y49crxsi

Well, this is driving me nuts. Ive got a d16y8, obd1, ubderdata, 10psi, maybe 11 or 12, but my boost gauge sits at 1psi when teh car is off, so its probably slightly off. Anyways, so far ive replaced my wires, plugs, step colder, gapped to .035, cap and rotor, and made sure all my connections were good. It still breaks up alot when Full throttle. Im tunign with uberdata, and when i think ive got it figured out, it gets worse, thats why i dont think its teh tune anymore. When it was running ok, without breaking up, it would be aroun 12.5 - 11.5 : 1. Then it would start breaking up in vtec. I just went out after screwing with the map alittle more, cleaning it up, and its alot worse. AFR's are unreadable when it breaks up, they ussually get really lean. BUt i know the map isnt running lean. Been using uber now for a while. Pretty comfortable with it.


So, question is, what can cause such bad misfiring other than the basic tuneup parts. Ive left the timing alone, kept it stock, put a .9 retard per pound on teh map to be conservative. Aany tips?


Oh, jsut to add, if i let off the throttle partially, it will clean up alot. Half throttle seems to boost great, and its a small turbo, so it pushes 10psi at half throttle easily.

projekteg

ummmmm, if your afr's are lean, then yes, it is your tune.

FooK

and gap down to .028 or .030 as well.

y49crxsi

well, i dont think its the map, because it wont break up in the same spot every time, its kinda random. And it seems to happen more once the car is warmed up. When it doesnt breakup my afr's are fine. Ill try closing the gap some.

vince_badaz

I had the same problem last year on my Z6 so you're not alone.
would be fine out of boost then would missfire in boost; this happened only at the end of summer also.

I haven't ran my car this year but I was thinking that my cap/rotor looks like crap so I will change that.
If you bought an non-Honda cap/rotor then this might be your problem since the metal tip on the jobber rotors isn't shielded like the oem ones (which could cause misfire ). Also, the gap on your plugs is big, most people go with .28-.30 as mentioned previously.

93turbo16

I think it is the plug gap.

y49crxsi

And yes, it was, fell like an idiot, took me so long to find that out. Runs great now, consitant afr's of 11.6 in full boost, which is now running at 13 psi, since i can actually give it full throttle. I need to take some feul out, but im waiting until i can figure out a decent and cheap usb cable for datalogging in uber. Everything i read says found cheap ebay cable, and then its nothing but people saying it didnt work. Will a digital cam usb cable work?

douspray

i had the same problem until i regapped the plugs to.028

sohc_mshue

a lot of people don't realize this. I had a problem tuning a prelude where the plugs were gapped too large. The car simply wouldn't accelerate past a certain point and would start breaking up real bad.

y49crxsi

yeah, i had mine gapped to .035, thinking that was enough, but ill be damned... lol. Iv been having this problem since i first did the setup, last year...