hi guys!

so, i have high rpm hesitation since some time...

when i rev the car up to redline without boost, it will be fine... but when i'm boosting my car it's hesitating! most in the rpm range from 4000 - 5000 rpm...

i will check my TPS today, but i think it's in spec...
so, maybe it's boostcut?

i've stock intake, 3" dual Catback (Apex GT style but build dual), intact maincat and holed out precat...
my stock boostgauge climps up to 35

i know, when i'm hitting boostcut the ecu will shut down fuel delivery to my rear rotor... how can i verify this?

hoocking up an Voltmeter to my fuelpump? (is it switching from 12 to 8-9 Volt @ boostcut?)
or do i have to hoock up the Voltmeter on some ecupins? (injector pins?)

could it also be a damaged boost-sensor?

thx gus...

 

You mean overboost fuel cut, not boost cut. Fuel cut is not a hesitation, it's like a hitting a brick wall. All fuel is cut from the rear rotor and power drops to half instantly. It stays that way until boost drops or you lift your right foot.

You should not be trying to diagnose this with the stock boost gauge. You should've fitted a proper aftermarket one before doing and exhaust mods. You should go do this straight away. 350mmHg is only 6.8psi (fuel cut is at 8.6psi) but the stock gauge often reads low.

The fuel pump has nothing to do with fuel cut. The best way to watch what the injectors are doing is by measuring duty cycle. Connecting a DMM that can measure frequency and duty cycle to the rear primary injector ECU pin will tell you exactly what the injector's doing. Alternatively you could measure the voltage at the same ECU pin. At low duty cycle (engine idling) the voltage will read close to 12V and will drop as duty cycle increases. If the voltage suddenly jumps to 12V when the hestation occurs, the injector is being cut by the ECU.

 

ok, so i think its not fuelcut... because the car pulls on after this hesitation... no need to put the foot from the gas

what do you think is it? TPS? could it also be the boost sensor?

 

i have a new TPS in, its in PERFECT condition... 5,06kOhm@WOT
i
ve setted the TPS up with the 2led method... worked good...

but the hesitation haven't gone away

when the car starts bucking, and then pulls on, i hear a pop out from the exhaust... could it be ignition related? i get new plugs and wires @ monday or thursday... could this be the problem?

what
s about the boost sensor?

give me some input pls

 

Wait 'till the plugs and wires go in. In the mean time check the MAP sensor as per the FSM.