Soarer Central: Car is Misfiring/Popping when hitting boost

Soarer Central Mechanical - TT General Mechanical Car is Misfiring/Popping when hitting boost

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Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 77
Reg: 11-2008

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Wednesday, July 08, 2009 - 02:46 am, by: Manual Kalianis (Manual_kalianis)

Hi guys I have searched all the misfiring/backfiring threads on this forum before deciding to start a new thread.

I am having a problem with my car, and it is not doing it all the time. When it starts hitting positive boost it starts missing/popping badly, on very light throttle or more.

The weird thing is it does not do it all the time. Some days I drive the car and all feels normal has good power no problems whatsoever. Then the next day I jump in the car and its missing/popping badly again when I start hitting boost.

I am going to Unigroup tomorrow to throw in a new set of plugs and recheck the tune in the TSI computer.

Looking at my EBoost 2 when it is under 0.0psi boost its nice and smooth. I give it a bit of throttle and once it goes over +0.0 psi on the gauge it starts missing/backfiring very badly.

I will let you know how I go with a fresh set of plugs tomorrow. At the moment I am running full copper plugs gapped to 0.75mm. Yuvuz put them in before tuning my car. He explained to me that on idle the car will miss occasionally but under WOT it should rev smoothly all the way to redline and it does what he told me.

The plugs aren't that old. They have probably done 5000km, 2 drag days and I have put octane booster in the tank a few times since the new plugs.

It is just weird that it is not doing it all the time and everyday that what is worrying me.

Niall reckons it might be ecu related.
My friend who is a mechanic thinks plugs or coilpacks.
And another local mechanic thinks because it starts missing exactly when I start hitting positive boost, it is turbo related, lol

Rob Rojo
Goo Roo
NSW
Soarer TT & UZZ31

Posts: 2472
Reg: 12-2007

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Wednesday, July 08, 2009 - 08:22 am, by: Rob Rojo (Rob_tt)

Could even be a problem with the map sensor or a leak in a vacuum hose.
While you have the plugs out check the coilpacks for cracks and use some araldite and heat shrink to repair them.
See if they can pressure test for any boost leaks while its there.

Daniel Clarke
Goo Roo
NSW
TT 2.5L 6 cylinder

Posts: 5214
Reg: 03-2006

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Wednesday, July 08, 2009 - 03:45 pm, by: Daniel Clarke (Dieseltrain)

Change the plugs, Unlikely they would die after 5,000km's but using octane booster can shorten life expectency .

If that fails, check the coil packs for cracks .

Possibly it could be map sensor related ( ie wiring ).

Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 78
Reg: 11-2008

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Wednesday, July 08, 2009 - 11:36 pm, by: Manual Kalianis (Manual_kalianis)

Thanks for the replies Dan and Rob (The 11.89 brothers), lol.

Went past Yuvuz. He took my car for a drive for around 20 minutes. It was only misfiring a tiny bit not as bad as it has been. But it was enough for Yuvuz to determine it is definitely not coilpacks or spark plugs. He is 99% sure. I am taking my car to him next week so he can investigate it further, he needs my car for a day.

I had work starting so couldn't leave it for him today.

I would like to thank Yuvuz, as he is flat out with other work and other customers cars, but he still found the time to take my car for a drive to see what type of problem I am having.

Hey Dan and Rob. You know my friend Raumin who accompanies me to WSID, I have converted him to a Soarer. No more 180SX. lol

He picks it up at the end of this week. Bloody bastard is getting a white Soarer like mine. Its a 1995 model like mine. It is auto like mine. But he has got the big daddy motor in it. Mr 2JZ-GTE!!!

I told him whatever he does to it to try and beat me, I am doing more to be faster. Its game on. lol

Nathan Hlad
TryHard
NT
soarer jzz30 tt

Posts: 345
Reg: 09-2008

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Thursday, July 09, 2009 - 01:08 am, by: Nathan Hlad (Jackpot)

dont know if you checked manual but maybe its only the boost spiking....

just a thought

Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 79
Reg: 11-2008

Rating: N/A
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Thursday, July 09, 2009 - 11:04 am, by: Manual Kalianis (Manual_kalianis)

Nathan Hlad wrote on Thursday, July 09, 2009 - 01:08 am:
dont know if you checked manual but maybe its only the boost spiking....

just a thought

Thanks for the reply Nathan. Its definitely not the boost spiking. It holds boost nicely as always.

