Hello all, just joined the page so please forgive me if I don't do this right. 

 

I have a 98 2500 24v auto, and ever since I've owned the truck I've been having this issue but just never attempted to do anything about it until now. I've just rebuilt my transmission to hold 550hp, am looking to add a tuner but I know I should fix this before I try to add more power. I have read the forum here about adjusting the apps and numerous other forums and cannot find anything to specifically relate to my issue. 

 

To start, my issue is that when I plug in my OBD scanner, my APPS sensor was reading 8.6% at idle and 71.3% at wide open throttle. So, after doing some reading, I attempted a reset. I unhooked the batteries, let the truck sit for about an hour with the key on, and then turned key off, hooked batteries up and continued with the reset process. I have done this multiple times and it seems to correct the readings on my scanner to 0% at idle and 100% at WOT for about one day, then it resets back to the 8.6% and 71.3%. I am pretty positive my OBD2 scanner is reading correctly, I plugged it into my friends truck whose is identical other than his being the 2000, and his read 0% at idle and 99% at WOT. His is also bone stock but appears to have much more power than mine.

 

Next, I tried adjusting the apps sensor using the method Mopar Man posted here in the forum. I am pretty positive my APPS sensor is stock. My idle voltage was .49v, and the back of my apps stated the voltage should be below .569v so I adjusted the apps to .54v at idle (note, I did not loosen the apps screws and rotate it, I used adjustment screws like what was recommended). I then adjusted the WOT voltage. It was reading 3.63v, and while I couldn't find an exact voltage anywhere, I found a YouTube video Mopar Man linked to the adjustment forum that said it should read around 3.8v, so I adjusted it to 3.8v. Also, I checked to be sure that the apps did not have any voltage spikes or drops throughout the travel, which it did not. It was a nice smooth climb from idle to WOT. Now, after the adjustment was completed, I checked my APPS reading on my scanner and it's now showing that my idle percentage is 10.2% and my WOT is 74.3%. I've tried resetting it a few times and continues to default back to the 10.2% and 74.3%. 

 

I'm stumped. I've done all the research I can to try to figure this out without creating another post because I know there's thousands of them out there, but I cannot find anything that relates to my issue. Do I need to just replace my apps sensor or is something else wrong? Any ideas or suggestions would be greatly appreciated.

1 hour ago, Mopar1973Man said:

Got a box load of those left.

Thank you, the brand and part number is all I needed. I’ll do a quick search on Google and place an order! 
 

After replacing this, I should be good to send my ecm out for repair, correct? AC noise is down from .04 to .025 with the WT ground mod and I’ve done the PCM protection mod. Just doing this to try to bring it down more and ensure I have a good rectifier in it

I'll sell mine for 30 dollars. See what you can do. But it will be here I've got an entire case of these diodes.

On 8/12/2022 at 7:40 PM, Mopar1973Man said:

I'll sell mine for 30 dollars. See what you can do. But it will be here I've got an entire case of these diodes.

Sorry for replying to you so late, I took a two week vacation with the family and did not login here at all. I'm back now and ready to work on the second gen again lol.

 

So I ended up buying the diode off amazon for $20, the exact brand and part number you showed me in a previous post. I installed it in the alternator with new brushes and bearings from genos garage. I did the AC noise test again and it did not drop my AC noise at all, it is still sitting right around .025v. I did notice though that it does not spike above .030v anymore, it stays consistent at the .025v range. From what I read from other post it should be much lower after the new diode, correct? Or would you say its safe to run and I can finally send my ECM out to be repaired without risk of damaging it once I get it back. Also, I did notice on my scanner that my APPS sensor is suddenly reading correctly from 0-100% unlike the 8-71% before. I did not do a reset or anything, all I did was change the diode in the alternator and do the WT ground wire mod. 

 

Thanks for all the help with this issue I've had, sorry it took me a few weeks to reply. Hopefully this will be my last time posting in this thread and I can get that ECM rebuilt!!

3 hours ago, Zach B said:

it stays consistent at the .025v range.

Some people say less than 0.05VAC is passable but I like to see the voltage 0.030VAC or less.

When you buy from Mopar1973Man you are helping to support the site which is good.

 

MoparMan also has the Timbo APPS which is far more reliable, no adjustment required for half the price of the factory unit.

Edited August 26, 20222 yr by JAG1

On 8/5/2022 at 2:02 PM, Auto Computer Specialist said:

Your computer needs attention, wait to start light should illuminate right away. The computer needs to be rebuilt from top to bottom to solve all the issues stated plus a software update.

Reading these posts prompts a question.  My truck is a 2000 with standard transmission and 327000 miles. 
Based on this info would you say I’ve used up the ECM CYCLES? What does it cost to rebuild the ECM from top to bottom?

23 hours ago, DeepEastTexas2Gen said:

Reading these posts prompts a question.  My truck is a 2000 with standard transmission and 327000 miles. 
Based on this info would you say I’ve used up the ECM CYCLES? What does it cost to rebuild the ECM from top to bottom?

Is your lift pump powered by the ECM which is the factory set it up? Lift pump can go bad and damage the ECM so everyone is powering off the battery for the L.P., using the ECM power lead to trigger a relay. Relay has to contain a protection diode so no excess load going back thru burning up the ECM. IBMobile is the one who originally pointed this out about the need for a protection diode in the relay.

Edited August 27, 20222 yr by JAG1