i just put a 100 shot on my stock 94 z. it hits pretty hard off the line but in the upper rpm's it falls off bad. anybody had this problem before? it doesnt really miss, it almost acts like its starving for fuel but i've always heard that the factory pump is fine with a 100 WET shot? i actually put in the 50 shot and it wasnt as bad but still there. any help would be appreciated. thanks

 

Sounds like you just need to determine what's happening... is it shutting off the nitrous solenoid because a FPSS is triggering low pressure? Is the car running lean because your fuel pressure is low and you don't have a FPSS? Can you scan the O2's as it goes thru 4500rpm?

Dave

 

Dave, I though at WOT, O2 values don't matter? Maybe if he has scanning capability, he can take a look at his BLM's and see if there locking at 128 or if there really high indicating a lean condition.

 

At WOT, the O2 values aren't used by the PCM to do anything, but they certainly keep reading the O2 levels, and are what lots of folks use to measure rich or lean conditions. They don't have great resolution, but for example if you were running with only a fuel solenoid open, or only a nitrous solenoid open, they should absolutely show what's going on.

Dave

 

Nice info to know Dave. Never considered that one. I'm usually just peeking at my BLM's on the WOT runs. But then again, even though I was locking in at 128/128, it wasn't until I got to the dyno that I discovered that it was a tad on the rich side and didn't make full power until I dialed it in to 13.0:1.

Ken R. 95Z

 

BLMs get locked way before u hit 4500 rpm .. they get locked once u go into WOT mode which is around 70-80 % throttle depending on ur rpm .. so if ur AFR is within limits then, ur BLMs will stay at 128/128 thru ur rpm range ...

the O2s should be around 900-950+ at wot ... they wont show any accurate readings of ur wot AFR .. but if u see them in the 600 or 700 range u kNOW ur running lean as hell !!! or if their in the 1000+ range u probably have a fuel solienoid stuck open or something

 

when i checked the fuel pressure today it read about 36 at idle and 43 at wot. i think thats about right correct? im not sure what the problem is so im still searching. im not running a fpss so i know its not that. maybe ya'll can explain to me the real reason for the fpss. if the car looses fuel pressure it automatically shut off. if the fuel solenoid fails the fpss wont know it anyways cause its before it. maybe im wrong but i dont see the reason for one? thanks for all the suggestions.

 

That's not entirely true. There are many different ways you can use or hookup the fpss. You can place the fpss between the fuel solenoid and the nozzle/plate, and use the fpss to activate the nitrous solenoid only. If you're fuel solenoid died, this routing would close the the nitrous solenoid.

Personally, I dont use my fssp to deativate the nitrous. I've got a dummy light on the dash though. It goes out if the fp drops below 41psi. No gauge to monitor that way

 

so we figure out what the problem is?? cause ine did this.. but at 3200 all the way till 4500, then somethign just kicked in and i took off liek a bat outta hell...

 

well i did find a small rip inthe bottom of my intake boot today. some of the gas from the nitrous was leaking out. i guess that was it (or i hope anyways,well see). well i bought a new boot and an lt4 km while i was there. thanks for all the suggestions guys