Failing Splitfire Coilpacks

[lcy]

Hi guys and gals!

I am currently having some misfiring problems. Yes i have change it to SPlitfires which are only 14 months old. Mechanic reckons thats the problem. Maybe a faulty one. Low boost doesnt misfires but when i am on high boost it misfires.

So i have been told it might also be the AFM but it has been changed to a new one. Spark plugs are new. We are eliminating the CAS, as the tuner says the power graph doenst show irregularities.(or something like that, power doesnt goes up and down)

What could also cause this problem??

If any of you guys ever had this problem pls let me know!! Any help would much be appreciated!!!

THANK YOU IN ADVANCE!!!!

[The Dan]

Fuel

[lcy]

Nope... check new fuel pump + bp 98 only.

The car actually doesnt misfires that much when i had a service. Before the service it does misfires alot. Service was just a regular service(oil + oil filter).

This doesnt happen all the time. Sometimes it can work like a dream and sometimes its being a bitch!

[Ultimategtr]

Instead of changing the AFM/PLUGS etc and spending money on those things, the VERY first thing one should have done(i know i would have), was run a diagnostic on the stock ecu(if its still stock).

Checking simple things like timing, fuel pump pressure etc.

What gaps are you running?

[The Dan]

+1 for Timing.

Check to make sure the CAS isn't wound too far forward. And as for fuel, does it have a new fuel filter on it as well?

[180or200]

what do you call high boost, could still be blowing out! even with splittfires I have to run a .6 gap to run any higher than 17 psi

[lcy]

I am running PowerFC. Timing was drop, tuner says nothing wrong with the CAS.

When the car is on Low Boost (10 psi) it doesnt misfires but on 16psi it just goes POP POP POP around 5k rpm....

Will check on fuel pump pressure and fuel filter(is this the one on on the fuel pump? If so it should be new.)

Car is running a gt30, fuel pump, 650cc injectors, z32 afm and all the usual upgrades. Tune looks very good. 12.1 afr which really cant be justified because every engine might have a different characteristics.

[paulr33]

go see a mechanic and check it on the dyno

each time it goes pop pop pop its doing damage

[lcy]

I had already brought the car back 4 times since i got the car back. Tuner still reckons its the coilpack that needs changing. Final!

during the tuning process the enigne didnt even misfire at all! On the dyno it didnt misfire hence the tuner didnt even know it was happening.

Its when i brought the car back and took it for a drive, it started to misfire and pinging (engine light keeps popping up on 3rd gear). So back to the tuner again and timing was drop and everything seems fine but its still misfiring on 16 psi.

[lcy]

Just added: Dyno 3 times. Didnt misfire on dyno and car made 350rwhp on first tune then timing drop it was making 320rwhp.

JUst to add some info. THe car was tune by a reputable tuner.

I have brought my car to several different place and have been told off many times. Everyone has a different story and some doesnt want to touch the car as most said "Trust in your tuner furthermore he is the best around!". This are from mechanics and tuner alike.

1st graph = when i first got the car

2nd graph = timing drop

afr2.pdf

Edited March 29, 2009 by lcy

[SECURITY]

im just having a stab in the dark here but this could be leading off your white-smoke problem in your other thread. if you've got water entering your combustion chamber then it will misfire.

fix your other problem first.

[lcy]

Not that i am not trying to fix it but tuner/mechanic says it is just condensation.... nothing more.... they are not really worried about it.

So this is putting me in a dilemma, not knowing what i should do.

[aphid]

I would agree and say that it definently sounds like a coil pack problem.

Splitfires arn't infallable, infact in another 2-3 years time when some of the originals start getting older I'd put money on it we'll see more fail in exactly the same fashion the stockies fail.

Just to make sure swap it with a known good pair to see if that makes any difference, and like others have said I'd also be checking your plugs / plug gapping just to be certain.

Good luck!

[Lithium]

Spark plugs are new.... what gap are you running with them? The ignitor is something else which can play up, too.

[Ultimategtr]

Just to take a wild stab - 1 way to find out if the coils are on there way out is to measure the resistance between A-B(i think - as per factory manual).

Now i know that the readings in the manual are for stock coils. However the readings you get, write them down and compare them individually.

eg coils 1-4 have around 20k-22k resistance where as 5 and 6 are getting 29k.. that would "KINDOF" indicate that 5 and 6 possibly could be faulty, judging their resistance. This method is only going to test the primary coil tho, not the secondary coil.

Thats 1 easy way of testing it, the other is to take the coils out and take it to a professional sparky - where they can load up the coil to a few hundred V on their test bench and see if theres anything wrong. This would be better - as the coil heats up, the resitance would too, therefore this test would be more accurate.

[JonnoHR31]

what type of plug and what gap?

[lcy]

ngk 6 (not sure what is the actual code) havent try regapping as the mechanic says no need to regap when you have splitfires.

Will try to see if ignitor and also "professional sparky?" means auto electrician?

[docang]

Try checking the coil harness as sometimes they give problems especially the connectors as they are prone to get loose after some years of connecting and disconnecting and also greatly affected by the engine heat.

Even after 2-3months on a third new coil harness my engine was intermittently misfiring and my mechanic did some mods to the connectors by trimming some plastic bits in them for better contact and this cured the misfirings. Leaky valve covers gaskets will also let oil get to the plugs causing misfiring and this happened to me just this past week.

Edited March 29, 2009 by docang

[JonnoHR31]

pull the plugs out and check the gap, if its 1.1mm then gap them down a bit

[The Dan]

pull the plugs out and check the gap, if its 1.1mm then gap them down a bit

why?