dyno pain

[undercoverz-28]

if you remember i recently sent off to have my '96 tuned for my first mail order tune ever. i got i back about a month and a half ago. lets just say, i thought it felt a bit...........different.

2621


2622

i think i was lucky not to blow the motor. the pervious owner dyno'd the car at 276. i have not lost hope in the process or the person who did the tune. from what i understand, no matter how much tuning experience someone has its still an educated guess, so i'm still hopeful. i guess i'll be sending the ECU back, with some good information this time, to be tuned again, still waiting to hear exactly what to do but thats my guss. i did hit 360 tq though on my third pull :finger: hopefully i'll be back on the dyno before the month is out (theres a special right now this month).

[Fastbird]

What's the setup??? Fuel system in good standing??? I ask because both those graphs start going lean at just about the same point at around 3500 RPM on both. You maintaining pressure all the way up?

[undercoverz-28]

setup is K&N CAI, Pacesetter LT's, o2 delete, egr delete, 160 t-stat. i think thats all that would affect hp #'s. the fuel filter has been replaced recently so its not clogged. physically i guess next step would be the pressure at the block but what, other than the obvious (the pump), would cause that. theres no leaks or anything. so like a clogged or bad injector(s)? and i thought fuel pumps either worked or didnt. is there an dying stage for pumps? to me its lean from the get go. 13.5:1 to 14:1 til 3.7k rpms then it just gets worse. i thought optimal af was high 12's at lower rpms and low 13's in higher rpms. to me if it were a physical issue it would still have good af at low rpm (pre 3k) because theres no load on the fuel system. just my thinking though. any thoughts on things to physically check are appreciated. thanks.

[undercoverz-28]

oh i was told while dynoing i had a small exhaust leak but its so slight i never heard it while in the car on the dyno or while driving. so i dont think it would skew it that much.

[Z28pr0jekt]

Check and see if your fuel pressure regulator is bad, pull off the vac line going to it and if it smells like fuel or has fuel in it at all, chances are you need a new regulator

[joelster]

Why on earth would you delete the O2's? The O2's are critical for running in closed loop mode. If the O2's detect a lean condition the fuel will be adjusted.

[Z28pr0jekt]

Why on earth would you delete the O2's? The O2's are critical for running in closed loop mode. If the O2's detect a lean condition the fuel will be adjusted.
Maybe he just means the rear O2s?

but yea I didn't catch that.. not good if they were all Deleted

[undercoverz-28]

lol ya just the rears. his suggestions were the MAF, vacuume leaks, loose connection in the elbow between the MAF and the TB, fuel filter and directly check the pressure. 3 out the 5 i'm 99% sure are good but will get another look and the filter was replaced last july so i'll hit that then check the pressure and see where i stand. funess.

[undercoverz-28]

well, physically everything appears to be in order so hopefully i'll have another dyno post here soon with a new tune.