Topic: TPS check.

[Vodkaman]

its not a good check to check the TPS resistance. you have to check the voltage with the key on. back probe the connector with some straight pins with it still hooked up. its a three wire TPS, so its one 12V, one ground, and signal wire back to the PCM. signal voltage should be about 0.5-0.6 volts with throttle closed. and 4.8-4.9 volt at wide open. also check for a smooth voltage increase during a smooth throttle opening.

I agree that checking TPS resistance is not accurate test, but newer the less, the resistance between 5V supply (pin 1) and Signal (pin 3) should change while rotating throttle blade, or not?
Sorry for may be stupid question, but it is cold outside, and I am not sure that my multimeter will operate properly.

[Vodkaman]

Not sure, that the measurements are correct, but they are: Idle - 0,71V (0,26 according to manual), WOT - 3,77V (4,49), Input - 4,95V (5V). Is this normal, or should I replace TPS? Manual says that open loop mode starts at 2,6V above learned idle voltage, so I have only 0,4V range for ECU to operate in open loop mode. Is it enough?

[aw12345]

first question would be, why are you checking the tps voltage?
It has a check engine light on or it has a flat spot when you hit the gas when it's cold and the engine is still in open loop? The latter seems not uncommon on the 2.4L engine. Seems to me letting the ecm relearn will take care of it if everything else is good

[Vodkaman]

The reason is absolutely useless travel of gas pedal in floor direction at the speed of 60 at 4-th, 5-th, or 6-th gear. I do not feel Open Loop mode. Nothing changes, when accelerator is in the second half of it's travel, no valves clicking, no deeper sound of over fueled engine, just nothing. It even runs faster when gas is depressed a bit. I know how many obstacles could be a reason for that, but I need to check this particular subject and go further, if you don't mind of course.

[sharpxmen]

i would check fuel pressure
and do you have a "hot air intake" by any chance?

if it was tps you'd get a check engine light i think but if you feel that's the culprit then replace it, it's fairly cheap.

[Vodkaman]

 As you know, it is not that easy to check fuel pressure on 2,4 DOCH. But the first thing I did - was checking gas tank, pump and filter. They are OK.
Jeep runs fine in 1st to 3rd gear, but I newer met the floor in these gears. Sometimes I drive wife's Carisma (1,6L Mitsubishi), bo-yah!, it accelerates in 5th like mine in 3rd. And I always hear clicking noise when I press on gas too much. For me it means that ignition angle is under control, here I never heard detonation, never  in 5 years.

[sharpxmen]

you're comparing a 5000lbs vehicle with a 2200lbs one not to mention the Jeep's aerodynamic shape comparable to a brick standing up as well as the frontal area probably double the size, not sure why you'd even go there.

how did you check the pump? and has this gotten worse lately or is it just by comparison with the Mitsubishi?

[Vodkaman]

No, it is the same during these years.
I got used to that, but while the front seal was replaced, I drove Carisma, and just decided to check TPS.
Fuel pump is clean and quiet, filter is also clean.
So, what do you thing about first two posts?

[sharpxmen]

i'm not familiar with the 2.4L
.71v seems normal for closed
3.77v seems low, however as i understand it adjusts itself (the ECU) and i read somewhere that there's a procedure to reset it, something like put the key on, then press and hold the pedal to the floor until the buzzer makes a "ding" noise then turn the key off, i'm not sure if this applies to the Jeep 2.4L

if the tps was a problem and your assumption is correct (no open loop) you could check that with a OBD2 reader, there are some apps out there for iphone or androids too or some that can be used with a laptop if you buy the cable, so that might be something you want to look at before spending money on parts.

i think the problem is the Jeep being underpowered (or HP/lbs ratio) compared to other vehicles, although the "lifting the pedal and accellerating" is a concern and i would still like to hear if you have one of those CAIs pulling hot air from under the hood.

[Vodkaman]

No, my intake is stock. Read a lot of this useless staff. Temperature here in Russia is so different, that hot air is a random thing.
Manual says it shell be 0,26V at idle, 0,71 seems to be too much. But main concern is the range of just 3,0V instead of 4,3 according to manual.
I do not want to make a rase car out of my jeep, but I fill it by the bottom of my body, the engine works not properly.

[aw12345]

Is reference voltage to the sensor 5v or lower? Is the sensor ground good?
Both will affect sensor return voltage to the ecm.
By the way if the engine picks up power by letting up on the gas pedal a bit, that is almost always a lack of fuel. So fuelpressure under load is where I would start looking it should not drop off under load. TPS isn't a terribly important sensor, the map sensor does a lot more for fuel delivery and timing, it's the main sensor for determining engine load.

[sharpxmen]

good point with the ground - the sensor ground is different than the vehicle ground, which one did you use to measure the output?

[aw12345]

Also check that you actually get full throttle with the gas pedal to the floor.
Bunch of floor mats or what not can keep you from getting fullthrottle.

[Mozman68]

Make sure you get through the TPS report once you're done checking it all out....

[sharpxmen]

Make sure you get through the TPS report once you're done checking it all out....