Dead pedal issues!!

[Mongoose]

Does not drop correct

Both...if I get in it and go it will do it and if I let it warm up.  And it does it under load and cruising. High rpms and low

Edited January 8, 2016 by Mongoose

[dripley]

I dont believe mine ever did it cold. It would do when ever it wanted to, towing or not, high or low rpm, it would just go to idle. I had to pull off the road and restart it one or more times and it would work just fine until the next episode. Took it to a shop and the only thing they found was very low fuel pressure, 5 at idle and almost none existent at WOT. I put a booster pump on near the tank and it cured my problem. Does not sound like your problem however, with the pressure you have.

[eddielee]

Okay, Describe exactly the dead pedal you are mentioning, is it like Dripley and Moparman are saying "idle only," or is it lack of throttle response "lack of power"?

And have you tried with fuel cap loose and venting?

Edited January 8, 2016 by eddielee

[Mongoose]

I'm cruising down the rpad or accelerating the the truck dies to a idle like I just let off the throttle then picks right back where ever  the pedal is. Sometime I will let off and floor it and there's nothing there and then it picks up throttle. Not lack of power or pedal. Just like the pedal isn't there.  I haven't tried the fuel cap but I've never heard a suction or vacuum on the tank when I open it. If the vent  were the problem would I loose fuel pressure?  Because I have no loss in pressure. Is there some way to check the vent?

Edited January 8, 2016 by Mongoose

[eddielee]

sounds like an intermittent short or broken wire somewhere beings all the symptoms, could be the idle on/off circuit cutting in & out.

I would triple check the Timbo apps for proper function and the apps wires to ecm for breaks and shorts.

[Mongoose]

Ok will do. I'll report back thank you

[eddielee]

Here is the info you should know about the APPS:

http://www.cumminsforum.com/forum/98-5-02-powertrain/54322-anatomy-apps-sequel.html

I usually use little safety pins to stick in along side the wires for testing.

 

Edited January 8, 2016 by eddielee

[Mongoose]

Is there a jumper wire I could put in just incase

[eddielee]

I find with this style plug that it is difficult to put a wire in the plug for a jumper.

The little gold safety pins can usually stuck along side the wire and tested for continuity with the plug unplugged to ensure connection.

Reconnect plug and leave two little safety pins facing away from each other so there is no contact. touch black to ground and red to either safety pin to see which has voltage.

diagrams are here:
http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/87-dodge-ram-turbo-cummins-24-valve-engine-wiring

what year is it?

looks like pins 2 and 6 in the plug are what you need to test.

2= idle off

6= idle on

Stick pin in 6 and test to ground on 20Vdc setting. without throttle there should be voltage and when the throttle picks up it should no longer be energized.

pin 2 should be opposite.

Intermittent issues are the most difficult to localize too.

Edited January 8, 2016 by eddielee

[Mongoose]

2001

[eddielee]

2001 diagram shows

pin 1 at ecm to pin 6 at apps/ idle on

pin 16 at ecm to pin 2 at apps/ idle off

pin 31 ecm power in at pin 5 apps

pin 32 ecm ground to pin 4 apps

pin 25 ecm to accelerator position to pin 3 apps

and pin 1 from apps appears to be ground to the potentiometer of apps attaching to other sensors like IAT, oil press, water in fuel and the MAP sensor

Edited January 8, 2016 by eddielee

[Mongoose]

So wiring is not my thing I'm not completely  helpless but I don't love it. Where do I start and what do I look for. I have a power probe , multimeter and test light. 

[eddielee]

using multimeter (DVOM) stick pin in 6 idle on/ with ignition on check for voltage on the 20V setting, you should see voltage at idle. Then turn throttle manually to 25%-50% (driving positions) and hold to see if voltage goes away and stays away, or comes back.

Pin 2 in that connector should be exactly opposite. Voltage begins when accelerator leaves idle and maintains Voltage without loosing Voltage.

I would expect to see ether 5V, or 12V at pins 2 and 6 in the apps. To be sure which you should see check the voltage of pin 5 in the apps.

Essentially what should be happening is the power comes in at pin 5 and switches between pins 2 and 6 to signal whether the idle is on (6) or off (2).

once the ecm sees the idle is off it checks for the position of the apps petentiometer at pin 5.

A potentiometer (aka: 'rheostat') is a variable resistor.

When you reset the apps by using the following directions the ecm figures out where to expect the voltage to be: http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/258-how-to-reset-calibrate-apps-sensor

Edited January 8, 2016 by eddielee

[Mongoose]

Ok awesome. Thank so much. I'll let you know 

[eddielee]

Have you ever performed the apps reset I just posted?

If not do this first and see if issues persist.

[Mongoose]

I did it for giggles today when I came into work I un hooked batteries and did the reset when I left. 

[dripley]

I experienced some similar issues that I heard described as bucking. In the throttle and it would cut out and come right back on at where ever the throttle was. It was very quick and made the truck "buck". Had this issue along with the dead pedal issues. My dead pedal issues only seemed to cure itself with restarts however. I even tried restarting the engine while moving if traffic allowed. sometimes it worked. Other times I had to sit for a minute or two.

I was a little slow on this response.

[JAG1]

Have you actually seen the Fuel pressure exactly on the instant this occurs?

 Also  disconnect the VP wire harness and check to see all the pins look good, fit tight, no corrosion or evidence of water intrusion. Then use dialectric grease on the pins and push back into place making sure it's all the way in. Check wires for any previous wire taps, weak points or loose wires going into the plastic connector housing.

[Mongoose]

14 hours ago, dripley said:

I experienced some similar issues that I heard described as bucking. In the throttle and it would cut out and come right back on at where ever the throttle was. It was very quick and made the truck "buck". Had this issue along with the dead pedal issues. My dead pedal issues only seemed to cure itself with restarts however. I even tried restarting the engine while moving if traffic allowed. sometimes it worked. Other times I had to sit for a minute or two.

I was a little slow on this response.

So what was your cure?  

[dripley]

49 minutes ago, Mongoose said:

So what was your cure?  

I took it to a shop and the only thing that they could find wrong was low fuel pressure. 5 at idle and almost zero at WOT. I did not have a fuel pressure gauge or know anything about fuel pressure at the time. I ended buying a BD Diesel booster pump and installed it on the frame rail at the tank. Ran that and the in tank pump for about 3 years or so and it never did it again, bucking or dead pedal. I always thought that fuel pressure was the culprit. All this was about 200k miles ago. Fast forward to about 6 months ago and I had an instance of dead pedal. Went to idle on the way to work. Pulled into a parking lot until the pedal came back and it has not done it again. Plenty of fuel pressure this time so not sure what caused it. I now have a FP gauge and a ADII 165 fuel pump, installed about 5.5 years ago.