MR

Hi,

I have the below msg posted in the engine/turbo/drivetrain folder...I was wondering whether this misfiring might have anything to do with the AEM that my fren is using...I will be going to do a similar setup as him as i am persitantly trying to to find a answer to this problem of his.

SOme folks did mention the AEM have issue with boosting high at hig rpm & also if coupled with a cdi, it will fry the coil packs too...so if this is the case, wat advice would u aem guys advise? Anything to look into the AEM aspect?

Many thanks....

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Hi guys...

A friend of mine has been having misfiring of his spark plugs...

He has a 2.3L block, ported & polished the top, 270 cams, walbro & a paxton external fuel pump, after-market intercooler, fuel reg, bigger fuel rail, aquamist, GT35r .82 & AEM on his evo.

He is boosting at 2bar....

But after a couple of pulls on the road, the mis-firing came in. ..the boost just flutters & the engine stutters....

He put in a HKS twin power & changes his plugs to a set of NGK which is a range colder than stock. Still happen after a couple of runs.

Than he decided to change to NGK racing which is number 9. Regapped it slightly. Same cycle repeats...

Wat could this be?

Thanks...

GTVEVO

iTrader: (22)

Honestly if you friend wants to move on and get rid of this issue he needs to run a full coil over plug ignition setup (coils and box). It is honesly the last thing I would know to try but it is also one of the most expensive. Many people run these without issues.

Sounds like he needs to find out when and why this actually occurs. At what boost level or what RPM level so you can figure out where they fail. This way you can figure if it is the ignition or somthing talking to the ignition. Is he trying to do 2bar with water/alky injecton or race fuel?

racegate

iTrader: (1)

The EVO coils are real hit/miss its seems with the EMS. Half of them will work fine, half of them won't. Looks like your friend just needs to bite the bullet and seek another coil solution. A CDi box definitely seems to take its toll on the coils eventually.

One thing to try is to gap the plugs down real low. Try .022, then .020....

MR

As a matter of fact, he did coil 0n plugs with aem cdi2. Still misfire...ANy pointers to take note when using this coil-on-plug with aem cdi2 setup?

Than he revert to hks DLI2 using back the stock coils.

He has aquamist mist installed but it is purely water with no methanol mixture.

He did with normal petrol & oso with race fuel...same cycle repeats itself. The misfire seems to happen at 5500rpm.

GTVEVO

iTrader: (22)

At 5500 rpm it is the sweet spot for knock on the 4g63 evo motor. I would be looking at knock in the log and back off ign timing to see if you are feeling knock after the car heats up or the coolant/ign trim table could be jacked up. If you are it is enought for the AEM to be yanking ign timing out and pressing it back in quickly depending on the setup. Be aware if knock is bad enought your rpms will drop and the car will studder. 2bar with normal pump fuel and water injection running only water is a little much on this car from the sound of it.

Also looking on other posts make sure the plugs are gapped < .024 (.022) is what I run.

kcevo

iTrader: (11)

GTEVO, not to step on your toe's, but just to add a little to this. In regards to the knock, this will only happen if you are tuning with knock control turned on. Also, with the addition of the amplifier box (AEM C2di, MSD, HKS, etc.) you should be able to open the gap of the plug back up because it is a hotter spark. When I was testing my setup (AEM C2di w/ 4 MSD blaster SS coils) I saw some misfires at 28psi and .035 plug gap on BPR8es's running 110 octane. Re-gapped to .032 and the misfires went away.

GTVEVO

iTrader: (22)

You are correct. I am assuming that he is using knock control.

Widebandphillip

iTrader: (1)

Running speed density? I got some misfires on a utec with a maf sensor and a leaky stock bov. Post up a log.

MR

i will try to get some datalogs from him & get it posted in here....

racegate

iTrader: (1)

Try gapping them down a lot to begin with. .022 or so. And see what happens. You really shouldn't need that kind of gap with a CDi box though. But there could be something weird going on.

Also a cal and some log files logging the important stuff may shed some insight into this.

MR

Been bz these couple of days...will try to get hold of a cal and some log files to post them here.

- HKS DLi is in
- Plugs all gapped to watever that has been advised
- Check for any leaks..no leaks
- New coils

My friend & myself consulted some local tuners & has been advised to look into the fuelling system again.


We decided to change his in-tank High Pressure pump to a Walbro instead of the 210L Power Enterprise ( My mistake, thought he was on 255HP pump) & replaced the pump filter to a new one. They figured that fuelling might not be enuff.


Will post a update once the 255HP L Walbro is in.

MR

ok...The misfiring has been resolved....

It is due to the fact that the fuel is not being flowed to the injectors fast enuff....He placed a Fuel-Surge tank to the paxton pump & all of a sudden the misfiring just went away.

I also dun understand why a fuel surge tank will resolved this particular issue of his. Any elaboration from you folks here?