7mgte stumble HELP

[ccguy]

thanks for the reply. yes i have tired another ecu. i have a spare. the tps has been rewired with new wire so i dont think it is that unfortunately.
but yea it seems like the afm is telling the ecu it is taking more air than it actually is.
or the tps is telling the ecu that it is floored. this would explain why the motor acts like it is being floored under load ( with the throttle body barely cracked and the motor continuing to rise in rpm like i am flooring it.
also while having the throttle barely cracked and rpm like 3000 the vacuum will be at like 0 but i can hear the waste gate open and the woooosh from that. but it is not boosting.
i really wish i had someone within a 4 hr drive that knew stuff about this motor or had a supra to help diagnose the problem.
but i will look back and check out what you suggested. thanks

[MA70-3.0GT]

Yeah I wish I was able to get over to have a proper look into it, chewy electrical/electronic faults are well, maybe not my forte, but I love working through them for some reason (must be sick in the head lol) & I'd have got my '89 round for some swap-tests too

I've found even new rewire jobs can cause issues sometimes, would def be worth checking for any kind of short at the ECU pins for those TPS terminals if only to rule them out 100%. Also, what sort of wire was used for the rewiring you did? I don't know how sensitive the Toyota ECU is to RF or EM interference but could be worth making the TPS wires twisted pairs &/or wrapping them in foil to eliminate any possible outside interference from other nearby circuits seeing as they deal with fairly low voltages. Obviously you know the knock sensors are very very sensitive to this sort of issue & their wiring should be decent shielded/twisted stuff too (would imagine they're OK anyhow as interference there seems to throw a code 52 and you don't have that at any time right?) Depending how much of a pain it would be, I'd say maybe try to isolate all the low voltage sensor signals from the rest of the loom or at least any sensor wiring that was re-hashed for the transplant.

Another quick check on the TPS & wiring is to block the throttle open slightly, switch on the ignition & run a diag check. Should throw a 51 for no IDL signal at power up. Maybe covering old ground here but then I didn't notice if this check was done in previous posts... Damn I wanna look at this, it's screaming fuel cut at me....

[ccguy]

thanks for the response. i used new automotive grade 16 gauge napa wire. and i have tested the tps wires at the ecu on ohms and volts.
i had a 52 code when i first got it running, i rewired the knock sensors with some shielded coax like the write up online.
yea i get the code 51 with the jumper in and opening the throttle at the beginning and the idl opens when testing the tps wires.
the factory tps wires do not have shielding on them. only the cps, o2, knock have a shielded ground around them.
i have preformed the fuel cut test like in the tsrm and the problem i have acts different in person than the test acts.
but i have never heard fuel cut in person so it is hard to compare it to it.
i am going to have a friend come over and help me in the next few weeks. he has a snap on super computer diagnosis tool, hopefully it can read frequency and maybe even o2 like a wideband?

it is getting hard to remember all of the stuff i have tried. between the wiring checks, sensor/parts checks, and troubleshooting.
i will look into the tps and the wiring again.
i hope i can check and see what the afm reads with the hac hooked up and with it unhooked and see what changes.
i originally thought it was the tps but have not been able to prove it was the tps so far.

i enjoy wiring motor swaps as well and diagnosis. but this one is killing me. it has been over a year.
i tried checking the vf signal at the diag port but i dont fully understand where to go with the results i get.
i have wired multiple motor swaps from tacoma 3.4s to chevy 4.3s to lexus v8 to ford i6s. so i am the guy people go to for wiring problems but i have not been able to figure this one out yet.......

[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.