Miss Fire On Dyno Rb26 Any Ideas?

[portaz]

Well now I'm screwed still exactly the same and even Andy from adaptronic has no idea. Tried new coils , plugs, injectors, cams , checked compression, checked cam gears checked all new joins as in ballast resister and injectors , I really don't know what else to do? I love this car and it means alot to me sentimentally but my brain can't take this , I don't think I can pull it out and start again financially or physically

[SiR_RB]

Far out that's not good man that is a very weird problem indeed !!

Did they change the ecu over??

[portaz]

Yep

[Piggaz]

Checked the ignitor?

[portaz]

Ignitor was changed with a known working one

[SiR_RB]

Du no if this is relevant but any chance the coil packs are r34 gtr ones and not 32/33 gtr ones??

[portaz]

No they are 32 ones off my last engine that worked perfectly

[Sinista32]

Not qualified but are all earthing point straps secured and to correct components ?

[portaz]

Yes and even tried new earths for coils and ignitor

[Sinista32]

Fuel delivery pressure and Fuel quality ?

Actuators ok ? (misfires @ 9psi consistently )

what's the RPM when it misfires and how bad is it? Can you go passed it ?

Any anomalies in the ECU data logging

Summarising change overs, anything else ?

ECU X 2

Injectors x 2

Plugs x 2

CAS x 2 ? + adjusted dwell

Coil packs x 2

Coil Pack harness (new)

Ignitor x 2

Earthing x 2

CAMS replaced to stock

Cam gears

You maybe right - something under pressure within the head/block (Mechanical).

All the external gear seems double checked

Edited June 1, 2013 by Sinista32

[portaz]

As its still at dyno I havnt been as to drive it myself, from 9-11 psi I'm told , only under load so my plan is to get jez to try a nisstune see how that goes failing that do a safe tune so I can get ur home. I'm thinking leak down test first as comp test was perfect , next put 15psi into cooler piping and check each port with inlet valves closed for leaks, possible injector seal issue maybe pushing out under boost as they are not factory seals and are a little small for manifold compared to stock. Next is create a daisy chain from each coil to earth and possibly a relay and direct power from battery. Failing that run new jumper wires from ecu direct to each coil. Triple check injector wires and ballast wire joins. Lastly strip harness rig up a buzzer to each injector wire and sensor wire and somehow apply 12 v at ecu end and listen while moving harness for any changes that may indicate slightly broken wire. It's got me stuffed though it sounds perfect and passes every test except when boost is applied, I really don't want to strip engine down and jez doubts its internal , oil pressure is perfect as is temperature he said slight bubbling in rad after run on dyno but is normal I'm his experience.

Other than that sell it on and give someone a bargain but I met my wife in this car so it's very sentimental but with my mental health at stake I can't take much more

[scotty nm35]

Just get Jez to drain that crap 98 out of the tank and run e85 from now on, no more knock.

[portaz]

It was fresh 98 with e85 waiting to go in but he tunes 98 first

[GTScotT]

Its got to be electrical. Can't be mechanical man.

has jez tried just flat out doubling the dwell? Dwell is hard to work out what's best at times.

failing that what are the AFs doing under boost when it cuts? Does it chop and change or is it consistent?

[portaz]

I asked about dwell him and Andy Played with it not sure in result af ratio see saw all over the place once boost starts coming on

[portaz]

Does anyone know if stock ecu is wasted spark setup?

[SiR_RB]

this is a mystery mate, dunno what else to suggest ?

[GTScotT]

If the AFs are all over the shop when boost starts to come on you better look into all things related.. Try smoke test it at 15-20psi and try a different set of injectors.

To me its either going to be an intake leak which is very close to the ports/injectors or its going to be a fuel control issue. So maybe injector seals giving out, FPR or pump failing under load or injectors failing under equalized pressure.

Time to start fiddling with the above.

[portaz]

The only thing that isn't new is the nismo fpr, mmm I wonder and I'm a little concerned about seals pushing out under boost even though they are new , intake gaskets are nitto metal which I sprayed hilomar and torqued to spec and have never had issue with these on the last two engines, it turns out stock ecu isn't wasted spark I wonder if that's a possibility?

[Adriano]

do you hv a plot of the afr's, ignition breakdown will show up as lean spikes