Dyno/TPS Question

[Fubar231]

A buddy of mine w/ a 89 Supra had his tps unplugged because it was having errors. He said it would not downshift on his own. I was thinking, if i wanted to get the car dyno'd (cause im going to here soon), just unplug the tps and do a wot 3rd gear pull from like 2k so it doesnt downshift. Any input would be nice.

[funky_monkey58]

Do not do this.

[Jeeves]

No, the TPS is crucial for just about everything the car does.

[Fubar231]

Wonder why his car fuckin runs fine w/ the TPS unplugged. He still pulls on me, and still spins through 1st in a auto.

[Jeeves]

It'll fall back to a set of default "fail safe" maps. But without reading input from the TPS it can't tell when you're wide open throttle so it can't tell when to switch over to different boost maps, it can't tell when to kick down (automatics) it can't tell VTA (Variable Throttle Angle) (It's the reading that tells the ECU how fast the throttle plate is opening) which is a crucial measurement in acceleration and changing fuel curves, etc. Without the TPS it should/will be throwing a solid check engine light and it will basically be running on open loop only.

[Fubar231]

Originally Posted by Jeeves

It'll fall back to a set of default "fail safe" maps. But without reading input from the TPS it can't tell when you're wide open throttle so it can't tell when to switch over to different boost maps, it can't tell when to kick down (automatics) it can't tell VTA (Variable Throttle Angle) (It's the reading that tells the ECU how fast the throttle plate is opening) which is a crucial measurement in acceleration and changing fuel curvesm, etc. Without the TPS it should/will be throwing a solid check engine light and it will basically be running on open loop only.

Thanks for explaining it. I get it know. 1 Random OT question if anyone even looks at this again, one of my studs in my dp is broken and removed, and i havn't got a new one. Throwin code 21, im assuming its the broken stud and the o2 not being directly straight or something?

[Jeeves]

No. Code 21 happens when you O2 sensor is dead or is unplugged. You should (in theory) get a 25 or a 26 indicating that it went too lean or too rich and couldn't be fixed if the O2 sensor was working but couldn't be swung back to normal sensor range. You may want to verify that the wires for your O2 Sensor heater aren't broken either as a 21 can be caused by the Heater circuit failing.

[Fubar231]

Well it is EXTREMELY covered in carbon. Whats the cost of a new o2? Oh btw, i rewired my o2 so the wires are about 6-8 inches longer, and i have it run by my strut tower and over so it doesnt hover right over the turbo. i did rewire it correctly, used head shrink crimp connectors etc. I got this code when i put my new exhaust on and broke the o2 stud...

[Jeeves]

Originally Posted by Fubar231

Well it is EXTREMELY covered in carbon. Whats the cost of a new o2? Oh btw, i rewired my o2 so the wires are about 6-8 inches longer, and i have it run by my strut tower and over so it doesnt hover right over the turbo. i did rewire it correctly, used head shrink crimp connectors etc. I got this code when i put my new exhaust on and broke the o2 stud...

For O2 sensors if it throws a code it'll store it until you reset the codes. I'm assuming you've pulled the ground off the battery and let it reset for ~10 mins before (not really needed to be that long, but hey, pull it. Grab a cup of coffee, come back, it's really not that hard :-D) right?

If you go get a factory o2 sensor they're ridiculously priced (or were as of 2 years ago). However you can go here:
http://www.densoproducts.com
Now Select: Automotive, Toyota, 1990, Supra, L6-3.0L-7MGTE then "Oxygen Sensors" and it comes to $34.85. It'll require soldering (or crimping if you reallllly don't like soldering) or if you have the money the $100 option is the plug and play option.

MKIIITech also says (Now this is 2003 based info, so you'll wanna look around):

There isn't a plug-n-play O2 sensor offering for the 7M-GTE outside of Toyota. The trouble is the goofy 2 bolt flange that is used. Several sources offer that flange, but the cheapest I've found is Napa. This O2 sensor includes a threaded Toyota-style flange that will allow you to use any generic threaded O2 sensor on the stock elbow (or other DP w/the Toyota flange). You'll have to splice in your stock connector, but its not a big deal. Napa part number OS885, should cost $45.

and

Cheapest Bosch 3 Wire O2 sensor part number 13913, should be about $38. Threaded to fit in standard O2 sensor bung. NO FLANGE OR CONNECTOR INCLUDED.

For reference, back in '05 or '06, I purchased the OS885 at NAPA. It essentially converted the hole on the turbo elbow into a standard threaded O2 bung and allowed me to use any wideband or generic narrowband sensor there. So, if you can find that one (or if that first link ACTUALLY comes with the two bolt flange) I'd highly suggest picking it up.