Dead Pedal (I know it's been done to death but mine seems a bit different)

[TooTallCTD]

Hi all,

   First post on MoparMan's site but I have been reading this forum and many of his threads from diesel resource for quite some time. First things first a little background on the truck. The truck is a 2004.5 SLT, I do not have a lift pump it has been converted to in tank fuel pump, it's a CP3 injector pump system. I run a Edge CTS on setting 3, Timbo APPS installed last October, Transmission was rebuilt less than 2,000 miles ago, batteries were replaced at the beginning of October. If any other info is needed just let me know. Now down to the problem at hand when I went to pick my truck up after the transmission rebuild my batteries were shot so I bought 2 1000 CCA batteries to replace them and fired the truck up and left. Since I picked the truck up it was having intermittent dead pedal issues just as it did previously when the APPS when out so I reset the APPS and re-calibrated it. The problem went away for about 2 weeks, then on a trip back from Savannah the problem reappeared so upon returning home finally I reset and recalibrated the APPS again. The problem went away for about a week, I made another trip out of town this past weekend with 0 problems, but Tuesday morning I get in my truck to go to work and the dead pedal issue is so bad that I can't get out of my driveway. Every time I would attempt to accelerate it would throttle up and begin to accelerate but then drop back to idle and would do this up to 4 times in a distance of 8-10 feet. My fuel pressure is good as my gauges show 6.8k at idle and then appropriate numbers with the increase of RPM. My MAP readings seem to be good as I have been watching those and my Fuel Pressure since the dead pedal came back. So I stayed home yesterday and started trying to diagnose the issue, I started by checking my voltage on the APPS while moving the accelerator through it's range of motion. At "Idle" I was at .664v DC this is normal for the Timbo or so I've read, once engaging the accelerator it ramps up voltage smooth and steady all the way to 3.2-3.3v DC at this area my multimeter jumps out of range and doesn't read anymore. Once the accelerator reaches 3.4v DC my meter returns to reading the voltage and it continues to 3.83v DC just as smooth and steady as before. Also my meter isn't cheap it is a Fluke 77 and I've never encountered problems with it giving bad readings. Guys do I need a new APPS or is there another underlying issue I need to be concerned with? Thank you for your help in advance if any other information is needed just ask.

Also there are no codes other than Intake air heater #2 low voltage (P2607)

[Mopar1973Man]

First off double check your battery terminals and grounds. Being that your reseting the APPS muliple time tend to point back to failing alternator creating issues.

 

I would look at the alternator. I've run across a 3rd Gen truck with the same weird issues but it was the alternator feeding way too high of AC noise to the ECM and creating a bunch of APPS problems. After the alternator was replaced the APPS problem or dead pedal quit. The easiest thing to do is to pull the alternator and have it bench tested for AC ripple voltage. 

Edited July 1, 2019 by JAG1

[TooTallCTD]

Ok can I test for AC ripple voltage on the truck or is that something that I will have to pull it and have tested? I am mechanically inclined if it helps. Also I have checked both body grounds at the batteries and the block ground on the passenger side. I know there is another on the driver side just haven't found it yet. 

Edited November 1, 2017 by TooTallCTD

[TooTallCTD]

Ok so if I did my AC ripple test correctly I have a bad alternator. I flipped my meter to vAC and measured with the red lead on the battery terminal on the alternator and the black lead on the body ground for the passenger battery. I measured 1.9vAC! I was astounded at this reading which is why I wanted to confirm with you guys that I did my test correctly. I left both batteries connected and measured with the red lead on the battery terminal of the alternator and the black lead on the passenger side body ground as I said earlier. If this is the correct way has anyone encountered ACv this high before? Should I be concerned about my ECM being shot after a reading this high? Everything else on the truck behaves correctly except the dead pedal issue. No hard start in the morning or other symptoms of a bad ECM that I've read in other places.

 

I would also like to add that right before the dead pedal problem presented itself my car stereo speakers began cutting out at higher volumes. Not sure if this could be caused by high AC ripple voltage.

 

Edited November 2, 2017 by TooTallCTD

[Mopar1973Man]

3 hours ago, TooTallCTD said:

I flipped my meter to vAC and measured with the red lead on the battery terminal on the alternator and the black lead on the body ground for the passenger battery. I measured 1.9vAC! I was astounded at this reading which is why I wanted to confirm with you guys that I did my test correctly.

 

Yes, that was done correctly and yes that alternator is shot and doing serious damage to all the electronics on the truck I highly suggest you do not drive it also pull it off now have it bench tested to confirm also. Then when you replace to make sure to bench test the replacement alternator before you leave.

