Throttle Position Sensor values?

[MIKe30]

Searched, no luck. Closest thing I found was a FredK post saying 1600 ohms if i'm not mistaken, didnt mention open/closed or which contacts.


Piss poor haynes manual doesn't mention it. Anybody know what the values should be when the throttle is closed, then fully open? Right now I'm getting...1.4Kohms butterfly closed and 4.9Kohms open on one set of contacts, then 5kohm butterfly closed and 1.5kohms open on the other set.

This right or way off? I'll compare it to another 2 tps's i have in the garage tomorrow.

I'm getting a maf code and a evap system running losses, but i'm trying to rule out tps as a cause of the erractic take off's (read: jerky) and stalling. Also, right around 2-2.5k rpms with engine in neutral, car does not continue to accelerate more with steady throttle input, but bounces revs like a VERY lopey idle then after some more steady throttle input shoots up to 3.5k and can rev as much as I want. Also part of the reason for checking this tps.

Thanks.

[z31maniac]

Did you fix your vacuum problems yet?

[flyboyx]

when you checked your resistance across the throttle position sensor, you are basically saying that the values between the poles are the inverse of each other between open and closed. i am not sure about the actual resistance value, but that sounds right. seems like i remember one of the members (perhaps mongol) posting something like this on his m54 thread. also, if you change the scale on your volt/ohm meter, you can make it read 1500 and 1400 ohms respectively which is pretty close to what you mentioned fredk posted.

[hoveringuy]

The resistance is one way to measure it. I've been reading the voltage at the center pin with ignition "on". It should be between around .4 to .5 volts and go up to around 4.5v at full throttle.

I also log that signal on my LM-2.

[MIKe30]

Did you fix your vacuum problems yet?

No, not yet. Do you think lack of pcv or air/oil seperator could be it? Haven't really looked into it much honestly. This tranny (hopefully **knock on wood**) issue has consumed me. Going out tonight to work on that.

when you checked your resistance across the throttle position sensor, you are basically saying that the values between the poles are the inverse of each other between open and closed. i am not sure about the actual resistance value, but that sounds right. seems like i remember one of the members (perhaps mongol) posting something like this on his m54 thread. also, if you change the scale on your volt/ohm meter, you can make it read 1500 and 1400 ohms respectively which is pretty close to what you mentioned fredk posted.

I realize 1.4k ohms = 1400 ohms (I deal with resistors and low voltage electricity every day :razz:), and that what I mentioned was close to what I remember reading in a post by fredk, but he did not mention what the low value should have been and what the acceptable tolerances were.

The resistance is one way to measure it. I've been reading the voltage at the center pin with ignition "on". It should be between around .4 to .5 volts and go up to around 4.5v at full throttle.

I also log that signal on my LM-2.

My e30 manual has a method to measure and properly adjust the tps when replacing. I had to do it on my old m20. I don't understand why this garbage haynes doesnt show it for the m50.

Still looking for range and acceptable tolerances if anybody has it on paper. I tried finding the e36 bentley pdf but the links are down over on bf.c. For some reason it's no longer on my computer.

[z31maniac]

I don't know for sure that it can cause that, but I do know trying to track down a problem with the engine is tough when you have other unresolved issues.

Get the vacuum lines/system sealed and good to go and then see if you continue to have the rough running.

[jrdeamicis]

No, not yet. Do you think lack of pcv or air/oil seperator could be it? Haven't really looked into it much honestly. This tranny (hopefully **knock on wood**) issue has consumed me. Going out tonight to work on that.


I realize 1.4k ohms = 1400 ohms (I deal with resistors and low voltage electricity every day :razz:), and that what I mentioned was close to what I remember reading in a post by fredk, but he did not mention what the low value should have been and what the acceptable tolerances were.

My e30 manual has a method to measure and properly adjust the tps when replacing. I had to do it on my old m20. I don't understand why this garbage haynes doesnt show it for the m50.

Still looking for range and acceptable tolerances if anybody has it on paper. I tried finding the e36 bentley pdf but the links are down over on bf.c. For some reason it's no longer on my computer.

My TPS just died today but did not throw a code and I had to diagnose it.

The accepatble range is 800Ish ohms --> 3800-4500 Ohms.

Mine read 600 to 1500 @ WOT.

Let me go get the EXACT measurement out of the book.

[MIKe30]

My TPS just died today but did not throw a code and I had to diagnose it.

The accepatble range is 800Ish ohms --> 3800-4500 Ohms.

Mine read 600 to 1500 @ WOT.

Let me go get the EXACT measurement out of the book.

Thank you. Please do. Tired of this car, contemplating parting the pile.

Can you PRETTY PLEASE post how to test the MAF? I'm getting 12v between the black and red/white. getting 2.5ish-4ish volts (2.5ish idle, climbed to almost 4 when giving some throttle) between the brown/orange and yellow. 10k ohms between the brown/orange and yellow with key off and plug unplugged. Of course open between the power red/white and black.

Any thoughts? NOTHING changes with the plug on or off the hfm and it throws a maf code. hfm must not be working at all. Just another line on the list of problems...

[jrdeamicis]

Thank you. Please do. Tired of this car, contemplating parting the pile.

Can you PRETTY PLEASE post how to test the MAF? I'm getting 12v between the black and red/white. getting 2.5ish-4ish volts (2.5ish idle, climbed to almost 4 when giving some throttle) between the brown/orange and yellow. 10k ohms between the brown/orange and yellow with key off and plug unplugged. Of course open between the power red/white and black.

Any thoughts? NOTHING changes with the plug on or off the hfm and it throws a maf code. hfm must not be working at all. Just another line on the list of problems...

Ok hommie. Check it. No matter how frustrating now it is you have to remember. You are changing LOTS of stuff. Be patient with it and you will come out victorious. It took me 8 months to build mine. But I started building the car from a chassis bare. I took my ETA stripped it down and built it the way I wanted... I know it gets tough when shit starts breaking. But stay patient and you will learn alot.

Lets go backwards.

Yes. Your HFM is dead if nothing changes.

Btw. If you part your car, you will thourougly regret that.

[jrdeamicis]

The MAF doesnt see right but the TPS is.

[jrdeamicis]

Oh btw. My car threw a MAF code for a dead TPS (since it thought the MAF was reading wrong for the TPS)

[MIKe30]

Oh btw. My car threw a MAF code for a dead TPS (since it thought the MAF was reading wrong for the TPS)

Thank you very much for posting that.

Unfortunately, what you cited seems to be the maf info for an obd1 plug, mine is a 4-pin obd2 plug. Don't know how much it differs

Need to find my fluke, this radio shack special isn't very smooth and the readings lag too much for my liking. Flukes have a way of dissappearing...

[jrdeamicis]

For sure. I have owned a couple flukes and they always disapear.

Ok. I have been thinking about your problem. Please refer to new thread I am making.