Notices
86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

Help with TPS test

Thread Tools
 
Search this Thread
 
Old Aug 3, 2015 | 02:55 PM
  #1  
Sidherish's Avatar
Thread Starter
Registered User
 
Joined: Aug 2015
Posts: 5
Likes: 0
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
Reply
Old Aug 3, 2015 | 03:52 PM
  #2  
scope103's Avatar
Registered User
15 Year Member
 
Joined: Sep 2007
Posts: 8,379
Likes: 871
From: San Francisco East Bay
Originally Posted by Sidherish
...
i consider myself a pretty capable mechanic but an electrician i am not, ...

like i said i can follow directions but i just dont know how to read the dang multimeter.
Then you've come to the right place. In case you haven't noticed, this is the 21st Century, so to be a "capable" mechanic you have to know a LOT about electricity. Especially how to use a mutimeter. http://autoshop101.com/forms/h4.pdf At least you have one ... that puts you ahead of a lot of guys out there.

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.
Reply
Old Aug 3, 2015 | 04:06 PM
  #3  
Sidherish's Avatar
Thread Starter
Registered User
 
Joined: Aug 2015
Posts: 5
Likes: 0
Originally Posted by scope103
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.
VCC-E2 tests at 3.8k, so that indicates that the tps is flawed?

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; Aug 3, 2015 at 04:24 PM.
Reply
Old Aug 3, 2015 | 05:27 PM
  #4  
Sidherish's Avatar
Thread Starter
Registered User
 
Joined: Aug 2015
Posts: 5
Likes: 0
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?
Reply
Old Aug 3, 2015 | 07:10 PM
  #5  
RJR's Avatar
RJR
Registered User
 
Joined: Jul 2012
Posts: 1,776
Likes: 110
From: Northern Colorado
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.

Last edited by RJR; Aug 3, 2015 at 07:16 PM.
Reply
Old Aug 3, 2015 | 07:17 PM
  #6  
Sidherish's Avatar
Thread Starter
Registered User
 
Joined: Aug 2015
Posts: 5
Likes: 0
Awesome, I'll replace and update
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
moparbay
86-95 Trucks & 4Runners
40
Mar 10, 2023 03:50 PM
larrys93pickup
86-95 Trucks & 4Runners
6
Sep 17, 2015 07:05 PM
sanctfy
86-95 Trucks & 4Runners
10
Sep 13, 2015 06:33 PM
Boomer8404
86-95 Trucks & 4Runners
3
Sep 10, 2015 09:01 AM
moparbay
86-95 Trucks & 4Runners
1
Sep 3, 2015 12:48 PM




All times are GMT -8. The time now is 05:40 AM.