Help with TPS test
#1
Help with TPS test
95 toyota pickup with 22re motor
very low power on accel, hard to get up to highway speeds
i consider myself a pretty capable mechanic but an electrician i am not, so heres where I'm at-
testing the TPS resistance between the VTA and E2, my multimeter set at 20k, it reads .43 at closed throttle and scales up to 2.41 at wide open throttle. does that translate to 430ohms up to 2400ohms? and if so, thats way lower then it should be right?
like i said i can follow directions but i just dont know how to read the dang multimeter.
thanks guys
very low power on accel, hard to get up to highway speeds
i consider myself a pretty capable mechanic but an electrician i am not, so heres where I'm at-
testing the TPS resistance between the VTA and E2, my multimeter set at 20k, it reads .43 at closed throttle and scales up to 2.41 at wide open throttle. does that translate to 430ohms up to 2400ohms? and if so, thats way lower then it should be right?
like i said i can follow directions but i just dont know how to read the dang multimeter.
thanks guys
#2
Registered User
Join Date: Sep 2007
Location: San Francisco East Bay
Posts: 8,254
Likes: 0
Received 822 Likes
on
649 Posts
You are correct; on the "20k ohm" scale, 0.43 is 0.43k ohms, or 430 ohms. 2.41K ohms is the same as 2,401 ohms. ("k" means kilo, or in english, 1000s). The spec for WOT is 3.1-12.1k http://personal.utulsa.edu/~nathan-b...34throttle.pdf, so you are a "little" low. I'd suggest you measure Vcc-E2. That gets the entire arc of the rheostat; if it's substantially different than 2.4k you have a mechanical problem. If you have 2.4k you are low, but I don't think you're low enough to actually cause a problem.
#3
or maybe im just being neurotic? it just seems to have really low power, takes almost a whole onramp to get it up to about 45-50, perhaps that is normal for these trucks? i do get what sounds like an exhaust leak tick at idle that goes away when i rev it up, but as i understand thats probly just the way the valves sound when the 22re gets old.
-shrug- i cant really complain for a $300 truck
Last edited by Sidherish; 08-03-2015 at 04:24 PM.
#4
Update: forgot to reconnect the TPS sensor and drove about 2 miles with the check engine light on before I noticed it but it ran PERFECT with it disconnected. Tons more power, no hesitation.
So definitely the TPS then?
So definitely the TPS then?
#5
Registered User
Join Date: Jul 2012
Location: Northern Colorado
Posts: 1,776
Likes: 0
Received 109 Likes
on
81 Posts
Correlating the readings you are getting with the information scope shared suggests that your TPS is defective, and in particular, it is never telling the ECU that the throttle is more than about 2/3 open (2.4/3.8). If the ECU always thinks you're at part throttle, it will adjust mixture and timing accordingly, which will not give you full power.
At wide open throttle, the resistance between VTA-E2 should match the resistance between VCC-E2. If it's a lot lower, as in yours, the wiper arm is not getting to the top of the potentiometer arc, indicating your TPS is possibly mechanically defective.
Another possibility is that your throttle cable is not pulling the throttle completely open, so the TPS wiper arm doesn't move the full arc. Have someone push the accelerator to the floor (engine off) and watch the throttle. Then, while they've got the pedal floored, see if you can move the throttle further open from under the hood. If you can, figure out where the motion is getting lost between the pedal and the throttle. On mine, there was a rubber spacer bushing on the cable where it attaches to the pedal that had split, costing me about a half-inch of throttle cable travel.
At wide open throttle, the resistance between VTA-E2 should match the resistance between VCC-E2. If it's a lot lower, as in yours, the wiper arm is not getting to the top of the potentiometer arc, indicating your TPS is possibly mechanically defective.
Another possibility is that your throttle cable is not pulling the throttle completely open, so the TPS wiper arm doesn't move the full arc. Have someone push the accelerator to the floor (engine off) and watch the throttle. Then, while they've got the pedal floored, see if you can move the throttle further open from under the hood. If you can, figure out where the motion is getting lost between the pedal and the throttle. On mine, there was a rubber spacer bushing on the cable where it attaches to the pedal that had split, costing me about a half-inch of throttle cable travel.
Last edited by RJR; 08-03-2015 at 07:16 PM.
Thread
Thread Starter
Forum
Replies
Last Post