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Discussion Starter #1
- Idle great when the car is cold (~750rpm)
- After driving it for a while and the car warmed up, it idle @ ~950rpm. (I even changed the Coolant temperature sensor with TOYOTA OEM one and it's still doing it, though i feel the car idle & drive smoother.)

- Even with LEXUS AFM, I Hit fuel cut if i go WOT in low gears (1st, 2nd, sometimes 3rd) (boost set @ around 15psi)

- Car runs rich (tailpipe & bumper is black) & backfire in first gear.
- RPM dropped below 500 and sometimes stall the car if i push in the clutch too fast while the car is in high rpm.

- While cruising & staying at a steady speed, the car will buck/jerk everytime i push OR let go of the gas pedal. In lower gears, it buck/jerk as if it's trying to take your head off.

- I noticed that the car moves extremely slow (much slower than before) until 3000rpm (turbo kicks in). I know it's not normal because it never does this before. No it's not the clutch or BHG, i've checked.

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- I got code 51 (yes, AC was off) & 34
- TPS is out of adjustment (because i took it off before)
- I can't change the timing to anything lower than 16 degrees.
- No Vaccum or Boost leak (i've checked) Vaccum is @ 20-21 in/hg @ idle. As for IC pipes, i've taken them out and checked and reinstall them with T-Bolts.
- Checked & tightened BOSCH Spec 110 recirculation valve
 

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Bump

Bump for me and the car tryin to stall grabbin hard clutch at high revs...
 

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***ified?
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o2 sensor? Leak in accordian hose? Did you check your intake manifold gaskets?
 

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Scratching and Sniffing
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Sounds like a bad boost leak to me. Check all your intercooler piping thoroughly. Mine was puzzling me for a couple of days till I checked the connector between the 3000 pipe and throttle body. Mine was split on the underside of the connector..hth.
 

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when this baby hits 88mph
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i had the same problem except for the idle bit.
searched everything and could not find the problem. actually discovered by accident when removing the fuel rail. one of the injector grommets that goes into the head blew out and made a massive boost leak.
however, the tps will cause all sorts of problems if not set right. id get that sorted first. might solve all your problems.
good luck!

dave
 

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Discussion Starter #6
VanSupra said:
Sounds like a bad boost leak to me. Check all your intercooler piping thoroughly. Mine was puzzling me for a couple of days till I checked the connector between the 3000 pipe and throttle body. Mine was split on the underside of the connector..hth.
i replaced my connector between the 3000pipe/throttle body with a Silicone one from (HighTempSilicone) & put 2 t-bolts on it.
 

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I also replaced the 3000 pipe to throttle connector IT WAS CRACKED go fig. :bigthumb: ...still tryin to stall. :dunno:
I can't find a boost leak...had to work...took it to shop...they can't spot a vaccum leak either...So it's the TPS ya think?
 

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I've been here forever.
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I would say that it is a boost leak from somewhere, check the intercooler for any sort of cracks as well as a loose hose. Also if you find something, make sure that you pull the battery to let the computer reset.
 

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Supra Fan
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WHat are you using for tuning? Without something like a safc2, your gonna be running rich. That can also help explain your loss in power and black bumper. The first thing id do too is get that tps adjusted correctly
 

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DO WORK!!
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if you are running rich like you say you are, I think you have found your problem......

you have all that unburnt fuel just sitting around and then it ignites at higher RPM's

also check all your grounds..... and i meen all of them. if you have a bad one then your problem may be there...... Just trust me.

Did you mess with the TPS prior to these problems?
 

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ODS
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Messed up fuel pressure regulator? You can go to a wrecking yard, and get one just to use as a test, or a friend of yours that owns a supra as well...

SMo'
 

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- Im guessing you have an after market BOV installed since your running 15 psi. if it is an atmospheric BOV then this may account for the stalling when you pushin the clutch fast. after if blows off, unmetered air enters the intake and the computer momentarily over corrects the fuel mixture.

- As for still hitting fuel cut with Lex AFM that is also normal. The Lex AFM doesn't eliminate fuel cut, it just raises fuel cut. So when your boost spikes in the lower gears you hit fuel cut.

- And once again i don't know what your mods are but if you have 550cc injectors installed you will run rich unless you have done something to tune your car. One easy thing to do is install an AFC and throw a wide ban on your car and lean it out where needed.

Scott
 

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A Happy Dad
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definately rich condition.. if you've ruled out boost leaks did you remove j-tube, it will help until you get safc aand yes you have to get the bov back into the intake or it will stall all the time
 

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Discussion Starter #14 (Edited)
did you 2 read my post? i have a bosch spec 110 RECIRCULATION valve.

what is boost spike btw?

- I have stock 440 cc injectors.
 

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Supra Fan
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Kroze said:
did you 2 read my post? i have a bosch spec 110 RECIRCULATION valve.

what is boost spike btw?

