Car Running Too Powerful And Jerking

[kiz_baby]

Hi,

Wondering if someone can give me an idea as to what is wrong with my car. It's an auto R33 GTST with an AVCR Boost controller. When flooring the car it is cutting out for a split second at around 3500 revs.

I have checked and changed the air flow meter but still experiencing the same issue. My car normally runs at a maximum boost of about 0.75 bar or 0.82 in the cold when travelling upto 100km/h.

It is now achieving upto 1.07 bar at only 50km/h.

Awesome that it's so powerful right now but not so good that it's cutting out/jerking when putting my foot down.

Any ideas?

[hypergear]

AFM maxing out. too much boost for standard setup

[wolverine]

More boost = car cutting out

hmmm....

Have you tried lowering the boost to the previous level?

(this is a very commonly asked question btw)

[89CAL]

I don't think the stock AFM would max out that early. Hes probably seeing 210rwkw at the most on stock ecu (if it is stock ecu)

The afm is not maxing out. It is seeing abnormal air flow and putting the car into fuel cut or R&R which is causing the miss. There is a difference between maxing out the afm and what is happening here. Wind the boost down. 14psi is to much for a stock turbo and you may not see stable performance till you drop it to about 8psi

[The Mafia]

actually, the stock AFM maxes out at about 180rwkw. I usually tune around it. And the factory ECU cannot do 210rwkw. A tuned Powerfc can. A stock ECU with 10psi can make about 160-170rwkw. WIth rich and retard hitting, about 100rwkw at 12psi+

Your boost is too high. This is clear and simple.

With the factory ECU, Your car is hitting a rich and retard mechanism. This is your car telling you there is something wrong with the boost and to fix it. It is causing your car to cut out and do shit like that because its trying to stop you from blowing your engine and turbo.

Wind to boost back to 10psi and your problems will go away. If not 10, then try 9. DO you even have an after market intercooler?

This sounds exactly like the problem. 15psi is WAY too much for a stock turbo on a standard engine. You will blow it, turbo AND motor if you persist.

Edited February 4, 2011 by The Mafia

[Andrewtler]

I been running seemingly fine on mine mate. I also use the avcr and I max mine at 0.8 of a bar. If you don't have spitfire coilpacks it will cause this problem on most occasions as it is a known problem for r33s. Either way the only reason I run miner like this is because I'm waiting for my upgrade to be shipped to me so i don't care if my turbo blows up because I heard it only the exhaust side. Stick with the safe level of 10 psi I know it's hard to go backwards in performance but unless you got cash to splurge I'd do it. I think from memory 10 psi is approx 0.7 bar at around 50% duty cycle

[SECURITY]

when i was doing some data logging a while ago i noticed that the AFM causes R&R at two points. once if you hit ~3.8v @ 3600rpm and again if you're at ~4.5v @ 5000rpm or thereabouts. too much airflow through your AFM causes it to do what you are experiencing, not coil packs.

[luvpsi]

when i was doing some data logging a while ago i noticed that the AFM causes R&R at two points. once if you hit ~3.8v @ 3600rpm and again if you're at ~4.5v @ 5000rpm or thereabouts. too much airflow through your AFM causes it to do what you are experiencing, not coil packs.

yeah i ahve heard coil packs are good for up to 300rwkw on a series 2 r33. i beleive it would be fuel cut due to running to much boost on a stock ecu all i can suggest is lower the boost to 10psi at the most do not go over 10psi if you had an aftermarket ecu you would be able to prob sit at 12psi comfortably but with stock ecu no chance

[Andrewtler]

when i was doing some data logging a while ago i noticed that the AFM causes R&R at two points. once if you hit ~3.8v @ 3600rpm and again if you're at ~4.5v @ 5000rpm or thereabouts. too much airflow through your AFM causes it to do what you are experiencing, not coil packs.

I was having this exact problem in my late series 1.5 r33. I changed my coilpacks to the splitfire option and not only was the problem solved but I could run even more boost. I do think I'll drop my boost back though cause I'm a bit scared of detonation at the moment as I have done a fair few mods and haven't installed my power fc yet

Edited February 5, 2011 by Andrewtler

[R31Nismoid]

yeah i ahve heard coil packs are good for up to 300rwkw on a series 2 r33. i beleive it would be fuel cut due to running to much boost on a stock ecu all i can suggest is lower the boost to 10psi at the most do not go over 10psi if you had an aftermarket ecu you would be able to prob sit at 12psi comfortably but with stock ecu no chance

Stock coil packs are good for over 400rwkw without a problem if they are in working order. Same as splitfires, just more expensive.

It's the ignition amp that lets them down, not the coil itself. (aka: HKS DLI)

[SargeRX8]

People expect too much from their cars without spending. Spend at least $700 - $2000 on an ECU and tune and run your stock components to get power. You can get free performance to an extent.

Its not coil packs. My old r33 was making 240rwkw with 17psi and using std coils, as others have said. Your ECU is responding to the extra air.

[kiz_baby]

Thanks for the info. I'm running a stock ECU and yes I do have an aftermarket Apexi intercooler.

I can hear the air being sucked into the car as if I had a pod filter (I'm running a K&N panel filter) and the stock BOV is making sounds like an aftermarket model.

What would cause more increased airflow to the car? Oh and by the way I've turned off the AVC-R and still experiencing the same problem.

Edited February 5, 2011 by kiz_baby

[R31Nismoid]

R&R can kick in @ 9psi, it can not kick in till 14psi

That are FAR too many variables. Load, temp, airflow... Even accuracy of the boost gauge - all are factors mate.

There is not "magical" sweet spot.

IF you go back to 8psi and the problem is fixed - its quite simply ECU time.

[SECURITY]

Turning off the boost controller won't do anything except leave your boost levels unmonitored.

If you run a line direct from your wastegate actuator to your cooler piping it should sit at around 8-10psi. Check if this fixes your problem but keep an eye on boost levels at the same time, as well as how your vacuum hoses were connected to your avcr.

[Galois]

Coilpacks can fail at stock boost, I know, it happened to me. The nissan coilpacks are regarded by many as the best ones available. Think about it, cars being thrashed for 10-20 years so things will eventually start to go. But the point is they do go.

So if you're having ignition problems with ignition and you still have original coilpacks they're either the source of the problem, contributing, or planning a future problem for you.

They're also a relatively cheap fix, yellow jackets are $400 with a 2 year warranty, and everyone seems to say aftermarket coilpacks are a great upgrade.

[SargeRX8]

I just experienced something interesting and scary. Installed my boost controller today and got it set for 8psi. It fell off the mount and I was unaware my foot was touching the dial. I gave it a little hit and it took off like never before then the power vanished at about 5krpm. I pulled over straight away and my settings screwed up and I managed to hit 14.7 psi accudently, on a stock turbo and ecu. I shit in my pants and just let the car idle for a few mins to cool down. I get my new tuned ecu this coming week hopefully. Tuned for 10psi on stock everything apart from exhaust and fmic. With a good safe tune, 10psi and stock turbo should see around 180 - 190rwkw.

[DVS JEZ]

stock turbo and stock ecu can most of the time handle 14.7psi, but the stock turbo doesnt enjoy it.

what ecu are you getting?

are you going to get a highflow or similar?

[kiz_baby]

Hi all,

Finally got the problem fixed. Turns out it was a blocked wastegate caused by a split rubber hose.

[sucram]

boost cut

[89CAL]

boost cut

Not boost cut....... The ECU does NOT see boost in an R33 GTS-t.

The ECU see's air flow, Injector duty etc etc. See's variables out of its programmed range and throws fuel at it and takes timing out

You can not call this boost cut