desperate for any help with ZX2 race car

[flyingtiger]

I am desperate for any help i have a 2000 zx2 that i race. The car sputters and looses speed when it gets warm which usually take 2 laps. most of the time it sputters in the in the middle of the turns and usually quits half way down the track, then it comes back to life with speed untill the middle of the next turn. i have had people tell me it sounds like a fuel issue, it sounds like its starving for fuel but then they say they dont know after i tell them it only does it when it get warm. i have a fuel cell instead of the stock tank, with an in the tank fuel pump. The tank is full when i go out to the track so its not the pick up tube coming out of the gas. The car has after market air intake but still has mass airflow sensor hooked up. Is there some sensor that is causing this problem. i have had 2 mechanics look at teh car and they just have no idea. They are just as lost as i am. I am desperate for help i have raced with this problem since the last 8 races. its aggrivating when you know the car has the potential to fly but i cant get the lead out of its butt. Any help greatly appreciated i hate to have to give up racing and send the car to the scrap yard.

[blue99fordzx2]

Does it throw any codes?

[Alwayssideways]

have you checked the cat? like a temp test?

[zxtwou2]

what kind of fuel pump did you use? our stock pumps are a PWM (pulse width modulated) returnless pump. this means it uses a drive module to make square wave pulses to speed up or slow down the pump. if you have a one speed "on all the time at one volume" pump, you'll need tuning, a fuel pressure regulator, and a return line. the car may be acting funny from too much or little fuel and the fuel pressure sensor on the rail is telling the pump to slow down/speed up and can't.

[Slikk726]

i had this same problem with my car when driving it down the highway, would be perfectly fine then when hot would all of a sudden die, then i pull over and it starts back up and goes. i was not getting any codes but turned out to be a crankshaft position sensor and the grounds that should be hooked up to 1 of the starter bolts wasn't hooked up, and when the motor would move forward the ground contact would be gone.

[flyingtiger]

It throws all kinds of codes. It's the same fuel pump I have ran for the last 2 1/2 had no problems until the last 3-4 races of last year that's when it first started. We changed throttle body and put a new throttle position sensor in it stopped for that race but it was also cold that night to. Took car to test and tune started sputtering. Not for sure about the cat/ temp test. I know one of the code it is throwing Is it's running lean, and there is a bunch more codes that it throws.

[Mimino]

It throws all kinds of codes. It's the same fuel pump I have ran for the last 2 1/2 had no problems until the last 3-4 races of last year that's when it first started. We changed throttle body and put a new throttle position sensor in it stopped for that race but it was also cold that night to. Took car to test and tune started sputtering. Not for sure about the cat/ temp test. I know one of the code it is throwing Is it's running lean, and there is a bunch more codes that it throws.

c'mon, son... go to autozone, print out the codes, post them here and fire your "mechanics."

[marc1974]

c'mon, son... go to autozone, print out the codes, post them here and fire your "mechanics."

That's great, lol

[mullman2002]

I'm having a very similar issue but no codes. As far as I can tell mine is due to an exhaust leak, but I don't know why it works until gets warmed up unless something to do with thermal expansion or some other scientific mumbo jumbo.

Question, do O2 sensors have a warm up period before they operate normally or anything like that? Thought I remembered seeing this somewhere.

[Slikk726]

I'm having a very similar issue but no codes. As far as I can tell mine is due to an exhaust leak, but I don't know why it works until gets warmed up unless something to do with thermal expansion or some other scientific mumbo jumbo.

Question, do O2 sensors have a warm up period before they operate normally or anything kilter that? Thought I remembered seeing this somewhere.

on my scanner the first bank is always reading values constantly, but the second bank doesn't start reading until 1-2mins after the car has started

[mullman2002]

on my scanner the first bank is always reading values constantly, but the second bank doesn't start reading until 1-2mins after the car has started

Is the first bank the front sensor, and 2nd the rear? Not sure what bank refers to.

[iceracer]

How's the foam in your fuel cell ?

[Slikk726]

The first is the one pre cat. Second is post cat

[mullman2002]

The first is the one pre cat. Second is post cat

Ok that's what I thought you meant. From what I could find online, it seems that O2 sensors need to warm up though I'm wondering if the sensitivity or how the ECM interprets the data changes.

edit.. just noticed the open loop, closed loop thing. That makes more sense now thanks.

[Alwayssideways]

the o2 sensors run in "loops" closed loop and open loop. In closed loops the engine runs off pre determined variables set in the ecu. Fixed fuel ratios timing and what not. Open loop takes signals from the o2 sensors. maf and iat to adjust fuel and timing.