- I have stock 440 cc injectors.
YOU HAVE TO GO STEP BY STEP. FIRST THINGS FIRST. CALIBRATE YOUR TPS. THEN CHECK AND SET YOUR TIMING. Get rid of all codes. THen get yourself a piggyback and get it tuned. Its as simple as that. Your questions have been answered over and over but you just dont get it. :dunno:
 

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Kroze said:
did you 2 read my post? i have a bosch spec 110 RECIRCULATION valve.

what is boost spike btw?

- I have stock 440 cc injectors.
I missed the part where you said you had the recirc valve. Boost spike is where the boost surges past where you have it set at. You have yours set to 15 psi so you might see spikes up to 18 or so psi. And unless you have some way of monitering your air fuel ratio you probably shouldn't be running 15 psi on the stock 440s anyway. You may be rich at idle or when under 11-12 psi of boost but that doesn't mean your not leaning out at 15 psi.

Scott
 

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Hmm... Undo your CPS and spin it back one notch... set your timing to 10. Your car will get the pickup from below 3k RPM's in 1st/2nd/3rd again. And set your MBC to 13 not 15; even though fuel cut isn't bad for your car I wouldn't recommend hitting it everytime you go WOT.

The lungeing thing is the same on my car... The injectors shut off if you stop accelerating @ 1700 RPM and higher; so when you hit the gas the ECU sends signal to them again which is why it feels like it is bucking.

since you idle @ 950.. you should definately re-calibrate your TPS. Most people will tell you to use an OHM meter and the TSRM; however I like to go by feel/RPM.

You can do this by letting your car completely warm up. Go drive it for 10-15 minutes after it is warm. Loosen the screws on the TPS(hopefully you only have the top one in) and adjust until your idle drops to about 650. Now, it will get to 650 and then you have more play with the TPS but it stays there; what you need to do is set it to RIGHT when it changes to 650 and tighten and drive it real slow; barely pushing the gas. You will feel if you barely pussh the gas and hold it if the throttle body stays open or not; if not then you need to move it a little lower until it is nice and smooth. Now make sure not to set it to far; because then you will have play in the gas pedal.

Good luck; I have been watching your write-ups/installs and you seem to be on the same path as me. You are ahead of me with the afpr, but I have 550's lex boosting to 18 psi.. hehe
 

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Discussion Starter #19 (Edited)
Disced said:
Hmm... Undo your CPS and spin it back one notch... set your timing to 10. Your car will get the pickup from below 3k RPM's in 1st/2nd/3rd again. And set your MBC to 13 not 15; even though fuel cut isn't bad for your car I wouldn't recommend hitting it everytime you go WOT.

The lungeing thing is the same on my car... The injectors shut off if you stop accelerating @ 1700 RPM and higher; so when you hit the gas the ECU sends signal to them again which is why it feels like it is bucking.

since you idle @ 950.. you should definately re-calibrate your TPS. Most people will tell you to use an OHM meter and the TSRM; however I like to go by feel/RPM.

You can do this by letting your car completely warm up. Go drive it for 10-15 minutes after it is warm. Loosen the screws on the TPS(hopefully you only have the top one in) and adjust until your idle drops to about 650. Now, it will get to 650 and then you have more play with the TPS but it stays there; what you need to do is set it to RIGHT when it changes to 650 and tighten and drive it real slow; barely pushing the gas. You will feel if you barely pussh the gas and hold it if the throttle body stays open or not; if not then you need to move it a little lower until it is nice and smooth. Now make sure not to set it to far; because then you will have play in the gas pedal.

Good luck; I have been watching your write-ups/installs and you seem to be on the same path as me. You are ahead of me with the afpr, but I have 550's lex boosting to 18 psi.. hehe
Shit, when i took my tps out to clean it, i put it back with 2 screws. 1 on top and 1 on bottom. I guess i have to take everything off again including the ISC to adjust the TPS.

So what you're saying is that.

step 1: set the timing back to 10 degrees.
step 2: adjust the tps


I now know that the fuel cut @ WOT is becuase of the MBC. I'm boost spiking. I can boost just fine on 4&5th gear @ WOT all the way to 20 psi. But in lower gear, the boost just jump up way too fast and i hit fuel cut right away.

The bucking thing, you said that the injectors shut off @ 1700 rpm and above, and picked up again once you hit the gas, how do you minimize the bucking? My car is so bad that, if you're sitting back on the seat and i push or release the gas pedal on 2nd gear, your whole body will be thrown forward.

My Car: 90-T, here are the upgrades, anything that's not mentioned is stock.

Intake,
HKS Replica Downpipe, 3" piping & hi-flow cat.
MBC.

Lexus AFM
AFPR

Upgraded CT-26 (60-1 10deg clipped)
 

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Discussion Starter #20
could someone go into detail on how to remove the CPS and reinstall it so that i can adjust the timing back to 10degree?

right now, the lowest i can set the timing to is 15-16 degrees. wtf eh?
 
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