Boosted Coyote Missfire problem 2500-3000rpm and Inj-Cut at WOT

[G-Town-GT]

Hi Guys,

just built the following: 2017 Mustang, VMP Stage 2 Gen2 with 85mm pulley BAP 56 injectors Brisk 1 step Colder plugs Gap .030 / Aftermarket exhaust / Long Tubes with cats.

Calibration file is a copy of my own car with the exact same Hardware settings exempt different aftermarket exhaust and it runs just fine.

The problematic one runs fine at idle and crusing in the city up to 2500 RPM. Going into boost the trouble starts.
It throws an Cyl 8 Misfire DTC at 2500-3000 at part throttle, at Wot and while in OP it does an injector cut and leans out ! ???

Cant wrap my head around it


Please have a look in attached log, all relavant PIDs for diagnosis should be present.

L_1.hpl

[G-Town-GT]

Forgot the second file: VMPGen2_56inj_BAP_85mm_1.0.hpt

[Bill@HPTuners]

I would start by pulling the plug & checking the injector harness connector.

[G-Town-GT]

I would start by pulling the plug & checking the injector harness connector.

Hey Bill, thx for your quick reply, did that already, plug looks fine, Injector connectors are seated fine.
Why in all world would the ecu command Fuel source: Inj Cut at WOT in OP and of course with that go lean? Log time: 4:43:24
Additionally I see a Cat Temp Enrich and it is commanding a much higher Lambda compared to what is in the cal file (0,71) Log time:4:43:35

[rcmikey]

Did You notice during idle you are commanding .88 and your wide bands are reading 1.02ish. I can see that it falls into open loop right after hitting your cat temp limit. It then commands lambda that follows your cold base fuel table. Also noticed you cat temp is reaching its limit during cruise and seems to stay at the max. Not sure if this is what is forcing open loop but if you look at your entire log it goes into cat temp protection then right into open loop. I can see why it is so lean at WOT, its in open loop and following the cold fuel table. It never goes into WOT fueling. The #8 misfire is just a result of a lean condition. My last thought is that if it works great in your own car but not in this one, I would look at the cats to see if they are melted.

[rcmikey]

After studying your log I can see that it has gone into open loop fault. My experience has been it is caused by a faulty o2 sensor signal. Do you have o2 extensions? You can see that B2 is reading way lean until you do the WOT pull and the after letting off the signal comes back and all goes back to normal. Hope this helps

[GHuggins]

The lean condition can also just be the misfiring - excessive oxygen going into the exhaust from a non burning cylinder... Coyote's are really really bad for ignition coil issues under boost... If you still have cats - do as advised and check them - also check everything else that was recommended, but keep the coils in mind... For any coyote track car build, I now always recommend coils and an ignition voltage booster with the build...

[G-Town-GT]

Hey, thank you guys for going through my logs.

Not the Coils but the plugs ! Since I did not have a second one step colder set of plugs on hand, I swapped back to the original ones that the vehicle came with, gapped them to .030 - Problem solved! So one or more of the plugs were faulty.

@rcmikey I first thougt exactly in the direction you described. After all - GHuggins idea was correct: "The lean condition can also just be the misfiring - excessive oxygen going into the exhaust from a non burning cylinder."

As easy as that just a plug, but still unbelievable that this causes such enormous fueling failures in all areas. Coyotes are such Divas ! ;-)

Once again thanks to all of you for your support, and dont trust new plugs!

Cheers
Mark

[Bill@HPTuners]

could just be your gap too, I believe those brisks come pregapped at .028, maybe just getting spark blow out

[G-Town-GT]

could just be your gap too, I believe those brisks come pregapped at .028, maybe just getting spark blow out

The Brisks and the NGK's must be gapped for boosted applications, the Denso ITV22 comes pregaped for boost.
I always gap them to .030 at the smaller boost levels (85mm pulley ~ 10psi)
This has so far proven to be enough to me even at up to 14psi.

[rcmikey]

Hey, thank you guys for going through my logs.

Not the Coils but the plugs ! Since I did not have a second one step colder set of plugs on hand, I swapped back to the original ones that the vehicle came with, gapped them to .030 - Problem solved! So one or more of the plugs were faulty.

