Throttle Position Sensor Adjustment Options

[Island_Racer]

Hello,

I had to pull off my tps recently and i installed it again without much thought......i got misfires at WOT and it hit me instanly the tps needs to be adjusted properly......

What is the procedure for said task? And what resistances shud i be reading between which terminals....

[match220]

Hello,

I had to pull off my tps recently and i installed it again without much thought......i got misfires at WOT and it hit me instanly the tps needs to be adjusted properly......

What is the procedure for said task? And what resistances shud i be reading between which terminals....

testing:
the TPS is adjustable and you will need a mic to get it adjusted back to where it was (unless your TPS still has the paint dot on it from where they marked it when it was set) Use the below diagram as a guide to set it back to normal. Or you can look up more info here that might help.


Testing the TPS itself:
If your car is 95 or older you can test the idle switch in the TPS by connecting TE1 and E1 in your diagnostic service port under the hood. If it is 96 or older you can plug in a scan tool with the function test (or a $20 ebay bluetooth OBD reader and the free Torque app in the Android market) and check the TPS sweep by slowly moving the gas pedal and watching the graph (or number value) raise with the pedal movement.

extra info:
Toyota TPS sensors are all wired the same, if they are a 4 pin connector. On one end of the 4 pins is a brown wire (ground[e2]), the opposite end of the brown ground wire is the TPS supply (5v[vcc]) the wire next to this is the TPS signal[VTA], and the one beside the brown wire is the idle switch[IDL]. (sorry, I don't remember the pin order, just where they are in reference to the brown wire). In order they are: E2, IDL, VTA, Vcc.

Warning:
The ecu uses the 0 - 5 volt signal generated between pins 2 and 3 as it opens and closes. DON'T measure the voltage level with the TPS harness connected, or the signals coming off of the ecu. Multimeters can potentially kill an ecu.

[Island_Racer]

Ok, so i position the tps based on the specs: engine is hunting at idle
I decided to check the base timing anyway: it was waaaaay gone not even in the area that has increments (car wont even drop its idle when the pins are shorted...it was still hunting between 1000-1300....but CEL was flashing so i imagine it was in the calibration mode)
I rotate the distributor to full retard: timing comes back as far as 16 btdc
So i loosen the tps (after marking the spot) and put it to full retard as well: timing goes to 5btdc and the car idles at 700-800 (the correct idle for base timing mode, i also cud move the distributor to the 10 if i wanted)

Instead

I turn the tps slowly to see if i cud catch the 10 using it (distributor is at full retard still): any movement at all away from the tps at full retard makes the timing advance back to 15-16

So i put the tps back to that full retard position and set the dizzy to get the right timing....got it to 10 btdc (pull out the shorting wire)

I go for a drive and get a few good pulls right up to redline but then after awhile, at WOT (running 10psi) i get misfires at 5000 and up rpm
It'll miss...continue pulling...miss some more...then continue pulling up to redline (i was so scared while doing it, but wanted to see if it wud clear up as i went higher)

But it isnt every time i go WOT this happens...sometimes it pulls perfectly up to red line and sometimes it does the other

I broke my laptop so i cant log info rite now to analyze, but from what i see right when it happens

AFR's in the 10's
Fuel pressure is ~54
Boost seems to hold steady (10psi)

If i raise the boost pressure to 12psi: Misfires happen right as it hits full boost @ WOT even before 5000

I put in new BKR6E plugs with 0.031" gap. Checked distributor and wires....

I used to run 16 psi and had BKR7E plugs with 0.028" gap perfectly fine.....sigh

Its the fact it doesnt always happen that is making it hard for me...

This post has been edited by Island_Racer: Dec 13, 2013 - 10:20 AM

[match220]

I'll read over this more tomorrow after I get some sleep (since I haven't slept yet), but if your car is pre 96, you have to jumper two pins in the diagnostic port under the hood to check the timing. TE1 and E1? You have to verify that in your book though to be sure I am right. Or it might say on a sticker under the hood.

[Island_Racer]

I'll read over this more tomorrow after I get some sleep (since I haven't slept yet), but if your car is pre 96, you have to jumper two pins in the diagnostic port under the hood to check the timing. TE1 and E1? You have to verify that in your book though to be sure I am right. Or it might say on a sticker under the hood.

Lol u shud get the sleep man....i did short the wires in my description above, TE1 and E1 and got the constant flashing CEL....

This post has been edited by Island_Racer: Dec 13, 2013 - 10:19 AM

[match220]

If you are getting a constant flashing CEL when you jump the pins then you should check the code and see what it breaks out to. Long blinks are the first digit, short blinks are the second digit, so 1 long and 4 short is code 14.

Concerning the TPS, adjust it with a mic based on my first response.

Concerning the air/fuel ratio under load, it is good to have your AFR drop when you are under load. AFR set to lambda with high boost produces too much heat and can damage the turbo. When tuning, I would gradually lower the AFR as the boost level increases. Since you are only hitting 10 psi, you could safely set it to 11.5 AFR and still get a lot of life out of the turbo. Anything more than 10 boost and I would change it back to 10 AFR. When you get another laptop to interface with your engine management look for a table called "AFR setpoint" or something like that.

Does your engine management automatically adjust the fuel going into the engine to reach the set AFR or do you have to configure that? You should have a fuel map that you can adjust, just lower the numbers in the cells of the map on the RPM/load that you want a higher AFR. Keep doing runs until you hit 11.5 AFR where you want it. Also if you have closed-loop control enabled, I would disable it while you are tuning. (all of course after you get a laptop)

As far as the miss above 5k, I don't know what to tell you unless it is a failing injector.

This post has been edited by match220: Dec 13, 2013 - 6:06 PM

[Island_Racer]

ok, moved on from the TPS to the MAP sensor.

Firstly, Is it correct to say the map sensor is what feeds the boost gauge (inside the stock cluster) info so that the needle goes up.

if so, I think the MAP Sensor is faulty;

* at 10 PSI the boost gauge needle goes above the last increment (almost looks like it wants to pop off....lol)

* anything above 10 PSI and at WOT once full boost hits the car misfires no matter the rpm (rich misfire...at 12psi boost - 54 psi fuel pressure)

* you can smell fuel

* gas mileage is horrible

...so i started testing the sensor. It is getting 4.97V fed to it. i only have a vacuum hand pump currently so i checked the vacuum side for errors in spec....all fell into good spec.

only to test it under +pressure now.

so while i wait to obtain a hand pump to test that....anyone have other advice on stuff to check....

This post has been edited by Island_Racer: Dec 28, 2013 - 4:21 PM