David Tra
DieHard
qld
TT

Posts: 894
Reg: 11-2007

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Thursday, July 09, 2009 - 12:19 pm, by: David Tra (Bookie)

there is a chance the plugs might have been fowled after the new tune?

James Maddox
Newbie
ACT
1jz-GTE TT

Posts: 3
Reg: 04-2009

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Monday, July 13, 2009 - 11:33 am, by: James Maddox (Jimmythehand)

hey manual,

when you find out what the issue is leave a post in here,

i am having the same problem......

i was told it is the turbo outlet pressure sensor,

cutting off power to my turbo's,

and since i need a new dump pipe anyway.......

am going to get that done, and see if it fixes the problem................

Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 83
Reg: 11-2008

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Monday, July 13, 2009 - 12:02 pm, by: Manual Kalianis (Manual_kalianis)

James Maddox wrote on Monday, July 13, 2009 - 11:33 am:
hey manual,

when you find out what the issue is leave a post in here,

i am having the same problem......

i was told it is the turbo outlet pressure sensor,

cutting off power to my turbo's,

and since i need a new dump pipe anyway.......

am going to get that done, and see if it fixes the problem................

It has not done it again for the past 5 days. I filled up BP Ultimate and added 1/2 a bottle of octane booster and it has not missed so far.

I still have no idea what it is. But is there a chance that when I tuned my car with Yuvuz, my car had 98 octane + octane booster when it was tuned. And now I drive on the street I only put 98 octane and no octane booster when I fill up causing it to misfire as the computer is tuned for the higher octane fuel???

I will let you know James if it ever comes back.

Jeff Bedsor
DieHard
QLD
TT

Posts: 623
Reg: 10-2006

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Monday, July 13, 2009 - 02:19 pm, by: Jeff Bedsor (Jeff_bedsor)

Tuned on octane booster should make no difference unless it is tuned right on the edge where it will start to detonate. Most octane boosters do Sweet FA anyway.

Daniel Clarke
Goo Roo
NSW
TT 2.5L 6 cylinder

Posts: 5230
Reg: 03-2006

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Monday, July 13, 2009 - 04:18 pm, by: Daniel Clarke (Dieseltrain)

UNless your running the Nulon Pro Strength one .

With the cold weather , it can lean out the mixtures a little bit. Maybe it was leaning out ?

Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 84
Reg: 11-2008

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Tuesday, July 14, 2009 - 12:13 am, by: Manual Kalianis (Manual_kalianis)

Jeff Bedsor wrote on Monday, July 13, 2009 - 02:19 pm:
Tuned on octane booster should make no difference unless it is tuned right on the edge where it will start to detonate. Most octane boosters do Sweet FA anyway.

Maybe it was tuned close to the edge.

I got 240RWKW on only 14.8psi and I still have the stock dump pipes in it and 4 mufflers in the exhaust. I was only expecting 215-220RWKW maximum, maybe Yuvuz tuned it too far, I hope he hasn't. I have no idea. :/

Manual Kalianis
Tinkerer
NSW
2.5 TT

Posts: 85
Reg: 11-2008

Rating: N/A
Votes: 0 (Vote!)

Tuesday, July 14, 2009 - 12:18 am, by: Manual Kalianis (Manual_kalianis)

Daniel Clarke wrote on Monday, July 13, 2009 - 04:18 pm:
UNless your running the Nulon Pro Strength one .

With the cold weather , it can lean out the mixtures a little bit. Maybe it was leaning out ?

I only use the Nulon Pro Strenth occasionally. I did use it when the car got tuned. And I also put it in sometimes when I am drag racing.

Do you think maybe I got a bad batch of BP Ultimate and with no octane booster added caused it to detonate. I hope thats the problem. But I got a feeling it might be something else. I will be getting my custom airbox done aswell as my custom dumps in the next few weeks. I will fill up some BP Ultimate no octane booster and get it retuned and see what happens from there. I got a feeling I will need to change to bigger injectors after these two mods.