Thursday, October 03, 2013 - 09:09 pm, by: John Stafford(Johng12)
I am trying to find out if there is a problem with my throttle position sensor. I have followed the procedure shown in the Soarer Bible but have not come up with their numbers for resistance.
The page is 298. There are 4 blades on the plug named as follows: VC VTA IDL E2
E2 is the earth and so it gets connected to one of the wires of my multimeter and then the others are tested with the other wire as follows:
Test #1. VTA is tested with zero stop clearance on throttle and should read .34 to 6.3 ohms. My test results: 700 ohms (.7 k ohms) on both my 31 and my 32. Way above spec.
Test #2. VTA is then tested at wide open throttle and should read 2.4 to 11.2 k ohms (2400 ohms to 11200 ohms) Note: It should go up to this wide open throttle figure, evenly, as the throttle is opened fully from stop. My test results: 3200 ohms (3.2 k ohms) and 3.4 k ohms for the 32. Right on spec. for both cars. It rises from 700 ohms on the throttle stop to 3200 ohms on full open throttle, evenly and without fluctuations.
Test #3. IDL is tested with 16 thou clearance at the throttle stop and should read .5 k ohms or less (less than 500 ohms). My test results: 1300 ohms (1.3 k ohms) on both cars. On the very low side of spec. Too low?
Test #4. IDL is then tested with 26 thou clearance at the throttle stop and should go off the scale (infinity). My test results: 1.3 ohms on both cars. It then rises sharply to infinity, off the scale when I have about 60 thou clearance from the throttle stop. Nothing like spec until the throttle is opening properly and then no worries.
Test #5. VC is tested with throttle wide open and should read from 3.1 to 7.2 k ohms (3100 ohms to 7200 ohms). My test results: 3.94 k ohms (3940 ohms) on full throttle on the 31 and 4.4 ohms (4400 ohms) on the 32. Right on spec.
This is my wording of the scale diagram given in the Soarer Bible (Eng2 page 298 on). Please correct me if I have misunderstood any part of the test procedure.
When you compare my test results to spec. does anyone have comments or advice and should I be changing my sensors. They are not cheap! What should the effect of these out of spec. readings be for me?
Thanks for taking the time to read and comment. Cheers
John Stafford DieHard Qld. Soarer UZZ31 GT-L V8 and a UZZ32 # 514
Monday, October 07, 2013 - 07:35 am, by: John Stafford(Johng12)
Does anyone have experience with changing out a Throttle position sensor (TPS) and if so why did you change it (replace it) and what was the fruit of that replacement?
Tuesday, October 08, 2013 - 04:17 pm, by: Evan Kaio(Knave)
Have mucked about with the tps a while back. I didn't change mine as only the screws on the side became loose.
John Stafford wrote on Thursday, October 03, 2013 - 09:09 pm:
Test #1. VTA is tested with zero stop clearance on throttle and should read .34 to 6.3 ohms. My test results: 700 ohms (.7 k ohms) on both my 31 and my 32. Way above spec.
I am sure the resistances 0.34-6.3 Ohms quoted in the bible is wrong, I think it should be 0.34- 6.3 K Ohms. My test was 5.9 K ohms.
Tuesday, October 08, 2013 - 05:47 pm, by: John Stafford(Johng12)
I have had a miss when under full throttle, leaning right out. I put a Air fuel meter gauge on it and it went to default of 22.4 when I floored at about 2500 revs, both on petrol and on LPG. I put new plugs in to fix this last time it happened but it has never been this bad before.
I just bought 2 new TPS sensors for both my cars as they are reading the same number, but the 32 doesn't have a miss. I will measure the new ones, as no one has responded except you Evan, to my plea .
I will be the expert when I solve this.
My cruise control has never been very good in both cars, not always coming on when I want it first go and I read that this is sometimes due to a bad TPs too, and as I am testing the Aquatune system I need every sensor working properly to know how good it is.
It is definitely giving me a power boost, both with petrol and with LPG, more with LPG, and has nearly fixed the problem with the miss in the 31 by giving it a boost with the Hydrogen and water. There is still a lag though.
