I searched and found some threads with similar sypmtoms/questions, but couldn't pinpoint a definite answer.

First I installed an apexi S-AFC II, by going to the check sensor menu at idle it said my throttle was giving 2 volts or so. Didn't surprise me since the car was idling pretty high.

Went to adjust tps using resistance method, sure enough it was out of spec, after turning the screw a good amount it was close to 1k Ohms. Good

Turn car on, idle MUCH better, right about 750 approx. I'm very happy at this point.

Then I realize, by checking with the SAFC that it measures WOT @ maybe 30%, Now I am worried.

Check With the DMM and sure enough, 4.7 Ohms @ partial throttle...

Is this normal, I read some things about secondary plates and stuff but no real confirmation..

Also if I give it a PUNCH of the throttle MM goes kinda crazy, Not sure if its due to the resistance changing so fast or the tps being busted, but if i give it light throttle it follows the path without any jumps or anything..

My idle now fluctuates between 600-800 like another user mentioned and while in that range my engine shakes, but when I give it light gas up to about 800 or so or a LITTLE more it smoothes out to where I rememered it being. Any ideas?

I know this is a long post, I tried searching but most I could find was how to adjust the tps and then people mentioning my symptoms here and there.

Thanks in advance for the help.

Dan

 

I thought the S4's only had a narrow range TPS?

The S5 TB has 2 TPS sensors:
A narrow range for deceleration fuel cut & idle.
A wide range for MOP.

I presume the SAFC dosen't care about WOT.
It should get what it needs from the AFM & tach.

 

I am not sure about the range of the tps, my main concern isn't what the S-AFC needs, its more that the TPS is functional... The S-AFC merely pointed me in the right direction and has been helping me see how the car is running without having to hook up the multimeter everytime I want to see.

The logic behind me doing this is upon me seeing that the S-AFC was giving me this kind of reading I went and actually hooked up the Multimeter to find out for myself and the readings were very similar...I don't know if my logic is correct in assuming that I can use the S-AFC to help me keep track of it but since it (at least in my mind) is giving me an acurate voltage reading of what the ecu is seeing, that I can moniter how the TPS is actually sending an input to the ecu...

I may be completely wrong for some reason...which is why I came to you guys for assistance

SureShot: I will definitely investigate into the range of the tps, but I do see where you are coming from with the S-AFC really only caring about the AFM and the Tac....I see your logic there, and thanks for the input.

Any ideas?

Dan

 

My quickie on-the-fly TPS check:
Next time you're on a flat open road with no traffic. Cruise along at about 3K rpm in 3rd or 4th. Lift off the throttle. This should give a fuel cut on both rotors as you back down. The motor is just pumping air. Very gently pick up just the slightest throttle. With practice you can hear the rough sound of only #1 rotor getting fuel, while #2 pumps air. Then adding just a little more throttle, #2 comes on.
You can also do this as you slow down in gear and the throttle is very near, but not quite at idle.
As you lift the throttle you can hear the #2 fuel cut before #1.
When you get down to near 1500rpm fuel comes back on to prevent stalling.

 

Are you testing/adjusting the TPS with the car at full operating temperature? I can not emphasize enough how important this is. I could test mine when the engine was cold and it was in spec and swept smoothly as pretty as you please. However, when I tested it at operating temperature I discovered that my narrow range sensor read 4.7 Kohms and would NOT adjust at all nor did it change at all.

My .02 so far.

Darren

 

Oops - I forgot not every one has removed the fast idle warm up cam.

 

I am testing it at operating temperature... Today I just started her up and was impressed that it immediately started idling at around 750, so I took my girl out for a quick spin around the neighborhood when I got back, the car was at operating temp and idling at 1500 or so....confusing.

I definitely did adjust it @ operating temp the last time, I dunno but I think the tps is bad....

It bothers me that it reads 4.7 ohms at partial throttle and not at wide open throttle. It just doesn't seem right to me.

I am at a loss, I am hoping the electrical gurus can shed some more light on this issue for me.

I may have enough pennies now to get the car back on the road, once it stops flooding everytime I turn it off D'OH!!

Dan

 

bump

 

4.7 ohms?
The TPS resistance should sweep from 1000 ohms at idle to ~5000 ohms when the plunger is all the way out.

 

Hmmm I think the discrepency might be in the way the meter is giving me the information I am NOT sure but maybe it was saying 1K Ohm, I'll double check, if thats the case then 4.7 K Ohms at partial throttle, which is what bothers me, shouldn't it be 5000 or 5.0k at WOT not before??

Also I don't like my now lumpy 600-800 idle, I'm just not sure whats totally going on....

Thanks

Dan

 

4-6k ohms at 30% or more throttle on a s4.

 

Darn if I know what year car you have or what series.....but the clue is in the above post. If it's a series four, the tps plunger is fully released long before wide open throttle. Take a look. See? The plunger is fully released just about the same time the secondary throttle plates start to open.

Your meter is reading 4.7k ohms. And K is what? Yes. You should not worry a bunch about it not reading 5K ohms. What you should really be worried about, is if when you sweep the tps from fully closed to fully open, seeing an *OPEN* during the sweep, or something irregular in the reading. I doubt the tps is bad.

I have a personal *THING* about setting the tps using the ohms method. Personally I think monitoring the tps output to the ECU is more valid. Thats with a fully HOT engine. And running at idle to boot. You seem to have a safc or whatever to monitor the tps output. Good. It mus be tied into the tps output voltage. Good. So adjust the tps until the voltage read one (one) volt. Don't make a big deal out of it if tomorrow or the day after it reads 0.95 or 1.05. NOT a big deal at all.

But after setting it, later in the day the voltage reads like 2 volts or 1.5 (you name it) then there is something wrong. Could be a tps screw backing off but most likely the thermowax gone astray. Could be something else. Who knows

But remember.....don't double check the reading unless the car is HOT. If you go out there in the morning and check it when it's cold, I guarantee it will read more closely to 1.9 volts. That's normal. Nothing at all wrong.

 

Thank you for the help everybody, please excuse my ignorance in forgetting to put down which vehicle, for the record its a series 4 Turbo.

I will adjust the tps using the above method described (thanks hailers!) and see how it turns out.

I'll keep you guys posted.

Dan