i've been working on a tahoe and i have the tune dialed in pretty good. but the damn thing has the weirdest issue i've ever seen. sitting at a dead stop if you just stuff the pedal it will buck and fart and just fall on its face then a second later it picks up and slams you back. WTF could be causing this? the closed voltage is .65 IIRC and it reads full closed on the logger. i did the tps reset thing also. can it be too much timing? i had added some down low in that area when i first started the tune. then i pulled a little over half of it back out. should i pull more out?

mods: heads/cam/TBSS mani/edelbrock 90mm/ long tubes.

 

Some body has to have some insight. Something is not right this truck is slow as ****. Just to see how it's doing I had my wife drive it and race me in her car. It's a 94 civic hatch with a b16a that is bone stock. Just an intake and exhaust nothing else. Even stock exhaust manifold. And I just stomped the **** out of this tahoe over and over. I even let her get a head start. It's just not making power. It should be able to take her car no problem I would assume. I'm very disappointed in this tahoe.

 

When you do that does the actual AFR go extremely lean or rich? If so i would check out the Transient Fueling (Stomp). if you roll into the throttle does it do it?

 

also what does your Injector pulse width do at that condition?

 

When I drive the truck the throttle seems fine when you take off normal driving but I'm light footed. I'll have to look at the tune but it seems like timing was staying kinda high but map was shooting up kinda fast. I was thinking maybe the tps wasn't low enough to set the correct idle parameters. But it reads zero on the logger. As far as WOT goes it's out of fuel. The Maf reads up to 42lb at the top end. And the Injectors go to 110%. But that not until say 5000 and up when it starts to get above 90% duty cycle. Below that it has enough fuel but doesn't seem to pull like it should. I wanna say the heads are 63cc's with stock pistons. Could it be the compression is down enough to require more timing that I'm giving it? It's at 26 and up to 28 on the top end. It kinda slopes with rpm.

 

But the o2's are in the low 900's at wot. He is suppose to get a wideband for the damn thing. It went from a good build with good money backin it to "hey I got a devorce and I'm low on cash" build. So he has to save for a wideband and some 42lb injectors. So I think until then I may be stuck with it as far as wot. But I can still get the take off fixed. He is a half throttle green light guy. And it will damn near die when he does it. I could hear a ping pop before so I figured it was too much timing. But even with factory timing it would hesitate on take off.

 

Can you post a log and if you can log the injector pulse width or duty cycle.

 

Yep I can do that. It always logs dutycycle and trims.

 

http://www.hptuners.com/forum/showthread.php?t=34242. There is the link to my thread on hpt that has some logs. I'll post the latest in a bit.

 

ok i have a screen shot of this stupid thing. i don't have a clue wtf it is. i added fuel and all kinds of stuff it just randomly bogs pops and goes. i almost got hit a couple of times.