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View Full Version : Ignition problem? Car suddenly misfires at 20psi and never did previously!


codyace
09-24-2006, 06:22 PM
Hey guys:

I've had my car running all summer now. Just a simple setup (JWT ECU, gt2871r .64 turbo, Cobra MAF, 60 lb injectors, proper timing, stock ignition etc etc)

I've ran BKRE7-11's forever now, and had zero problems running 20psi for 4/5 months. We went up to Watkins Glen this weekend, and in the 2nd session, we noticed the car was breaking up in the upper RPM when running 15 psi. Not wanting to blow up the car, I decided to park it, go down town, pick up some PFR6G-11's and throw them in for the ride home.

Car drove home just fine (in fact, getting 30 mpg!) and runs in 10 psi just fine with no hint of misfire.

So I let the car sit for a few days, and decided to go out and check things out. Everything appears fine, and no leaks are spotted. Running 44 Fuel pressure when vacuum is pulled off the nismo regulator.

I run it at 10 psi, no problems. Even doing some full 15 psi pulls. However as soon as I switch over to the 20 psi setting, it imediatly breaks up in boost (I'm not one to stay in the hammer, as soon as I feal it break up, I let out)

Now after doing some searching, I've got some ideas to include: Ignitor, Coilpacks, CAS.

However, with most of those parts, I've noticed that people replace them when they experience overall poor performance. I don't think any of them would be terribly bad, as I was getting fantastic mpg, and it still pulls strong witht he boost controller off.

If anything I'm thinking I'm just running out of spark output up top, but don't know where it's releated.


Just looking for some opinions on a possible solution. I tend to think it may simply be just an ignitor, but in reality I am doing nothing more than shooting in the dark.

street_white180sx
09-24-2006, 09:06 PM
check your plugs. when u have a problem like that when in high boost its usually jus the plugs either they need to regap or just change.

codyace
09-24-2006, 10:12 PM
They are new plugs though? That's what baffles me :(

rim_bender
09-24-2006, 10:46 PM
They are new plugs though? That's what baffles me :(

gapped to what?

better be .028 or smaller

street_white180sx
09-24-2006, 11:16 PM
yup if u dont gap them .28 or smaller it will break up. gap is very important in hight boost applications.

street_white180sx
09-24-2006, 11:20 PM
i jus read u went to a hotter plug. that will cause it as well. buy sum colder plugs like you had before. and make sure your not leaning out up top. becuase when u lean out it breaks up as well.

codyace
09-25-2006, 07:12 AM
/\ /\ That is something I will certainly try today! I've got some spare copper 7 range plugs here that may work...! I never even thought about the heat range difference at the time.


And my gap is actually at .020/.022 (The carquest at Watkins Glen only had one of those round gauges...so as close as possible.

codyace
09-25-2006, 04:04 PM
Same result with the 7 range BKR's.....gapped at .022 this time as well...

street_white180sx
09-25-2006, 06:09 PM
damn. might be a weak coil. but also make sure your not leaning out u cud have a dirty fuel filter check ya air fuel gauge.

codyace
09-25-2006, 08:21 PM
A/F gauge (PLX M300) says good...high 11/s low 12's

I'll check the fuel filter (Z32) as well....

Per FSM I'll check the injectors tomorrow....

It just kills me that it's only a 20 psi...no where else lol!