poor fuel mileage with zzp 1.0 pcm

[99GPGTP]

heres the story. the transmission went out in my car 2 years ago. i just recently for it fixed.while the car sat the fuel pump went bad, i installed a AEM 320lph pump. i put new oil pan and timing cover gaskets on my motor while engine was out. Installed a ported m90 housing. and a zzp 1.0 pcm. car was only getting 13-14mpg around town. and 15-17 on hwy. which is almost half of what it used to get. i changed the injectors, o2s, tried a new mass air from a friends car. installed an adjustable fpr. even went back to my stock m90 housing. none of these changes made a difference. 3 days ago i put my stock pcm back in my car and the fuel mileage went back to 28-32mpg on hwy and 20-23mpg around town.

has anyone else run in to this issue before or can tell me what i need to do to get my mileage back up with the zzp 1.0 pcm

[Reptile]

They've probably done something in the programming. I doubt you're gonna get good mileage out of the ZZP one.

[SgtMarshal]

I ran a zzp pcm on my first grand prix and still got reasonable gas mileage. not sure why yours would be different.

[Reptile]

They're hit and miss with them. I've seen some really goofy stuff in the programming before.

[99GPGTP]

so i need to just get the hp tuners and tune it my self?

[Reptile]

That or you can get another PCM

[Reptile]

You didn't have any gearing changes in the transmission while you had it rebuilt, did you?

[Uno99]

My old ZZP 1.0 tune was extremely fat as well. Especially on cold startup and idle. Turned my good lookin tips all black is was so bad.

[99GPGTP]

Trans has same gearing. Did add a 2500 stall. But when in lockup it shouldn't matter. I wonder if i would hurt fuel mileage by putting the ported m90 back on.

[99GPGTP]

miles calculation been with a calculator and tip adometer and gallons in

[coolone]

Maybe they avoid leaning out by dumping fuel and killing the efficiency? You've modded, are you monitoring? What's your afr?

[99GPGTP]

Maybe they avoid leaning out by dumping fuel and killing the efficiency? You've modded, are you monitoring? What's your afr?

No afr gauge yet. That's the next mod i will do. But i have 0 kr with either pcm

[DanPrixGTP]

I had a ZZP "Custom" can tune for my car. My LTFT's were ALL over the place, I mean +/- 17, it was insane, and my AEM Wideband would peg out at 10.0 at WOT.

I have heard their tunes run rich, and my Wideband would clarify that - but only at WOT. Not sure if this matters, but my cruise timing on the highway with the ZZP Tune was roughly at 20* - not sure what stock is, though.

[99GPGTP]

I will recheck my ltft. Last i saw they were up to +25 at idle

[DanPrixGTP]

I will recheck my ltft. Last i saw they were up to +25 at idle

Same here with ZZPoo tune.

If you get 0* KR with your stock PCM, why bother using the ZZP one? Try to get an in-car tune, get a tune from Reptile (on this forum), or get a tune from Overkill Motorsports.

[Uno99]

Yep go with Retile or overkill i think overkill gives a $50 discount if you have some other companies tune and you go will one of theirs.

[Reptile]

If you send me the zzp one I'll cut you a deal, since I won't have to source one.

[Uno99]

Do it ^^^^^^^^^^^^^^

[99GPGTP]

I'm driving 70mph cruise set. And my ltft is -11 and stft is 1 front o2 is reading 500-900mv. Baro reading 14.1psi
map @ 4.4-6psi

[99GPGTP]

Changed mass air and front o2 sensor. No change in fuel mileage. Still averaging 18mpg. Is the aem 320lph pump just way to much for my setup?