7mgte stumble HELP

[MA70-3.0GT]

That's half the problem with long running problems like this, you can end up running in circles if you forget what's been done. If something takes more than a few days to "nail" I like to start a sort of diary of what was tried, what readings of things were on a certain day, what happened when I did a certain thing/disconnected X sensor or Y plug & stuff like that... with any luck the computer will be able to get things straight anyhow, sounds like all the wiring should be OK... Hey here's a leftfield one, have you tried running it for a short time with the alternator unhooked (belt off not just unplugged)?

Like I say rather left of field and can only try this for one or two pulls from cold as the water pump would be down too, but I have heard of an electrically "noisy" alternator causing problems as it spun before...

[ccguy]

i have been working on it some more with a couple of toyota friends. we went back over everything i have checked. and found everything we checked to be in spec with the tsrm.
we hooked up a snap-on scan computer as well. it threw the code 32 (HAC) since i had it unplugged so i could drive it to town. the tool said that with the hac unplugged the ecu will shorten injector duration. so why would it run better with the shorter duration like when i have the hac unplugged? what trims how long the injectors open for? could it be like i previously thought, with a rich condition and flooding the cyl with too much fuel to burn with the amount of air?
i went over the tps again and i get all good signals from that at the ecu. the volts slowly increase when i open the throttle. the idl opens at slight throttle.

i would like to have another harness to try? might be a bad wire in the harness that test ok but wont transfer the continuity when it counts etc...????

[ccguy]

well hell.
i got a new oe style high flow toyota pump (AIRTEX #: E8119). but it flows more than the fpr can handle and it runs about 38psi on the rail and does not raise when the vac line to the fpr is removed. so ??? motor still runs the same...not good

i got a saab/audi bov still runs the same....

i tried putting a empty soda can in the exhaust tip to see if the exhaust was too free flowing and the turbo was spooling too fast/much.....ran the same.

shit. gonna try a few more things then maybe pull the turbo and check it out (even though it spools and does not make noise)???
then pull the entire harness and do a wire by wire recheck or rewire with new wire???

any more suggestions?

[ccguy]

well i pulled the motor harness and checked every wire. i found the shielded o2 wire was grounding to the inner wire. so i fixed that. everything else checked out good. so shit.
i unplugged the knock sensors at the ecu and it threw the code. and made no difference. i already did the rewire and that fixed the original wiring cel code.
as of today i started it and it was hard to get to fire. even ran crappier than normal. it still backfire POPs into the intake manifold when it is doing the hesitation.
also i unplugged the oil pressure wire to the ecu and it made no difference in how it ran. also my oil pressure is reading high or it at idle (so i might have a new oil pump in my future if i dont light this thing on fire only to piss on it to put it out
on this thread http://www.celicasupra.com/forums/sh...issues-bucking!
it kind of sounds like my shit and he replaced the afm with a maft and gm meter.......
i think i am going to try a new afm and see if that works???? i have tried 2 other used ones and to no avail.

could i go the maft rout or should i maybe go for the maft-pro???? i think my main problem is the tccs system being retarded somewhere in the mix.
the maft pro would basically replace my tccs ecu correct???

thanks for all the input.

[cre]

The MAF-T and the MAFT Pro and the MAFT Gen II are all made by the same developer. They're piggybacks which modulate the TCCS' input and output. The MAFT Pro and the MAFT GEN II are very feature packed and an excellent value for what they provide.. essentially standalone functionality on a piggy back budget. The MAFT Pro is about the same as the MAP ECU... They're all just piggy backs and none of them replaces the TCCS.

I've wondered for a long time now what the heck is up with your system... It's not right... to a degree that it feels like it should actually be obvious where the fault lies. I need to re-read through the whole saga to see what's already been done though before I just spend a couple hours repeating everything you've already done. But, not tonight.

[ccguy]

well been busy blah blah blah....
it is warming up here so i got a wideband o2 installed. here is the video.
i have a friend who is pushing that it is the turbo?? not 100% sure if i should go that rout yet.
here is the video with the wideband.
http://www.youtube.com/watch?v=pGTOPFjHf5Y
also when i go to start it now it is reluctant to start. i have to pump the throttle and it pops and barley starts from a cold start.
i have tried 3 used afms. autozone can not get the direct replacement for the supra but they can get the one fro a ls400. these are the same electronics except just the tube diameter correct? so i could try that and just swap the electronics onto my supra alum tube body?

[ccguy]

would the knock sensor throw a code of any kind if it is detecting knock when it is running?
i am almost certain it is the injector duration being cut from the ecu....since i can hook up a timing light and see where the ignition is when it is running. and it is not being cut or retarded. or the intake cam is out so the ign when it is going advanced it is sending spark out of time?? other than this retarded problem...
i cant hear any knock or ping. i am putting premium fuel in it tomorrow to see if that helps at all.

[cre]

Other than when warming up and at idle the ignition will almost always be advanced to one degree or another. If knock is detect no code is presented. The code is only presented if the ECU feels the sensor is damaged or providing erratic information (see: damaged).

A grounded OX signal isn't going to cause a severe shift in fueling. After a brief period the ECU would determine the signal to be faulty and go into open loop operation and ignore the sensor altogether.

The fuel pressure not increasing without vacuum indicates a bad FPR, vacuum leak or restriction from the couple times I've dealt with it. Try putting a vacuum pump on it and check the fuel pressure.

[ccguy]

i have a pressure gauge on the rail. with vac at idle it is at 34psi and without vac it is about 40. also when it is hesitating the fuel pressure is at 40 psi on the rail.

[ccguy]

no difference with premium fuel, valve timing is spot on with cams and crank
if i hook up a timing light (without the jumper in for setting base to 10deg) and slowly rev up the motor i can watch the crank mark move up to around ~35-40 (guesstimate) deg advance when i rev up the motor slowly.
at the beginning of the hesitation the ign advance will retard to around ~25deg or so.
no difference in the timing advance with a knock sensor unplugged.

i understand that the wideband O2 will read lean even if the injectors are spraying the correct fuel at the correct time, but if the ignition is not there and the combustion does not turn the O2 into CO2 then the wideband will read the amount of O2 in there and not read the unburnt fuel. i have a feeling that this is what is happening when the hesitation is going on. i just need to figure out why the ecu is retarding the timing???