So today I get a dead pedal / stumble off idle, erratically. First time it happened once on my 12min drive to work. Coming home it dead pedaled maybe three times. Could be dangerous when pulling out into traffic.

 

Yesterday I did a 10 hour round trip at a high rate of speed, hit 130mph per GPS on my phone, did much of the trip at 85-100mph often pulling upto 110-120. Lets just say it was some real long, real open old highway and I had a long way to go. *I was trying to get back before it got really dark, any tips on additonal lights I could mount on my bumper that are cheap and effective I am open to.

 

So the kicker is its a P0121 code, which after reading on here Moparman says is the APPS. Well I just put in a new Wells (duralast) Apps sensor maybe 18 months ago and I havnt had a problem up until now. I calibrated the voltage with my Fluke and so on.

 

It was a fairly cool day out, high of 77 and low of 42 in Glendive, MT. In Great Falls it was a high of 67 and a low of 44. Im running 50hp injectors with an Airdog 200, my VP44 is 16psi at idle, and 10PSI at WOT. I had a lot of sustained 10PSI WOT. It was my impression this would not hurt the VP44, but now after reading I think it may have. However my code P0121 being the APPS does not coincide with this theory of the VP44 being hurt. I do have a new VP44 that I could put on, it's already been on and off the truck, so I'm not dying to install it again, but I could. I've done everything under the sun to raise my lift pump pressure at WOT besides clamping the return line like JL told me to do (I think it was JL). I still need to try that, which I think will work.

 

Any tips/tricks/banter greatly appreciated! I have to move in a month and buy a trailer so I already have a ton of other stuff to do, I wasnt hoping to be turning more wrenches on the truck now. Plus, I have to drive 2400 miles in the process of moving. So your help goes a long way.

 

Thanks

Edited September 19, 20177 yr by rogerash0

Have you checked for AC noise, that alone can cause lots of issues. Apps I would recommend getting from Timbo not autozone.

 Not sure what kind of help this will be but here goes. This I know, you have to get that fuel pressure up if you are going run it that hard. Does your AD not have a pressure regulator on it? My 165 does. The symptoms point to a VP but with no codes for the VP it does raise questions.

 I just went thru a fairly long bout of APPS codes, dead pedal, and engine surging mostly noticeable at idle but still present at speed and only visible on the scan gauge. Fast forward about 2 years and the issues were still present and on top of that I had started to get MAP codes on top of the APPS codes. I had already put a new Timbo apps and it did not fix anything. So one weekend I decide to put my old MAP sensor in and broke it in the process. So I put the old back in. Since that day I have not had one issue of dead pedal or surging or apps codes. That has been 3 months ago. I was however still getting 236 and 237 codes. I did replace the MAP sensor and now only see an occasional 237 code. I guess where I am going with this is the issue might be in the wiring. I am pretty well convinced mine is. I do not have a clue how this is all related other than the MAP APPS ECT IAT and oil pressure switch share the same ground. One bad sensor on the ground can make other stuff act up.

 Sorry for the ramble but hope it helps some anyhow. Others here are much more versed in the electrical things than I so lets see what they have to say.

 AC noise can and will contribute to this also as mentioned above.

Edited September 20, 20177 yr by dripley

My ac noise was .01v last I checked. I'm going to set the apps idle to .48v because I learned about the idle validation switch thanks to moparman. I know the writing rubbed off my switch, but I'm assuming it's IVS is .519v like others I've seen pictured.

 

I went with duralast because it's the Wells unit which had some video documentation posted on YouTube by wells that I liked. It's a magnetic holieffefct (sp) sensor that won't wear out.

DO NOT SET the IVS VOLTAGE for the OLD APPS SENSOR. You must set it according to Wells instructions.

 

Better yet get a Timbo APPS and leave all the voltage setting behind. There isn't any voltage calibration only bell crank angle. Timbo's APPS is a fully mechanical design and has ZERO electronics for the IVS. No logic chips nothing to fail other than the rheostat from wear. I'm over 6 year old and still going on a Timbos.

 

 

Wells uses a logic board like the Stock APPS for IVS setting. So you still dealing with electronics and electronics failure which like your previous sensor the P0121 was because the voltage and laogic state where invalid. So all it takes ia a little AC noise and your APPS sensor will fail as well. 

 

 

Edited September 20, 20177 yr by Mopar1973Man

I better not have to buy another APPS. I admit I had no idea the timbo was all mechanical. I thought it was similar to OEM but made by "timbo" for less $$$. Thanks the advice, I'll double check the Wells instructions and see how the voltages are looking.

 

Is there any truth to the APPS sensor voltage being higher or lower at max/min ranges affecting torque converter lockup? How hard it locks up and the time at which (rate of speed) it locks up at.

5 hours ago, rogerash0 said:

I thought it was similar to OEM but made by "timbo" for less $$$.

 

Here is a stock APPS...

 

Now a Wells Apps...

 

Still seeing logic chips electronic parts... Then flop over to Timbos...

 

 

Then there is the IVS contacts... No electronics for the IVS like Stock or Wells sensors use. The only thing Wells Sensors did was get rid of the rheostat and add a magnet and magnetic pickup for the position of the magnet. Still all electronic based to get the TPS signal and IVS signals. 

Edited September 21, 20177 yr by Mopar1973Man