New tps issues

[Kgardner350]

So my new truck has been having a problem particularly when cold. When shifting from 1st to 2nd it would shift up and down quickly a couple times and then continue through the gears normally. I had a tps code at one point and talked to a local transmission shop and they mentioned it could be the throttle position sensor. I hooked up the shops scan tool and noticed the old sensor would only read to 87% not 100% when throttle was all the way down. I bought a new tps and replaced it along with the apps learn. It worked at first kind of but only got to 91%.

I took it for a drive. It did not solve my hunting issue so I looked down at the scanner and now the tps was reading 0% only. This is confusing as I would think if the tps was reading 0% the truck would not drive but it did as normal. Any wisdom here would be appreciated.

[Threadzy]

Does the WTS light come on as soon as you turn the key on? Have you tested for AC noise?  Have you done the W-T ground reference mod? 

[IBMobile]

A bad TPS can cause a delayed or no 3-4 up shift, no 4-3 down shift, or a 3-4 upshift immediately after the 2-3 up shift.   The 1-2 shift problem can be valve body/kick down cable or governor circuit electrical fault.   Check the trans fluid level and condition along with the kick down cable adjustment and swap the transmission relay with the horn relay in the PDC to start with.

 

If you're going to replace your TPS use a "Timbos" apps.  They are better than the factory part and not made in China like the ones you see being sold for $25-$50.  Those cheap ones can give you a head ache.   Try adjusting the TPS/APPS the way the article below shows it.  You may want to try it with your old TPS also.

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/stock-apps-sensor-voltage-adjustment-r34/ 

 

 

 

[Kgardner350]

Yea my wait to start light shows, and the ground mod had already been done.

 

As far as the TV cable goes, I was reading about that and have made adjustments both ways and it didn't seem to affect it much. Have you seen any procedures on proper adjustment for the TV cable other than just messing with it until it's right? From what I understand sometimes the line pressure has to be adjusted with the TV cable ?

[Threadzy]

I was told you adjust it so your 1-2 gear change at WOT is between 2,800-2,900 rpms. That’s how I adjusted mine and it works fine. 

[IBMobile]

I did the same as @Threadzywith no problems.

This may help you understand how the transmission shifts.

 

From @Dynamic 11/6/2015

You basically have two different pressures at work in the VB when determining upshift and downshift points.

First, there is governor pressure, which is determined by road speed. Early transmissions (46RH, 47RH) used a mechanical governor on the output shaft, and the newer RE transmissions replaced the mechanical governor with the governor pressure solenoid/transducer setup that we all know and love. The PCM generates the governor pressure electrically via the solenoid, and monitors the governor pressure via the transducer. Either way, the faster you are driving, the more governor pressure...

Second, you have throttle valve, or TV pressure. This pressure is determined by throttle position. When you press on the throttle, the TV cable pulls on the lever at the transmission, which rotates the TV lever shaft, which then presses on the end of the TV plunger in the VB. The plunger then loads the TV pressure regulator spring more heavily which, in turn, increases TV pressure; the more throttle, the more TV pressure...

There are two shift valves in the VB that use governor and TV pressure to determine shift points; the 1-2, and the 2-3 shift valves. (The 3-4 shift valve and TCC lockup valve are controlled separately by the PCM via solenoids and do not use governor or TV pressure to determine their shift points.) At each shift valve, governor pressure acts on one end of the valve, constantly trying to stroke the valve to the "upshifted" position. At the other end, there is a spring holding the valve in the "downshifted" position. In addition to the spring, TV pressure also acts on that same end of the valve, assisting the spring in holding the valve in the "downshifted" position.

When you are at a standstill, governor pressure is at a minimum (basically zero psi) and the shift springs hold their valves in the "downshifted" position - first gear. As you take off from a stop, governor pressure begins to rise, acting on the end of the shift valves. If you are light on the throttle, TV pressure is very low and governor pressure quickly rises to the point that the force of the 1-2 shift spring at the other end of the valve is overcome and the 1-2 shift valve strokes, commanding a 1-2 upshift. The transmission is now in 2nd gear...

If you are heavier into the throttle, TV pressure assists the spring with greater force, making it necessary for governor pressure to build to a higher level before the force of the spring AND the hydraulic force of the TV pressure acting on the end of the valve to be overcome. This is how the transmission holds each gear for longer when you are heavier into the throttle.

As you continue to accelerate, governor pressure continues to rise until the 2-3 spring force (and whatever level of TV pressure that is acting on the 2-3 shift valve) is overcome and the 2-3 shift valve strokes, commanding a 2-3 upshift - 3rd gear...

When commanding a downshift, you press on the throttle harder and TV pressure rises. When TV pressure rises to the point that (with the spring's help) governor pressure can be overcome, the valve will stroke back to the "downshifted" position and either a 3-2 or 2-1 downshift is commanded, depending upon which gear you were in. If the throttle application is abrupt enough, and TV pressure rises quickly enough, both valves will be stroked to the "downshifted" position nearly simultaneously, and a 3-1 downshift will occur.

This is kind of a simplified explanation of what goes on in the Dodge valve body for 1st - 3rd gear. As I stated earlier, 4th gear (OverDrive) and TCC are controlled directly by the PCM via their respective solenoids.

[Kgardner350]

I replaced what I thought was a faulty new tps and I have similar issues it does not read 100% throttle.

 i hooked up my scan tool today after driving the truck and noticed that the pcm is reading 0% tps at idle but the ecm is reading 9.8%. Also I now have a code that I thought I had fixed with a new crank position sensor- p1690 injection pump doesn't agree with ckp. The wierd part is it doesn't show the code unless the truck was running. I'm having concerns that the ecm could be faulty ? I ordered a autel mk808 data tool that will hopefully be in soon so that I'm more sure that the data showing on my cheaper tool is correct. 

This has really got me scratching my head.

[Mopar1973Man]

Timbo APPS is the best solution for apps sensor. 

[Kgardner350]

Yea I went to order a timbo sadly they are on back order. Went with a ntk for the time being