massive run rich problem-HELLLPPPP
 

Hi all, Here's the history and the problem.
89 supra, red, targa, gte.
rebuilt motor about 7k miles and 4 years ago.
Uncle drove it and the tentioner loosened...
jumped teeth=bent valves. He bought a 97 tt and gave
this one to me. I have been the sole mechanic since we bought it in 92.
sat 3 years in back yard while i collected parts, rebuilt head, ect.
inside had a leak during this time and fungus galore.

ok, i got it all back together. started it up, idle problems.
iac motor sludged. iac cleaned. it idles beautifiul.
drive it. doesn't develop full power and misses above 4-5k.
drivable, but not what it should be.

Anywheres between 10 min to an hour, all of a sudden give it gas and
it immediately stumbles, falls flat, black smoke out the back, and the
chek engine light comes on. from then on, if you give even an 1/4 "
of gas pedal, car just sits there. very lightly feathering the gas and i can
coax it to move. I need to keep the rpms as high as i can and release gas apon shift or it stumbles all over again. It will stay like this till it sets overnight. I have replaced the maf and the tps. the cobe, btw is 41.
I have tested the tps and it checks out.

total frustration.
any ideas?

thanks
rodster

my first thought is that from sitting for all that time, the turbo went dry, wasnt properly primed after you got it running and after a few more miles the turbo siezed.


Its just a guess though

run a diagnostic (found in the faq section)
fix any boost leaks

that's ya first thing you need to do, could even be knock sensor problem as that will richen fuel & retard timing something silly
if your check engine light is coming on there will be codes stored

and it is highly unlikely any valves were bent as the 7m is a non interference engine :)

massive run rich, ect...
 

Thanks supra_gurl, I'll check that out soon.

First off, the turbo spools up nice. I had a dummy on there after the rebuild and this one was installed when the valves were replaced. I'm only getting 5-6 # of boost, but it/s not 0.

Second...
I still have the 6 bent valves from the belt slip. the 7m IS an
interference engine. if the belt were to break while the engine is spinning, i imagine the valves would be pounded to hamburg and the pistons would be ruined. I had to re-machine the valve cutouts in the piston tops for only 2 teeth worth of belt slip. Another tooth worth and i would have replaced 12 valves, whereas the exhaust cam is set in such a way that one set openes just before the other. only reason i can see why only 6 were bent , and only just barely. but yea... find an old supra in the boneyard, remove the timing belt, then slowly turn the motor by hand. i guarantee the motor will stop abruptly.

3rd. it does throw a code when it goes to hell. code (note cobe) 41.
tps sensor circuit. I will do more testing this weekend.

thanks for the ideas... keep em comming...
Peace
Rodster

the 7mgte is not an interference engine, i can post up many many sites which will tell you this same thing
when i bought my car the idiots that used to own it forgot to bolt up the exhaust cam pulley and the timing had jumped 4 teeth
i used the very same engine and just put another belt on and got a bolt and new pulley and put it all back together compression was an even 150ish across the board
either the head or the deck of the block has been severly surfaced to become interference, did you ever do a compression check on it?
what size hg did it have?

a boost leak would not necessarily mean you get no boost, when i had a boost leak (off the turbo going to intercooler) i would reach 6psi then hit fuel cut violently
fix that boost leak still another one in the system but i could now reach 8psi

have you reset the ecu to get rid of the tps code?