R33 Gtst S2 Problem When Boost Over 5000 Rpm

[janno40]

Hi all,

firstly i am new here i am jan from germany , 29 years old and i have to skyline,s in my garage A R33 GTST spec 2 and a R34 GTT. i am a truck mechanic .

my englisch is not perfect but i am doing my best ,

so i have a problem with my r33 GTST spec 2 i imported from japan !

i hope some people here can help me as the forum in australia is definatly the best in the world !

so to my problem,

the car runs fine under 5000 RPM i can boost it and it runs exactly fine trough 5000 RPM , when it exaclty hit 5000 RPMS it stops like it don,t inject anymore fuel !

if i run it wit under pressure so under 0 bar boost then i can run it perfectly over 5000 rpm until it hit the limiter,

so the problem is only when the boost is there ! so if i boost it a little over 0 bar overboost then the problem is there if i run it uner 0 bar then i can rev it perfectly until the red zone !

if i pull full boost it runs fine until 5000 rpm and then it don,t accelarate any more , it don,t react ont the throttle when i putt my foot from the gas pedal and it is under 5000 rpm i can accelerate again,

so after 5000 rpm with boost it doe nothing no schock , no acceleration , i now when it shock then it musst the coilpacks but he don,t schock or vibrate the engine do nothing above 5000 RPM , so it must stop the fuel injection or the ignition,

hope somebody can help me here,

i already cleaned the afm , and check the fault codes and there was no fault codes !

hope somebody can help me

greets janno

[paulr33]

what are you using for boost control

the stock ecu has a ton of protection so that if you increase boost, it basically dumps all the timing to protect itself

[janno40]

Car drives on stock boost so no modifications only a exhaust system,

but the problem is also there wit only a little bit of boost and over 5000 rpm so it can,t be protection from the stock ecu for overboosting,

but thanks for you,re time

[Torques]

Hi ..

So standard boost, no boost controller ..? Are you sure?

Is it still the standard ECU in there?

Did you do a reset of the ECU?

(unhook the battery)

Did the car always behave like this?

From what you say it sounds very much like fuel cut from the ECU ..

It does this when the load reaches a certain limit.

But unless you run around 12-14PSI of boost the ECU will not cut.

Cheers ..

Car drives on stock boost so no modifications only a exhaust system,

but the problem is also there wit only a little bit of boost and over 5000 rpm so it can,t be protection from the stock ecu for overboosting,

but thanks for you,re time

Edited October 12, 2011 by Torques

[janno40]

Thanks for you,re reply torques,

the ecu must be standard,

the engine don,t accelerate after 5000 RPM with only a little bit boost 0,2 -0,3 bar ! so it can,t be fuel cut , also by fuel cut the engine schocked , stopped ignition and after he will accelerate again,

if i hit my car over 5000 RPM with trottle full down then the engine doesn,t accelerate anymore, if i keep the throtlle down than the car also don,t accelerate under 5000 RPM i need to putt my foot from the gas and if the engine is under 5000 RPM i can,t accelerate again.

it is weird because it only does with a little bit boost and over 5000 RPM,

today i have changed the fuel pump but the problem is still there,

so what i have done until yet: -cleaning AFM

- change fuel pump

- check for leakage on tubopressure circuit

- change tubro solenoid

but this al does not help,

hope somebode can help me .

the one wit the golden tip will get money for a pallet of beer

greets janno

[janno40]

and yes i recet the ecu by pull the batterie away,

this problem was there since i bought the car

greets jan

[DVS JEZ]

Try disconnecting the turbo boost solenoid and just running the hose from the wastegate to the intercooler pipe or wherever your hose comes from.

Keep an eye on the boost level

[The Bogan]

Plug gap, coils, fuel pump, fuel filter ?

[chocco]

Inspect your CAS cause if the shaft has slop in it the timing will be out.

[defari]

lol coilpacks?

[Torques]

Thanks for you,re reply torques,

if i hit my car over 5000 RPM with trottle full down then the engine doesn,t accelerate anymore, if i keep the throtlle down than the car also don,t accelerate under 5000 RPM i need to putt my foot from the gas and if the engine is under 5000 RPM i can,t accelerate again.

Hi!

That's excatly the behavior when the ECU cuts the fuel.

The ECU has an internal value for LOAD, if that LOAD is reached it will cut the fuel UNTIL LOAD goes BELOW a certain threshold.

(google for TP load limit nissan)

However, as you say, it is strange that the cut appears also with low boost.

Check your ECU and find out what's in there.

(just to be sure)

Did the car always do this?

[janno40]

Hello,

thanks for all the answers,

the car does it since i have it so it have done it all the way since it is my car,

i will change the ecu with one of my friends R33 spec 2,

also i will put new plus in and new coilpacks but i now when the coils are bad it schocks by 5000 RPM but my car don,t schock it don,t accelerrate anymore,

if have already tried to disconnect the solenoid but it is still the same,

greets jan

[Tangles]

Hi janno from Germany - great to have you here with us on SAU.

Firstly, take out the ECU (passenger kick panel), undo the lid and make sure that the ecu itself hasnt been "chipped" - it may have an aftermarket eprom ecu chip installed.

Reason I say this is I too have had a similar situation to yours.

I am running a remap eprom chip in the stock ecu of my 1997 Series1 C34 Stagea auto awd wagon, plus a piggyback computer to further finetune the setup (was a mailorder tune from sau user Toshi who does ecu eprom chip tunes). The piggyback is AEM Fic/8, an american ecu similar to Greddy Emanage Ultimate piggyback ecu.

I had a cut like you describe at around 6500rpm. To get around it I installed a Fuel Cut Defender and we tuned around it via the FCD and aftermarket piggyback computer on the dyno. Between 6200-6500rpm, depending on conditions (ie hot or cold weather, brand of fuel, slightly up or down hill) it would splutter like you describe. Was a total loss of power, felt like a fueling issue but 100% positive it was a LOAD issue as Torques descibes above.

After tuning around this area with the piggyback ecu, using the fuel cut defender to clamp the air flow metre signal at this rpm point, we were finally able to run the rpm out past 7000rpm to redline. Caution must be taken though when using a fuel cut defender (FCD) because if the tune isnt great you could damage your engine. I blew the ringlands of piston #5 on the track soon after using the FCD method to get around this load issue - however I damaged the engine previously at a track day by boiling the oil/water and most likely creating cracks in the ringlands at this time, so it was only a matter of time & a heavy leadfoot at the track before it let go once and for all.

You may wish to try another Air Flow Metre as your current AFM may be starting to play up - in the FAQ section here on SAU there is a guide on how to fix cracked solder joints within the air flow metre. As a last resort a Fuel Cut Defender might be of assistance, but would require careful setup on a dyno, and to be honest should be viewed as a last resort.