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Need help im stumped!

764 Views 1 Reply 2 Participants Last post by  sparksta
ok heres the problem, at full throttle my car would sputter at high rpm's. it wont even make it to redline. when i apply the throttle slowly i can get it up pretty high without sputtering (1st gear).when i do it with some other gears i get a lil bit of sputters.

ok so first i suspect boost leak. i retightened all the clamps and same thing. by the way im running a blow thru set up. correct if im wrong, but if it is a boost leak its only critical if the boost leak is after the maf? if it is a boost leak its somewhere on the manifold that i cant find, any ideas? oh and my idle sucks sometimes(it would die) and sometimes it fine. my vac is at 15psi

next i suspect the spark plugs. i am using ngk bcpr7es gapped at .8mm. maybe the spark plugs are too cold and gap to little? any advice?

im also suspecting the timing since i havent check the timing of the car. i dont really know what the procedures are, if you have to set it to timing mode or what not. also whats the base timing and what do you guys set your timing at?

also someone said that it might not be getting enough fuel. i am running a t3/t4 set up .60a/r intake and .63 a/r exhaust, im still using the stock 370cc injectors with safc2 at 8psi of boost.

also my engine temp is not working, it was working before now its not. dont know if that matters.

sorry for the long post but im stumped!

oh by the way this is a RB25det
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hmm i use ngk vpower sparkplugs (bkr5e11) gapped at .8mm, but as long as the ones you are running are for a 300zx tt then you should be fine ( some others might work but i know for sure that 300zx tt ones work )

as for timing and setting the idle, with a rb25 you d/c the throttle sensor ( its not the plug on the TPS its the plug thats on the like 5" peice of wire that connects to a plug below the TB). Then you adjust the rpms to 650 using the screw on the IAC valve, after you do that you plug back up the throttle sensor. The timing should be set to 15 degrees and when looking from the front of the car the timing marks go 0, 5, 10, 15, 20, 25, 30. You and advance and retard the timing by using the CAS, turning the CAS counter-clockwise will advance the timing and clockwise will retard the timing.

with the fuel deal you need to make sure your base fuel pressure is around 45 pounds without vacuum.

Also you might check into replacing the coolant senor because i know if the coolant sensor with 2 wires is bad then the motor will run like crap. I believe thats because the 2 wire coolant sensor, atleast on the rb20, is the one that goes to the ECU and if it doesnt know the temperature it will use a constant value and fatten the fuel curve. I think thats how it works but i'm not positive

Also since you are blowthru what is your BOV setup.

This is really all i can help you with as of now because you need to make sure that you have the base stuff set before you can further troubleshoot the problem. hope this helps
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