Nistune Forums

Sorry for so many forum post but the forum has been very helpful to me thus far and I don't really know where else to turn. I just got done tuning my car and everything seem to run right expect for the fact that when I let go of the gas too fast the car die, does anyone know how I can fix this issue? PS: When I tried to recirc my BOV by blocking it off the car still dies when I let off the gas too fast.

The car is a S14 240sx with a s14 blacktop.

is the maf too close to the turbo?

Its sorta close, the turbo is a T3 top mount and the maf is connected right to the inlet of the turbo,the intake and behind the filter.

Can You post a picture of MAF position?

I can't right now but if needed I can get pics tomorrow, the MAF is about 7-9 inches away from the turbo.

Is the speedo reading in nistune working correctly?

Yes

Is the TPS working correctly? (home position, voltage output etc)
Does the ECU perform Fuel Cut as expected in reference to the fuel cut tables?
Does the exhaust reading from the o2 sensor display a lean condition when you close throttle?
Is the idle speed set correctly? (mechanically set below minimum clearance)
Is the idle circuit reacting fast enough? (sticking valve or motor plunger)
Does the engine go through oil quickly? (turbo or valve stem seals leaking etc)

What size injectors are fitted?

Is the TPS working correctly? (home position, voltage output etc) im going to try to reposition the TPS today
Does the ECU perform Fuel Cut as expected in reference to the fuel cut tables? Yes
Does the exhaust reading from the o2 sensor display a lean condition when you close throttle? Yes
Is the idle speed set correctly? (mechanically set below minimum clearance) Yes
Is the idle circuit reacting fast enough? (sticking valve or motor plunger) How do I test this?
Does the engine go through oil quickly? (turbo or valve stem seals leaking etc) I can't really say since the engine was just install, but I would have to say yes when it was running rich, but more okay now.

What size injectors are fitted? SARD 550 cc
UPDATE: I tried to reposition the TPS today, but I can't get a clear reading, it fluctuate randomly and I can't get a clear reading. Even when the motor is off the TPS just fluctuate up and down. Is this normal for an SR motor? or is my sensor fuck up.

Yeah shouldnt be fluctuating like that. If you change tuner mode to stream mode and without engine running (ignition on) are you still seeing it?

It should be a steady voltage except when TPS itself is moving

HTrang wrote:PS: When I tried to recirc my BOV by blocking it off the car still dies when I let off the gas too fast.

Wouldn't that just cause the pressurized air to surge back through the turbo and be metered again?

on the stock throttle body the fast idle cam will make the voltage change.. tps adjustments should only be done when engine is at operating temp ~ 80 deg..

chris2712au wrote:on the stock throttle body the fast idle cam will make the voltage change.. tps adjustments should only be done when engine is at operating temp ~ 80 deg..

I did as Matt suggested, and the TPS voltage was just jumpng all over the place even when the engine is off and we are just sitting there doing nothing, are you saying that this is normal? I have already ordered a new TB and TPS and I will try to figure out what's wrong this weekend.

What if you disconnect the TPS?

Something really strange is going on here. It shouldnt be doing that at all

Can you get a log file in stream mode and post it here for us to see?

I just replace and reposition the TPS. It seem to be working perfectly normal now, no jump or weird spike, but my original problem still remain, every time I gas the car pass 3-4k rpm the cars bog down dies if I don't catch it fast enough. I have no idea what to do now, any more suggestion?