


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[h4X6]

Kinda having the same issue with my rb20... watching this thread for a solution...

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[andy66]

So as the days go by and im still chasing after this problem im starting to notice more and more that the car will run , idle and boost fine until the car's been driven for a while and has gotten hot. After that point the symptoms start to come on.

I picked up a set of wires yestrday and that seemed to help a lot but after driving around for an hour or so last night it started to misfire and hesitate again , not as bad as it was doing it before though.

So Im leaning towards a bad ignitor since ive crossed the wires off my list and my coil packs all tested at 0.7.

[h4X6]

Is there n after market solution or one that can be used from another car?

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[Skym]

Injector loom, coilpack loom are the known causes of missing. Ignition module can cause stalling of engine after roughly 10 minutes of driving, but is also know to cause engine to run on less cylinders (check it via oscillioscope and sometimes tapping ignition module lightly makes it play up, but be careful as the housing is easy to crack).

Even a airleak behind MAF's can cause stuttering (MAF's gets two air sources instead of one) and can be traced back to crack in rubber intake piping (common problem) just after MAF's, loose intake hose clamp (or crack in rubber intake piping under intake hose clamp), etc (any airleak). This can often be mistaken for missing coilpacks which produces similar symtoms, but usually only happens at lower rpm after exiting motorway (I have had this problem on my car).

Sometimes there's an airleak between airfilters, MAF adaptor (clamp on via hose clamp type of airfilter), causing ECU to hit boost cut (revlimiter). Bolt on type of airfilter from Apexi solves this problem.

Shuffling = inbalance in exhaust flow to 2x turbo's, so engine running on 5 cylinders would do it. Also shuffling can be caused by internal wastegate actuator (have to be same psi on both turbo's). Coilpack, injector loom, leaking injector. Basically anything that changes amount of exhaust gas to turbo's. In some cases ECU tune, injectors (majorly different cc injectors, not within 1-2%) or ECU itself.

[andy66]

I've replace the coils with known working ones , checked the tps voltage and adjusted it, ive changed my plugs from BCPR6EIX-11 to BCPR6ES ,re soldered the mafs and cleaned them , swapped in another set of coil wires , checked the ground wires for the coil wires and from the ignitor, taken off the rubber turbo intake pipes and inspected them for cracks and didn't find any. The ECU is giving me a code 55 for all clear.

Still having the same issues , will start fine and idle fine but after a few minutes of driving the same symptoms come back. Audible misfire sound at idle most of the time, hesitation and misfires when light throttle is applied just before/boost starts to build and that same sound from the vids i posted. WOT throttle there are no issues it pulls hard and doesn't miss a beat.

Runing out of ideas any other things I can check / try ?

[clone]

RightDrive fixed mine by changing:
cam sensor & ignigtor

[RixR32]

Do a compression test with the engine cold, then with it as warm as you can get it. Compare cylinder variances between the two.

Try the ignitor if you haven't already.
I assume you've done the "unplug one coil at a time" test when its doing it when idling?
Coils and ignitor are both known to test ok, but fail when hot.

Rick

[clone]

RightDrive fixed mine by changing:
cam sensor & ignigtor

Sorry forgot the also found a corroded wire to the ecu near the fire wall.