7mgte stumble HELP

[cre]

Try using a voltage divider/resistor network to bypass the HAC and see how the engine operates with a static signal. You'll want between 3 and 3.5v for sealevel.

See here for some more detailed instruction.

[ccguy]

so my hac is reading 3.04 volts and i am at 6500 ft elevation.
would that sound about right for what it should be?
i am going to do another video and show you guys what i mean by when it acts worse with the hac connected.

[ccguy]

there is NO difference if i unplug the O2 sensor. nothing.....?
if i unplug the tps or the afm it wont run for crap.

here is a video driving. notice at the end where it accels when i barely have the throttle cracked.....could that be my iacv sucking in air past the tb?
when i say it "bucks" it feels like as if you would pop the clutch or wot then let off. feels like it is going to break a u joint or motor mount

http://www.youtube.com/watch?v=eDLr4...ature=youtu.be

also i was thinking about the hac. as the altitude gets higher it tells the ecu there is less o2 so it reduces the amount of fuel sprayed (right?) so in theory if it is a lean fuel issue pluggin in the hac would farther confirm that due to it cutting the amount to be sprayed.
hopefully the fuel pressure gauge will get here within the next 2 days.
with the pressure gauge could i put it on before the fuel rail? basically just before the dampener or should i try it on the rail like off of the cold start inj?
i will probably try both just to see how it fluctuates

[cre]

I'm stuck typing one-handed for a while so this will be brief.

If you supply the HAC input with a static signal for sea level and the car runs better the it's likely running a bit lean normally. HOWEVER, leaning out or enrichineng can also compensate for other issues such as bad timing (mech and ign). Just unplugging the HAC may put the ECU in a failsafe mode (just as far as the sensor in question's input is concerned) causing the ECU to add a little more fuel on top of the trim for sealevel. Use a resistor network to provide the ECU a true sealevel signal, it's only a matter of sticking two resistors in the harness connector.

O2 sensor won't make any difference except for after warm starts with it disconnected (you'll run rich) and during closed loop operation at normal operating temp.

Before the damper is the fuel rail. If you're referring to the return then no, that's not a pressurized hose. Yes, use the CSI's port on the rail.

Have you tried another AFM?

[ccguy]

i installed a fuel pressure gauge. with just the walbro running the fuel pressure before the dampener is crazy bouncy like 32-36. with both of the pumps running (walbro and in-tank pump) the constant pressure is 38 psi. and it goes up to 42 ish with higher rpms.
with just the intank pump running the pressure is constant 34 psi and up to 40 when revved.

yes, i have swapped out the afm for another and it acts the same. i wish i could swap it out for a tacoma inline afm (since i have one and they are a lot less touchy.
it sucks because i have not seen even 1 mk3 supra in my town of 30,000 people. would be nice if i did so i could invite them over for dinner and swap some parts out.....shit

[cre]

Ok, so not the pump(s). The irregular pressure with one of the pumps off isn't surprising... I wouldn't leave them both in place.

Personally, I'd get a wideband and a MAFT Pro, install a GM IAT and MAP sensor, delete the KVAFM and HAC altogether and then see how well you can tune it.

I'll re-read the thread later to see what we've missed or what is still suspect.

[ccguy]

thanks. i turned off the walbro and am just running the intank pump for the steady psi.

i just got done at checking the voltage at each ecu terminal at idle and when the problem starts. the only thing that changes drastically is the egr output to the vsv. it goes from 1.11v to 14v at 2200 rpm when the hesitation starts.

i am going to try and read a bunch on the egr system and see what i can find.

i am going to try and get this done SOON. i need this truck for my elk hunt that starts in a week. otherwise i have to do a ton of work on my ford (replace ball joints, starter, and flywheel) by then.