'94 SC400 TPS part #?
09-01-14, 03:41 PM
#1
'94 SC400 TPS part #?
I'm thinking it's worth trying a replacement TPS for my '94 SC400, as I still haven't managed to set it properly. I can never find a spot within the adjustment range that meets both feeler gauge criteria, and I keep getting the light throttle ~40 mph bucking hesitation returning after I try readjusting it. That bucking goes away if I disconnect the TPS, so I'm 99% positive it's the culprit, either its adjustment or it being defective.
Anyway, my TPS is part #89452-33010. I was about to order a replacement for that, then noticed that most such part numbers are listed as being for the SC300. There are exceptions, though. RockAuto lists #89452-50010, #89452-50020, and #TPS4179 as being the correct parts for '92-97 SC400s. I've seen a few other variations, as well.
Are they all the same thing, or are there subtle differences? If I were to match wire colors for the ones with the pigtail still on them, would that be reliable? I'm wondering if a previous owner put a different TPS on my car and that's part of the problem, but I can't find a reliable listing of what's the correct number.
Anyway, my TPS is part #89452-33010. I was about to order a replacement for that, then noticed that most such part numbers are listed as being for the SC300. There are exceptions, though. RockAuto lists #89452-50010, #89452-50020, and #TPS4179 as being the correct parts for '92-97 SC400s. I've seen a few other variations, as well.
Are they all the same thing, or are there subtle differences? If I were to match wire colors for the ones with the pigtail still on them, would that be reliable? I'm wondering if a previous owner put a different TPS on my car and that's part of the problem, but I can't find a reliable listing of what's the correct number.
09-01-14, 05:50 PM
#2
I found some possible answers, but feel reassured in my uncertainty by equal confusion on the part of others.
https://www.clublexus.com/forums/per...ps-sensor.html
So, my 33010 is a newer version of 12050 and has since been superseded by 22090 and 32060, so any of those three should work. Although, OLT's side-by-side comparison of 12050 and 33010 isn't very reassuring.
https://www.clublexus.com/forums/sc4...ps-please.html
There's 22090 again. Sounds like either that or sticking with my 33010 is the best bet. Crazy numbering scheme!
https://www.clublexus.com/forums/per...ps-sensor.html
Toyota shows the 89452-12050 superseded to the 89452-33010 and it is discontinued. The new numbers are 89452-22090 and 89452-32060.
https://www.clublexus.com/forums/sc4...ps-please.html
according to toyo-diy the part number is:
89452-50010 (04/1991 - 08/1992) which supercedes to 89452-50020
89452-50020 (09/1992 - 12/1993)
However the part number 89452-12050 supercedes to:
89452-22090 toyota
89452-33010 lexus but multisupercedes to 89452-22090
89452-50010 (04/1991 - 08/1992) which supercedes to 89452-50020
89452-50020 (09/1992 - 12/1993)
However the part number 89452-12050 supercedes to:
89452-22090 toyota
89452-33010 lexus but multisupercedes to 89452-22090
09-05-14, 10:17 AM
#5
The replacement TPS didn't change anything. I still couldn't find a spot in the range that met both feeler gauge criteria, and the 40 mph light throttle bucking hesitation is still there. Time to get a better multimeter and see if that's all it needs for proper calibration.
09-08-14, 07:36 AM
#7
Yep, replaced the upstream (main) O2 sensors recently and it had absolutely no effect whatsoever. My dealer service history shows them having been replaced back around 50,000 miles, so unless they had been done again since then, they had 140,000 miles on them. They were reading a bit lazy according to the multimeter, but apparently not enough to affect things. I was really hoping that was it.
When I unplug my TPS, the bucking goes away. So unless something else is causing the bucking and is dependent on the TPS signal to do so, it seems pretty definitive that the TPS is to blame. But, the new TPS does it, too, so that complicates things... I ordered a much better multimeter which should arrive in a couple days. Hopefully, that will allow me to get the darn thing within spec. I'm not convinced my cheap meter is reading properly at those really low values that come into play when setting the TPS to spec.
When I unplug my TPS, the bucking goes away. So unless something else is causing the bucking and is dependent on the TPS signal to do so, it seems pretty definitive that the TPS is to blame. But, the new TPS does it, too, so that complicates things... I ordered a much better multimeter which should arrive in a couple days. Hopefully, that will allow me to get the darn thing within spec. I'm not convinced my cheap meter is reading properly at those really low values that come into play when setting the TPS to spec.
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09-08-14, 07:41 AM
#8
I set my TPS to spec on my 92 and it was worse afterwards, so what I did was while the engine was idling, I messed with the TPS, turning it this way and that, very slowly though, once I found the lowest idle setting, I tightened the TPS and the engine idles perfectly. I'm not gonna lie though, there is still a tiny fraction of bucking that occurs at 40 at mid-throttle. Thats with the exhaust re-done, rebuilt ECU, new TPS and o2 sensors...
09-08-14, 08:01 AM
#9
Sadly, I've tried the hand adjustment method numerous times and still ended up at the same point. My bucking is quite bad. I drove a road last week that was a 40 mph stretch with rolling hills and tight turns. It would have been a spectacular drive except that I spent the entire time in that partial throttle range because of the nature of the road, and it was absolutely miserable. If I stay out of that bit right around 40 mph and 1400 RPM, the car is as smooth as can be.
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