 

Start with the alternator replacement first then test again for dead pedal...

Edited November 2, 2017 by Mopar1973Man

[TooTallCTD]

Thank you for the quick response. I'll pick one up when I get off work and let you know how things go.

 

Had the alternator bench tested and it failed, the guys I use to rebuild my stuff said only a 2 hour wait to have it done. So instead of buying another and hoping it works I just had them rebuild mine 

Edited November 2, 2017 by TooTallCTD

[Mopar1973Man]

Make sure to have it bench tested again before you pay and leave again.

[TooTallCTD]

 

Couldn't figure out how to get rid of the quote boxes on my phone, but I should have bench tested it there. I had my wife pick it up since I had to go back to work for a bit. Once I got home I installed it and it still read 1.9vAC and the dead pedal was still there. Looks like I'm going back tomorrow. 

 

Edited November 2, 2017 by Mopar1973Man

[Mopar1973Man]

Cleaned your post up for ya... 

 

Something not right... Sounds like someone didn't do the rebuild...

[TooTallCTD]

It has new brushes and winding from what I can tell but I'm not sure if they did the diodes which would still allow the A/C noise, correct?

[Mopar1973Man]

Diodes are what filter the AC down to DC...

 

 

[TooTallCTD]

Gotcha. So not sure if you can give me an answer to this question, but with that much AC voltage what are the chances it fried my ECM? Also is that a picture of a alternator you had?

Edited November 2, 2017 by TooTallCTD

[Mopar1973Man]

1 hour ago, TooTallCTD said:

So not sure if you can give me an answer to this question, but with that much AC voltage what are the chances it fried my ECM?

 

Maybe... Depends on how long it has been high AC voltage against the ECM. Maybe, Maybe not. Simple way to test is to pull the field lead off the back and go for a test drive. If the dead pedal is gone then the ECM is fine. 

 

1 hour ago, TooTallCTD said:

Also is that a picture of a alternator you had?

 

Not mine... This was another member on the site that shared his experiences. That was also around a 2V AC measure on that diode pack..

 

I'm in the process of getting diodes ordered for the store on the site. So very soon we'll have rebuild kits for people at a fraction of the cost of replacements.

[TooTallCTD]

That sounds great! I'd love to have the rebuild kit to do it myself. I tried unplugging the field leads the dead pedal issue didn't go away completely but it was A LOT better. I actually made it halfway around the block before it did it. 

Edited November 3, 2017 by TooTallCTD

[TooTallCTD]

I just re-read the Tslaney thread about dead pedal. Thought I would mention that my truck doesn't have the dead pedal issue in park or neutral.

[TooTallCTD]

Just confirmed the only in gear aspect of mine as it ran all the way to WOT in park but didn't even make it to 1000 rpm before it cut out in reverse and in drive. 

 

Also with the dead pedal issue not going away completely with the field leads unplugged does that guarantee a fried ECM?

Edited November 3, 2017 by TooTallCTD

[TooTallCTD]

I'm really starting to get upset with my rebuilding guys. They keep arguing with me that the way I checked for AC voltage is wrong and that isn't how you check for AC ripple. They gave me another alternator to try so wish me luck. 

Edited November 3, 2017 by TooTallCTD

[TooTallCTD]

So not sure which of these fixed the issue but here we go. My rebuilders gave me another alternator (Bosch this time). But before I installed it I decided to change my battery cable end (they looked great but inside was a different story). So I bust the lead ends off the cables and inside was very very corroded so I use corrosion cleaner and a wire brush and clean them up. Hook everything back up and BOOM dead pedal gone everything working great! MoparMan thank you for all your help!

 

I will add that with the fan on high I'm getting a vibration in my pedals. 

Edited November 3, 2017 by TooTallCTD

[Mopar1973Man]

33 minutes ago, TooTallCTD said:

I will add that with the fan on high I'm getting a vibration in my pedals. 

 

I'm going to bet the fan squirrel cage is full of debris. 

 

36 minutes ago, TooTallCTD said:

So I bust the lead ends off the cables and inside was very very corroded so I use corrosion cleaner and a wire brush and clean them up.

 

I would consider replacing the cables soon this will only get worse over time. There is another thread on the site where a guy is replacing a main cable and crimping eys on and using military terminals.

[TooTallCTD]

Well I was greeted with the dead pedal issue again this morning for the first time in over a week. Alternator is good, grounds are good, terminals just replaced. I'm at wits end with this thing. 

 

Also the last time it gave the dead pedal issue was a cold morning. This is the first cold morning I've had since the "fix". What could relate this problem to cold weather?

Edited November 10, 2017 by TooTallCTD