R34Gtt Strong Cut,power Loss On Acceleration

[B-rice]

After changing clutch I noticed during test drive that I have a strong cut- momentary powerloss till i lift off the pedal. Its almost like a cylinder cut or fuel cut that happens when the traction control kicks in. Usually happens when car has warmed up and on slightly hard acceleration. If revs/speed is built progressively the cut is not present.

Ive tried swapping the CAS as someone mentioned that their CAS was the cause of this.

Also tried unplugging and plugging the boost controller and MAP sensor. Im running MAFless so ive ruled out the AFM.

Anyone know what this could possibly be. Have tried a few things and im not able to pin point the problem.

[wedge_r34gtr]

coilpacks?

[B-rice]

might buy a pair through streeter but wouldnt it be constant throughout? the rev range

[wedge_r34gtr]

No, it depends on the quality of spark they are producing - it's harder to ingnite fuel on boost (higher pressure, richer mixture etc)...so it could be fine during during low rpm operation. Best bet is to borrow someones coils that are known to work and see if they fix the problem.

If this doesn't work, i suggest taking it to your tuner and get him to have a look at the ecu map.

Also check you didn't dislodge/damage any wires when you took your gearbox off. Not sure what could cause this that runs near the box though.

[B-rice]

Some progress or maybe just a little. Took of the intake and tested for boost leak for the second time. None were found,

Took my boost controller off and connected the wastegate directly to the cooler piping niple. It seemed like it worked at the start, managed to get it boosting up to 1/2 bar. But it was only because the car was still cold. The cut out is comes back when the car gets up to operating temperature.

Disconnected the wastagate and the flap is moving freely.

Took out the coilpacks and reconnected them with new spark plugs no luck.

Waiting for coilpacks to arrive hopefully that should fix it.

[sonicz]

Have you tried going to 0.8mm copper plugs? Something like NGK BCPR6ES. Getting new coils is always a good idea. The fact that your problem arises when the car is warm points to a coil fault. I recommend yellowjackets over spitfires simply because I have never heard of anyone having problems with them and they have been fantastic in my car.

Edited January 25, 2014 by sonicz

[scotty nm35]

How much fuel is in the tank? It may be surging on acceleration.

[B-rice]

How much fuel is in the tank? It may be surging on acceleration.

inbetween 3/4 and half. Thought so aswell at the start i even thought the pump is dying out due to low voltage so i jumped in the boot and a mate drove around while i was checking the voltage 13.4v constant the pump. Also thought the rubber intake was sucking shut so I took it off. Will be contacting you soon for a metal one.

Have you tried going to 0.8mm copper plugs? Something like NGK BCPR6ES. Getting new coils is always a good idea. The fact that your problem arises when the car is warm points to a coil fault. I recommend yellowjackets over spitfires simply because I have never heard of anyone having problems with them and they have been fantastic in my car.

Ive already ordered Splitfires through JesseStreeter, soon as they arrive ill update if it fixes just incase someone may have the same problem in the future.

[B-rice]

Just an update kind of really pissed that i changed the coilpacks and sparkplugs and the problem is still there. Car still randomly looses power when building boost or halfway between building to 16psi. Only thing this only happened after changing the gearbox . Any ideas of what could be the problem.

[V28VX37]

Check your CAS: http://www.skylinesaustralia.com/forums/topic/326043-resolved-misfire-in-r34-gtt-rb25det-neo/

[Blackkers]

Just an update kind of really pissed that i changed the coilpacks and sparkplugs and the problem is still there. Car still randomly looses power when building boost or halfway between building to 16psi. Only thing this only happened after changing the gearbox . Any ideas of what could be the problem.

I was going to say factory intake pipe, but since you said it happens when building boost that wouldn't make sense.. Shame that you swapped out good coils and plugs to find the same problem.

All you changed was the GB? That shouldn't have an effect at all

[scotty nm35]

All it means is the fault is probably unrelated to the gearbox replacement, unless the knock sensor is still in use and the new clutch is triggering it due to noise?

[B-rice]

i used a known working CAS from a friend's car did pretty much the same thing even tested them by spinning it and the injectors ticked. One thing ive noticed is that when you if you accelerate lighty but super steady you can just get it to boost up to 16psi. Might just swap out the turbo and see if that helps. Will update

[B-rice]

Updating this thread for whoever might have the same problem. Hooked up a multimeter to all my sensors becasue it seems like a temperature related cut happening when the engine gets slightly warm. I found out that it was the MAP sensor, as soon as the boost starts building the voltage reading goes to zero. Looked at the temperature rating for the sensor and seems like it might have gotten too hot on the intake plenum and buggered it since it ranges from -20C to 105C.
http://www.ebay.com.au/itm/Pressure-sensor-Kit-3-5-bar-0-50-psi-MAP-oil-water-nitrous-/331004859478?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d116d5456&_uhb=1

[hypergear]

Nice to see its sorted. can't wait to see more power.

[ITS33]

I have the same problem in my gfs 34 gtt auto. Stock as with a cooler and exhaust any ideas?

[scotty nm35]

Updating this thread for whoever might have the same problem. Hooked up a multimeter to all my sensors becasue it seems like a temperature related cut happening when the engine gets slightly warm. I found out that it was the MAP sensor, as soon as the boost starts building the voltage reading goes to zero. Looked at the temperature rating for the sensor and seems like it might have gotten too hot on the intake plenum and buggered it since it ranges from -20C to 105C.

http://www.ebay.com.au/itm/Pressure-sensor-Kit-3-5-bar-0-50-psi-MAP-oil-water-nitrous-/331004859478?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d116d5456&_uhb=1

Good reason there not to run Ebay sensors for critical tuning jobs.

[B-rice]

Whats your recommendation. Seems like a AEM sensor.

[zebra]

Id buy one from haltech, link etc.

They've got runs on the board. If it buggers up its easier to exchange