tps questions

What kind of things can a tps effect? can it effect the tranny shifts and lock up for example?Or what other things can it effect?

Yes, it can affect both of the items that you mentioned because the TPS is a load sensor and both of the above functions depend on engine load.
The TPS (or throttle position sensor) is exactly that. It senses the position of the throttle blade and the PCM reads the output from it to determine how much fuel to add to the A/F mixture.

It can affect throttle response too. I noticed a big difference in better throttle response when I changed mine out with a new OEM one.

F%$#, i bet those mechanics never used a osciloscope, they probibly just metered the dam thing out. Im thinkin i should replace it, cause that is about the only thing i havent replaced, and i still got the same prob at 2000rpm theres some missing like the plug wires cross or the tranny isnt locking up. Both of those problems have been verified as fine and functional. THANKS GUYS, i appreciate the knowledge

My other post is about the prob im having lol, take a look see if ya think it could be this tps.

XJ CREEPER: How many miles on your jeep, and what year?

Lusty said:

F%$#, i bet those mechanics never used a osciloscope, they probibly just metered the dam thing out. Im thinkin i should replace it, cause that is about the only thing i havent replaced, and i still got the same prob at 2000rpm theres some missing like the plug wires cross or the tranny isnt locking up. Both of those problems have been verified as fine and functional. THANKS GUYS, i appreciate the knowledge

My other post is about the prob im having lol, take a look see if ya think it could be this tps.

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I doubt they used an o-scope too since the best way to check the TPS is to stick a voltmeter on it an watch it as you slowly move the throttle. Just need to check for proper voltages at closed and full open and a smooth transition.

An o-scope will just trace it on a screen in a graph so you can see all the spikes and drops through out the range. A volt meter wont show that, and thats what i wanted to see was that kind of a scan on paper. Unless they used a fancy volt meter that has a screen, but im pretty sure they didnt but oh well, they said it is good so i have to take theyre word for it. I ight just replace it anyway and have a spare, ill be pissed if it gets cured when i do replace it hahaha.

The TPS typically has a problem at around 1/3 rd throttle. It is in various TSB's and troubleshooting charts. The O2 sensor often acts up at near peak torque, which is just about 2000 RPM, usually at lower vacuum (with the throttle mostly open). It usually bucks and feels like the torque converter is locking and unlocking. The flat spot in the TPS retards the timing a bunch and the motor just kind of dies for an instant.
A seriously worn timing chain and/or distributor gear can also cause the motor to buck.
Grounds are always a good place to start, then connector cleaning. I always try to eleminate the easy and cheap, before changing sensors.
There are a few other causes, but they are rare.
I keep a small box full of junk yard sensors, to troubleshoot with. The whole box full, cost about as much as an O2 sensor. And is nice to have along, on long trips.
Remember the TPS, is actually a two in one thing, two halves, one half for the tranny (automatic) and one half for the motor (ECU).

TPS, is actually a two in one thing, two halves, one half for the tranny (automatic) and one half for the motor (ECU).

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Depending on the year 91 and up it's no longer dual.

Lusty said:

An o-scope will just trace it on a screen in a graph so you can see all the spikes and drops through out the range. A volt meter wont show that, and thats what i wanted to see was that kind of a scan on paper. Unless they used a fancy volt meter that has a screen, but im pretty sure they didnt but oh well, they said it is good so i have to take theyre word for it. I ight just replace it anyway and have a spare, ill be pissed if it gets cured when i do replace it hahaha.

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It would have to be a digital scope that can do a real slow trace. I've seen expensive digital voltmeters that can do this, but they aren't o-scopes that can show waveforms of higher freq signals (I do acoustic signal analysis for a living).

TPS, is actually a two in one thing, two halves, one half for the tranny
(automatic) and one half for the motor (ECU).

langer1 said:

Depending on the year 91 and up it's no longer dual.

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Yes it changed when they went to the HO engine and started using the ODB-I engine controller. After that, the ECU provides the signal to the TCU instead of having a dual signal TPS sensor.

lawsoncl said:

It would have to be a digital scope that can do a real slow trace. I've seen expensive digital voltmeters that can do this, but they aren't o-scopes that can show waveforms of higher freq signals (I do acoustic signal analysis for a living).

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A Automotive scope is a whole different animal, it's more of a computer than a Ocilliscope and can use charts to show wave forms or trends.

langer1 said:

A Automotive scope is a whole different animal, it's more of a computer than a Ocilliscope and can use charts to show wave forms or trends.

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Gotcha. You're talking about an engine diagnostic computer. I'm thinking o-scope as in electronics work. Last time I used a 0-scope on the vehicle was checking out the tranny speed sensor.