Misfire From Hell..

[arrydjay]

So my car was missing under boost...I tried second hand yellowjackets and new plugs at 0.8... Still misses...

Then I do a turbo upgrade with pretty much everything new.. Both manifolds, injectors PFC fuel pump etc.... Still misses...

Today I went and bought new splitfires and put em in...miss got worse.... Now it's like really loud backfiring... Different to before.

Has anyone got any ideas to help me solve this problem.

[arrydjay]

Also it's on e85 now running about 18psi... Are heat range 6 and 0.8 gap plugs right?

[ARTZ]

Also it's on e85 now running about 18psi... Are heat range 6 and 0.8 gap plugs right?

yes...its not your problem if thats what your asking

[Don Dada]

Youve added a shit load of stuff to the equation now....should have sorted it before the upgrade, but still check CAS and make sure the blue plug on the ecu is in evenly, pressing in the ends and not over tightening the 10mm bolt, And I assume u changed the afm to Z32?

When you say backfire, on accel or decel?

[DVS JEZ]

Has it been tuned?

[arrydjay]

Yeah it's missing on accel and sounds almost like a rev limiter with lots of little backfires..

Yeah it's a z32 afm and Toshi tuned it, we did what we could but we stopped when it was missing and I was going to go back and finish the tune once it's fixed.

[arrydjay]

Also it's only up high in the rev range and only at full throttle.

[SiR_RB]

Coilpack loom?

[Pezhead]

Try gapping down your plugs to 0.6-0.65. I just did that and sorted my cutting problem at 0.8 Bar. Now good all the way to 1.4 Bar. I think my coils are loosing power so confirms that it is spark related.

Running that gap now with no probs at all, until the shop warms up to re-mount my coils (I run bosch coil set-up).

[Don Dada]

Dont think its actually the coils..For reference my splitfires had enough juice to run a gtx30 @20psi with wmi and 1.1mm gap

Sounds like an electrical gremlin....As said before check coil pack loom, ignitor if you have one, also make sure all earthing on the engine and batt terminals are clean and tight and again CAS

What plugs you running?

[BitKeeper]

Check your fuel pump setup.

[On Edge]

So if you get mad backfiring an high in the rev range it could be leaning out coz of the pump?

[scotty nm35]

So if you get mad backfiring an high in the rev range it could be leaning out coz of the pump?

Definitely, mine did the same thing today on the dyno, changed coils, gapped plugs, no change. Ended up being one of the pos Walbro 342's not pumping properly. It seems they need to be fully submerged to operate at maximum flow, unless its just faulty... I was hoping the deatschwerks didn't have the same design flaw as this fault was occurring at 1/3 tank.

[arrydjay]

So I finally solved the problem!!!! Gapped the plugs to 0.63 and it's like a bat out of hell...

All that money spent when all I needed was feeler gauges...

[Don Dada]

What turbo and what boost? Thats a mighty small gap!

[arrydjay]

Yeah I know, it's strange because I'm only running 16psi atm with a Hypergear ss3eg with brand new splitfires

[Pezhead]

Well simple - small/hot spark > large/weak. I'm going to keep mine at 0.65. And my car runs a 500R CDI unit!

[scotty nm35]

Small hot spark = less powerz too

[hypergear]

I was running .80 gap pretty much all the time. Probably need to check and make sure it is the right plug. I accidentally used some CA plugs in there and it was miss-firing up top.

[On Edge]

Thanks scottym35