Random dead pedal

[Dave f]

Hi guys, I understand this topic has been beat to death but I have had the following issues with my 98 2500 24v. 

Over the last two years I have had random codes pop up with no performance problems (low voltage related to apps sensor) had them cleared 2x about a year apart. Did hours of research and the common thread seemed to be a failing apps sensor (no dead pedal up to this point)

So i bought a new bell crank assy to have on hand in case. About a week ago it happened dead pedal, when I pulled to the side of the road it went away. So when I got home I replaced the bell crank/apps assy asap. Been driving it for a week without issues yesterday when I was decelerating to a stoplight it happened again for just s second. Any ideas (vp44 was replaced about 3 yrs ago still has stock lift pump as far as I know).

[dripley]

My experiences with dead pedal have been any thing but the APPS sensor. My first experiences l took to a shop and the only they could find was very low fuel pressure from the lift pump. I put a booster pump on and the problem went away. That was 13 years ago.

The next instances started about 5 years ago. Much worse than the first time. I fougth that for 2.5 years. I did find a bad splice on the 5v power to the sensors, but I also got in and cleaned up my electrical system. New cables, cleaned all the grounds, checked electrical connections. I also did a ground modifacation listed here as WT's ground mod. The problem stayed with for a while on and off and finally disappeared after all cleaning up the electrical system.

 

Since you bought a whole bell crank assembly I have to assume it came with a factory style sender. Did you set voltage on it after install?

 

And for future reference you only have to replace the sender and not whole bellcrank. You have aftermatket to do that. The aftermarkets are better. Pretty much plug and play. I have 500k on the original bell crank.

Edited April 26, 2020 by dripley

[Dave f]

I've been keeping an eye on the fuel pressure religiously since I 1st got the truck about 9 years ago. When I 1st got it I turned up the tuner and cooked the injection pump the previous owner installed the tuner and didn't upgrade the lift pump unbenounced to me expensive lesson lol.( at 18 psi at idle and not under 10 psi off idle) I just learned of wt's ground mod today and will be doing that shortly. Alot of the posts I read on other forums led me to believe the apps sensor could be the problem. And yes I believe the apps sensor is oem. I bought the whole assy because I was told by the mfgr the voltage was preset and didn't need to adjust it. That was what the insert that came with the part said. Sounds like I need to do that and some ground cleaning work and maybe a lift pump. I've rebuilt just about everything on my power wagon but these modern diesels are much different critters.

Thank you for your imput, still learning with the modern systems if it's got a carb I'm all over it but kinda lost on the others

Any advice on an aftermarket lift pump and what size I'm running a edge juice tuner and would like to use the towing settings haven't used it since I fried the injection pump 

[dripley]

18 psi at idle is pretty good for an oe style pump. I only run 19 on my AD but only have a 4 psi drop at WOT. Is your lift pump mounted just behind the fuel filter on the block?

[Dave f]

Any advice on an aftermarket lift pump and what size I'm running a edge juice tuner and would like to use the towing settings haven't used it since I fried the injection pump 

Not positive on the location I was told by the mechanic that replaced the injection pump so I would assume it was on the block but I'll have to check tomorrow. Been looking at the reviews on the bd and fass 100 gph models

With lots of opinions both ways I'm looking at around 360 hp max. Was also looking at some of the mechanical pumps as well but not sold on belt drive.

[dripley]

I am running an AD 165 on mine. It is way overkill for me even for what you want. I have had 2 pump failures in the 9 years I have had it but they replaced both under warranty. This last is a 4g pump so maybe they got the bugs worked. The mechanical I dont know about. Quite a few members here have them and are very happy with them. I might have gone that route back then had I known. They seem to holding up well for others. Belts dont seem to be an issue for anyone. Electric, a 100 or 150 is plenty.

[Dieselfuture]

All good advice above. Wish you would have got a timbo apps, even though you may not needed. If I would have researched mechanical lift pumps more before I got a fass I would have went with that. Not that fass Isn't doing the job, i just have my reasons for it. If you do go mechanical it would be nice to have another spin on filter, something like fass and air dog come with. You won't fry VP with edge, it's the lack of fuel pressure, ac noise and poor lubricity that kills them. 

[Blueox01]

I had a similar issue, not so much a dead pedal, but would sound like the exhaust was plugged, it was the VP44, electronics went out.

[Mopar1973Man]

Might look into doing the W-T ground wire mod. AC noise can do weird thing to foul up performance of the engine and computers. 

