Throttle position sensor

[jeeperskeepers]

I am looking for someone to tell me how to install and adjust my TPS once its been installed. Here's my story. I can start it up and it drives fine, but when I try to pass someone, I have no power. The mechanic said it was probably the TPS. He also said that its something that only a mechanic can install. I have issues with that...Can anyone help me out with this????PLEASE!!! PS this is on a 89 cherokee with an automatic transmission.

[Dale Aeppli]

Originally Posted by jeeperskeepers

I am looking for someone to tell me how to install and adjust my TPS once its been installed. Here's my story. I can start it up and it drives fine, but when I try to pass someone, I have no power. The mechanic said it was probably the TPS. He also said that its something that only a mechanic can install. I have issues with that...Can anyone help me out with this????PLEASE!!! PS this is on a 89 cherokee with an automatic transmission.

hi , if you email me your email address i'll send you information on the sensors on your jeep
dale email [email protected] i can not send them thru the forum

[capt. apathy]

you don't need a machanic to instal it, I installed one in my 89 just about 8 months ago. it's located on the front, drivers side of the throttle body, and is attached with 2 torx screws.

just remove the old one and install the new on in the same manner, but don't fully tighten the screws(just snug, so you can still rotate it a bit, but not so loose it moves easy), and plug back in the electrical conections.

then you need a diagnostic meter, some code readers will work. the 89's computer doesn't save codes like most cars, what you need is one that allows you to get 'real-time' info from the computer.(I use a "snap-on", but there are quite a few brands)

plug in the reader to the ports(passenger side of the engine compartment, outside the relay cover), and find the voltage readings for the TPS, the reader should tell you the norm for your jeep. (off the top of my head I think my 89 was .6v closed, and 4.6v open)

then you just turn on the ignition (don't start it), and turn the TPS until it gives you the proper closed reading. then snug down the bolts.

then hold the pedal to the floor, check that reading, then let off the pedal and make sure it goes back to the proper closed reading.

if any of them are bad just re-adjust it and try again until your open and WOT possitions are within tolorance.

you can borrow or rent a reader from many of the big-name parts houses (schucks, and autozone, both loan tools for just a deposit)

btw- not sure what a new one costs, but I picked mine up for $5 at u-pull-it, works fine.

[jeeperskeepers]

Originally Posted by capt. apathy

you don't need a machanic to instal it, I installed one in my 89 just about 8 months ago. it's located on the front, drivers side of the throttle body, and is attached with 2 torx screws.

just remove the old one and install the new on in the same manner, but don't fully tighten the screws(just snug, so you can still rotate it a bit, but not so loose it moves easy), and plug back in the electrical conections.

then you need a diagnostic meter, some code readers will work. the 89's computer doesn't save codes like most cars, what you need is one that allows you to get 'real-time' info from the computer.(I use a "snap-on", but there are quite a few brands)

plug in the reader to the ports(passenger side of the engine compartment, outside the relay cover), and find the voltage readings for the TPS, the reader should tell you the norm for your jeep. (off the top of my head I think my 89 was .6v closed, and 4.6v open)

then you just turn on the ignition (don't start it), and turn the TPS until it gives you the proper closed reading. then snug down the bolts.

then hold the pedal to the floor, check that reading, then let off the pedal and make sure it goes back to the proper closed reading.

if any of them are bad just re-adjust it and try again until your open and WOT possitions are within tolorance.

you can borrow or rent a reader from many of the big-name parts houses (schucks, and autozone, both loan tools for just a deposit)

btw- not sure what a new one costs, but I picked mine up for $5 at u-pull-it, works fine.

Thanks, I am on this first thing in the morning. I got one off of ebay for $10. Im in a VERY SMALL town and its hard to get anything around here. I'll keep you informed. Again, thanks

[jeeperskeepers]

One last thing, What do you mean by a dianogstic meter? Are you saying a Volt meter?

[capt. apathy]

no not a volt meter. and make sure you have a meter capable of giving you the TPS reading before you take the old one off (especially if this is your only wheels).

the meter,(or code reader, or diagnostic computer) plugs into the data ports (data ports are located in the engine compartment, passenger side, near the relay cover, are 2 electrical conection ports covered by yellow caps).

the cheap 'code-reader' types, generally just retrieve trouble-codes stored in your cars ECU(computer), you need one that is a little more involved than that, what you need is one that allows you to turn on the key and allow you to read, on the screen, what info the ECU is recieving from the various sensors (TPS in particular)

with the Snap-On version that I have access to you enter in your vehicle make and modle, along with key digits in the VIN, and it will take you through the different snesors and system, telling you what your readings are and what would be normal in various operating conditions.

if you can't find an apropriet tool to get the readings you need, you should be able to 'back-probe' the wires coming off the TPS with a good digital voltmeter.