I am not getting any better economy with the Aquatune yet but we are going to run it to each of the inlet runners and will see what that does, instead of just going in to the plenum after the throttle body. I am sure I have more power than you could get with extractors and exhaust but haven't done any dyno testing to prove anything.
I am always surprised how much fuel my 31 uses around town on a cold motor and am hoping to get better economy with the replacement of the TPS. We will see. And then more again with the new installation of the Aquatune hydrogen system.
The sensors should be here early next week I hope, so we will see what happens with them. I have just put new O2 sensors in both cars and new thermostats and new Coolant temp sensors. Cheers John
Saturday, October 19, 2013 - 09:51 pm, by: John Stafford(Johng12)
Ok, I have replaced the TPS and think you are right Evan, all of my 4 TPS sensors tell me that it should read K ohms, not ohms. Toyota probably sent out a memo to adjust this typo but never made it to the Soarer Bible that we have I suppose.
The TPS did not solve my miss problem so at the end of the line I went and bought a new set of NGK copper spec plugs to completely eliminate the possibility of it being as simple as a plugs issue after all my work, and they made no difference. Still have this big miss when I apply full throttle.
I will start a new thread, hoping that someone will see it and come on board with some insight as to where to go from here? Cheers John
Tuesday, October 07, 2014 - 08:05 pm, by: Rob Charles(Pearl_white)
Bumping old post!
John, did you ever get to the bottom of it? I would like to suggest ECU failure if you have not already found the issue out. Caps burst (as we all know) and cause a range of nonsense issues.
I refer you to these links: Note how tps and ecu talk to eachother.
Tuesday, October 07, 2014 - 09:17 pm, by: John Stafford(Johng12)
Hi Rob, I have other threads about my long term problem with miss on my 31. In the end I found that it was nothing but the fuel ECU connection. I used contact cleaner and pushed the connection on and off many times to ensure that it was clean and no problems since.
I had restricted my LPG jets too, upon the advise of my LPG installer but have just recently removed the restrictors and have found more power and better response without compromising economy.
As for the TPS settings: I found that if I turned off the air con I could tune it by ear without feeler gauges. If you aim for the lowest revs with evenness it should be fine. I have a good TPS for sale if you know anyone who needs one ($40).
Wednesday, October 08, 2014 - 10:05 am, by: Rob Charles(Pearl_white)
Great to hear John!
It seems that lots of Soarer issues these days are 'dodgy connections' as well as electrical issues. Minor issues which cause major grief. I've tried 3 tps's in total - each act the same. I note the wires have split out of the black plastic sleeve just under where tps screws on above the left cylinder head near intake. Seems like the black sleeve is leaning on cylinder head and heating up - which caused it to split in the past.
I read that someone had tps issues when car was warm and they also had a split in the sleeve. Car got warm, heated wires up, caused many issues. The guy electrical taped the wires and had no more issues... Maybe i'll try that...
When I set the tps all the way counterclockwise so the revs are at the lowest, I get a miss at 2000rpm, and stutter and jerk when the foots off the throttle... By moving tps towards center, the misfire is gone - but i have a lack of power... A hyundai excel will beat you at the lights til about 50kmh probably... Also, my car has an idle looping issue in park. When its happening, and tps is turned to the lowest rpms, the car loops over n over n over. When tps is set to the middle or highest revs, the car won't loop - and instead wants to rev til 3000rpm or so in park...
So, soon as i get a feeler I'll check it again - but in the meantime, the lack of power is better than stuttering and jerking every time accelerator is touched.
- gotta check the iacv/ ecu out also. Sigh...
Also, John - does your TPS come with the wires, or is it just the device itself?
Thanks
John Stafford DieHard Qld. Soarer UZZ31 GT-L V8 and a Ford Territory Ghia AWD
Wednesday, October 08, 2014 - 09:26 pm, by: Tim Schroeter(790)
Hi Rob. Thanks for the ECU links! I was about to reco 2 ECUs, not knowing the electros' had to be low ESR types. Your post has saved me wasted hours. My old science teacher used to say. 'An expert is not someone who knows the answers, but knows where to find them.' Thanks again for the heads up. Tim
Previous
. 