 

On 4/25/2020 at 10:33 PM, Dave f said:

Any advice on an aftermarket lift pump and what size

 

I'm also running AirDog 150 than was upgrade to AirDog 165. My first pump motor last for 250k miles, second was 3G motor and failed in 7k miles. Then Upgraded to 4G pump motor and already past 100k miles on this pump motor. I'm feeding Quadzilla tuner, HX35/40 Turbo (60/60/12) and 7 x 0.010 @ 320 bar injectors and only drop about 4 PSI of pressure at WOT. From 18 PSI down to 14PSI. Never trips my ISSPro gauge warning light set for 13 PSI.

 

Edited May 1, 2020 by Mopar1973Man

[Dave f]

Ok, guys thanks for all the responses. I'm attempting the w-t ground mod 1st however after looking at the pics for the procedure I'm kind of confused on the alternator side of the project there is a kind of junction block on the alternator that contains 4 wires (2 large and 2 small) on the 2 large I assume one is the power wire since it connects to the alternator  + stud and the other is a ground that connects to the frame of the alternator. Now the small Guage (blue and green) wires are field winding wires I assume  do I remove the whole thing  if so how do I know where the small Guage blue and green wires go I didn't see anything dealing with it in the pics. Or am I just adding a 2nd charge lead to the aux battery.

Edited May 9, 2020 by Dave f
Confusion

[Dieselfuture]

On 5/9/2020 at 11:24 AM, Dave f said:

Ok, guys thanks for all the responses. I'm attempting the w-t ground mod 1st however after looking at the pics for the procedure I'm kind of confused on the alternator side of the project there is a kind of junction block on the alternator that contains 4 wires (2 large and 2 small) on the 2 large I assume one is the power wire since it connects to the alternator  + stud and the other is a ground that connects to the frame of the alternator. Now the small Guage (blue and green) wires are field winding wires I assume  do I remove the whole thing  if so how do I know where the small Guage blue and green wires go I didn't see anything dealing with it in the pics. Or am I just adding a 2nd charge lead to the aux battery.

I'm pretty sure I have big charge wire that will go to passenger side battery through a 150a reset broker, then a small plug blue and green, you need to put a fuse on blue to protect pcm, this is @Mopar1973Man mod that already saved few pcms.

What year is your truck maybe someone put a different alternator on yours

[Dave f]

It's a 97.4 24v. I believe it's a stock setup as I've replaced the alternator 2x and everything matched up correctly

[dripley]

4 hours ago, Dave f said:

It's a 97.4 24v. I believe it's a stock setup as I've replaced the alternator 2x and everything matched up correctly

You mean a 98.5?

[Dave f]

Yes, sorry fat fingers syndrome. Lol

[Dave f]

Ok, I was finally able to get the codes read and they are as follows

P0121 throttle/pedal position sensor a circuit range/performance

P1389 no ads relay output voltage at pcm 

P1693 

P0121 a 2nd time

Can anyone explain them for me

 

[wil440]

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/obdii-error-codes_94/

[Dave f]

Ok guys new possibly urgent issue, after completing the w-t ground mod procedure I removed the apps/bell crank assembly cover to check the sensor voltage, BOTH of the adjustment set screws fell out of the cover. How do I re-adjust them when I put them in. there is no voltage tag on the back of the apps sensor I assume it's due to being replaced as a complete assembly could this be the reason for the random dead pedal problem

[Mopar1973Man]

I would just find screws of like size and thread and just set the idle position for what you need on the APPS sensor. Remember what type your adjusting for. Never adjust a stock for the voltage on the tag. ALWAYS below by 0.2 volts is safe. On a Timbo's APPS you have to adjust for the rise of voltage then back off 1 full turn. Max throttle screw needs to be enough to keep it from throwing a hi volt code. 

[Dave f]

Thank you, I read that in one or your previous posts in some of my research this morning. I was able to retain the screws and returned it to napa who replaced the whole assembly. After which I made a 20 mile test drive with no issues so far and the code light is out for now. So I'm hoping the problem was a faulty part if/when it happens again I'll get a refund and buy a timbo. Trying to get an appt to upgrade the lift pump they are 3 weeks out right now.

[Dave f]

UPDATE,  after nearly 200 miles dead pedal problem is still gone yaay. Still kinda nervous about fuel pressure with the stock lift pump tho my edge juice w/attitude shows 17-18 psi at idle and can draw down to 10-11 psi when I hammer the throttle on a good uphill incline in stock mode. Is it accurate or does it appear the stock  lift pump may be weak. Just want to know if I have a little time before I can get it replaced.