WARNING**, I'm not a paid machanic, just a guy who needs his car to run and often can't afford to hire a pro. I haven't actually tried the following procedure, so you should be a little daring or desperate before giving it a try. (or if you are luck someone else will post here that knows for sure).



the problem is I can't find a procedure in my haynes book for the 89 year. (it's kind of a bastard year, and with the years before 87 and after 90 saving codes and the ECU's working a bit different it is possable that the procedures are not interchangable) the method should work but the trminals that need to be probed my be different.

the instruction I found for the 91-97 models, say that you can use a digital voltmeter and back-probe the negitive to the ground terminal, and the positive probe to the center terminal. you have to back-probe the conection, and not unplug it (since it has to be functioning, and you are just 'tapping-in' to the volt-reading being sent to the ECU.

if you can't find a regular diagnostic computer to use and need to try this way of doing it (if you are like me money is often short so paying someone is sometimes not an option), I'd recomend trying to back-probe the conector with the old TPS still on, and confirm that you are on the corect terminals, by varifying a reading that is somewhere near the .6-4.6v range and increases as the throttle is opened (this is assuming that the old TPS is still giving some kind of reading. if it's completely dead, then I know of no way to verify you are on the correct terminals before you start, and you'd just have to put the new one on and hope you're on the right ones)

good luck.

[jeeperskeepers]

Originally Posted by capt. apathy

no not a volt meter. and make sure you have a meter capable of giving you the TPS reading before you take the old one off (especially if this is your only wheels).

the meter,(or code reader, or diagnostic computer) plugs into the data ports (data ports are located in the engine compartment, passenger side, near the relay cover, are 2 electrical conection ports covered by yellow caps).

the cheap 'code-reader' types, generally just retrieve trouble-codes stored in your cars ECU(computer), you need one that is a little more involved than that, what you need is one that allows you to turn on the key and allow you to read, on the screen, what info the ECU is recieving from the various sensors (TPS in particular)

with the Snap-On version that I have access to you enter in your vehicle make and modle, along with key digits in the VIN, and it will take you through the different snesors and system, telling you what your readings are and what would be normal in various operating conditions.

if you can't find an apropriet tool to get the readings you need, you should be able to 'back-probe' the wires coming off the TPS with a good digital voltmeter.



WARNING**, I'm not a paid machanic, just a guy who needs his car to run and often can't afford to hire a pro. I haven't actually tried the following procedure, so you should be a little daring or desperate before giving it a try. (or if you are luck someone else will post here that knows for sure).



the problem is I can't find a procedure in my haynes book for the 89 year. (it's kind of a bastard year, and with the years before 87 and after 90 saving codes and the ECU's working a bit different it is possable that the procedures are not interchangable) the method should work but the trminals that need to be probed my be different.

the instruction I found for the 91-97 models, say that you can use a digital voltmeter and back-probe the negitive to the ground terminal, and the positive probe to the center terminal. you have to back-probe the conection, and not unplug it (since it has to be functioning, and you are just 'tapping-in' to the volt-reading being sent to the ECU.

if you can't find a regular diagnostic computer to use and need to try this way of doing it (if you are like me money is often short so paying someone is sometimes not an option), I'd recomend trying to back-probe the conector with the old TPS still on, and confirm that you are on the corect terminals, by varifying a reading that is somewhere near the .6-4.6v range and increases as the throttle is opened (this is assuming that the old TPS is still giving some kind of reading. if it's completely dead, then I know of no way to verify you are on the correct terminals before you start, and you'd just have to put the new one on and hope you're on the right ones)

good luck.

I am just that kind of person. But what you are saying is basically brain surgery to me. And yes it is my only wheels. The mechanic said it would go as high as 2.34 volts. That why it wasnt shifting properly. Looks like Im going to be running the freakin mechanic after all. I have the part, but not a great code reader. Thanks for your help, I'll give you the solution once its back up and running.

[capt. apathy]

if it is giving a signal (but stops at2.34), you should be able to find the wires to back probe, just have someone work the throttle for you while you find the correct wires.

another option is to just install it while very near the machanics and see what he'd charge you to just adjust it. if he's a reasonable guy he'd probly do it very reasonably. the actual changing of the part takes no time at all. just a torx driver and 2 electrical plugs.

[jeeperskeepers]

Originally Posted by capt. apathy

if it is giving a signal (but stops at2.34), you should be able to find the wires to back probe, just have someone work the throttle for you while you find the correct wires.

another option is to just install it while very near the machanics and see what he'd charge you to just adjust it. if he's a reasonable guy he'd probly do it very reasonably. the actual changing of the part takes no time at all. just a torx driver and 2 electrical plugs.

Here's the latest: I did put the new one on, and took it for a test spin. Seems to work great, lots of power. But I think I should still take over the mechanics and have him adjust it to its proper volts. I want to thank you for all the help. I'll keep in touch with the group. Bye for now

[ORLANDO88JEEP]

Is the setting the same for a 1988 Jeep Cherokee ?
Thanks

[capt. apathy]

yes, I'm fairly sure they are. not much (if any) difference I'm aware of between the 88's and 89's

[Kahu]

I have an 88 that was doing the same thing. I was told that it was probably the tps, so I changed that among other things, although I did not adjust it. Its still not running correctly and its just sitting in my driveway. Is adjusting the tps necessary? that might be the prob

[capt. apathy]

some people get lucky I had to adjust mine.

[Kahu]

ok... what if I got unlucky and it needed adjustment? Would it function poorly or would you not notice a difference. It seemed like I got my power back right after I installed it, but by the time I was on my back from going around the block, it started acting up again.

I had given up on it and its just sitting in my driveway now. If i cant fix it, Ill probably just part it out.

[capt. apathy]

depends how out of adjustment it is. mostly the symptoms are loss of power, and lousy gas mileage