@rcmikey I first thougt exactly in the direction you described. After all - GHuggins idea was correct: "The lean condition can also just be the misfiring - excessive oxygen going into the exhaust from a non burning cylinder."

As easy as that just a plug, but still unbelievable that this causes such enormous fueling failures in all areas. Coyotes are such Divas ! ;-)

Once again thanks to all of you for your support, and dont trust new plugs!

Cheers
Mark

Please post a log file of a good run. Curious to see what the WOT fueling is doing along with the fuel sources. Did it stay in closed loop without falling back it open loop? Its amazing on how much background logic is effected once a misfire is detected.

[GHuggins]

Brisk silver racing plugs are very sensitive to install torque - I use my little 3 inch long ratchet just to make sure I don't over tighten them. They're my own personal favorite plug to use as long as it's not one of their Bosch quad want to be plugs. For the Fords I primarily use NGK's, but I know there are better one's out there. Then depending on actual boost levels I might even run a stock plug - colder plugs aren't always the best route to go... Then as far as the coils goes - I haven't had a track car yet last for two complete sessions before a coil drops out on 10ish or more lbs of boost...

[G-Town-GT]

Stays in CL during WOT, fueling is pretty much in the Ballpark, still a little Speed Density tuning to get rid of the negative MAP spikes and some WOT Spark tuning for next week.

What do you think?

GHuggins, I checkt those Brisks visually for Isolator cracks but could not find any. I have a mini Torque wrench for that and use 15NM, this is what I got from NGK. They say 10-20 NM. NGK is also my choosen brand, but I am currently out of stock. Yes the Bosch Quads..... :-) I thought they were not even out there any more.... I had them once in a Golf VR6 as the came out..... car was running like crap.

Switched to MSD's on my Coyote and the Misfire at 4500 even doubled. But I guess this should be a nother thread.

KH_Pull_4th_5thmodulation_on.hpl

[15PSI]

I run the Brisks at 13-14 PSI (.028 gap). I have not found a plug as reliable as the Brisks. There is no substitute for silver as a conductor. My second choice is copper. On boosted applications, I stay away from Iridium as they overheat in boosted apps. Actually replaced my stock coils with aftermarket higher voltage units. The aftermarket coils misfired after about 2K miles. I put the stock ones back on and have not had issues. Go figure.

[GHuggins]

I won't use MSD coils on anything much anymore - never seen a coil fail as badly as these are right now I know they had an iffy reputation when they first started out, but weapon x is the only company I use for Ford coils or ignition components anymore just from field testing and how well they plug on to the plugs, fit and work under extreme circumstances... They are pricy, but...

http://www.weaponxperformance.com/ca...eyword=ick8214

Then their ignition voltage booster that I always use with the coils is a TIEK1412, which they don't have listed on their website... I always just call them up when ordering...

[rcmikey]

I won't use MSD coils on anything much anymore - never seen a coil fail as badly as these are right now I know they had an iffy reputation when they first started out, but weapon x is the only company I use for Ford coils or ignition components anymore just from field testing and how well they plug on to the plugs, fit and work under extreme circumstances... They are pricy, but...

http://www.weaponxperformance.com/ca...eyword=ick8214

I see that these coils are advertised to be sent with a value file. Is the value file only good for SCT?
Then their ignition voltage booster that I always use with the coils is a TIEK1412, which they don't have listed on their website... I always just call them up when ordering...

[rcmikey]

I see that these coils are advertised to be sent with a value file. Is the value file only good for SCT?

[GHuggins]

I've honestly never changed the tune for them - I know there's usually power to be gained with dwell changes on AM coils, but when I change things like that - coils lives always seem to take a nose dive, so I've started leaving that stock... If the file is in SCT format, it's easy enough to open in SCT and then copy/paste into HPT... Time consuming, but easy enough...

[rcmikey]

I'm running stock coils on my GT and have been for the last three years on the track. Have yet to have coil failure but I am sure it will occur soon. I have added a little more boost and now the power falls off at 6500rpm. I have been told its the blower running out but the boost doesn't fall off. In fact the boost will continue to rise after the power starts to fall off. Might be coils not strong enough?

[15PSI]

What blower are you using? I have a GEN II TVS and have not had any issues with limitations from higher boost. And as I said, at 13 PSI or so, the stock coils work well for me. But I don't shift it to the moon either, always around 7100-7300 at the dragstrip.