Engine/Transmission (1998.5 - 2002) Dead pedal

[BMote]

Have seen many posts on dead pedal, but not too many positive fixes.2001 2500 4x4 stock engine
Initial startup every time goes dead pedal after short distance. Levels off at 1500rpm, no matter what you do with pedal. Corrects itself after awhile and will run all day, no problem. Just replaced vp44, no check eng light, no codes . Entered scanner results to computer and everything seems ok. Apps appears normal. Fuel pressure at vp44 of 15psi steady, Any thoughts??

 

[Road Dog]

I had a similar issue which turned out to be air getting into the fuel line (poor connection to the tank). The VP44 can go to limp and not throw a code. I think it faults a few times before notifying the ECM. You can hook up a 10' piece of clear vinyl tubing and drape it over the windshield wipers to watch for bubbles.

 

[BMote]

will check that out and see

 

[BMote]

Have clear fuel supply. Is it possible to have installed a rebuilt defective pump? Purchased from AMP in UT. Anyone have bad dealings from them?

 

[Sticks]

No check engine light, or no codes? Might be codes stored.

Might have to have a scanner hooked up that will tell you the throttle position commanded vs. actual.

 

[JR]

The symptoms you describe sounds just like the VP that went out on my former 00. Sticks is right might have to find someone with a scanner that runs live data to see what it's doing.

 

[Sticks]

A VP that won't rev past 1500 will have other symptoms along with it.

White smoke, hesitation. A WOT test is needed.

Engine at operating temps and either acting up or not. From Idle in neutral/park, go to wide open throttle and hold it. The RPM should increase smoothly, and relatively quickly all the way to redline (don't worry, this is what Cummins refers to as High Idle). Maybe a little puff of black smoke out the tail pipe when you start, then clear. If it does not do this, one of two things. Either the VP is on it's way out, or a fuel supply issue (pressure, air in fuel). Now if it does not hesitate or smoke, but revs slowly only to 1500, then it's in limp mode, and you should have a check engine light, or codes in the ECM.

Now on the flipside since you are describing symptoms while driving, and all other things being stock (no chip, programmer, performance add on's) you may have a turbo problem, and you should remove the intake hose and check the turbo - preferably while the engine is not running.

 

[BMote]

Have hooked up a SnapOn scanner and downloaded to computer program. Tps shows up as exactly as it should. Mirror image command vs actual.

No check engine light, or no codes? Might be codes stored. No codes show up. However, a strange 12v signal appears during warm up, and that is a shut off signal 12v to vp44. Have started engine and split this wire to disallow signal and no better results. Still dead pedal with split wire??

Might have to have a scanner hooked up that will tell you the throttle position commanded vs. actual.

 

[jkidd]

are you sure the woodruff key was not sheared or crushed when you installed it?

 

[PC12Driver]

Sticky MAP sensor? If the ECM doesn't see boost it won't add fuel. No codes would be set.

 

[Sticks]

are you sure the woodruff key was not sheared or crushed when you installed it?

Engine would not start or run if timing is off from bad install.

Sticky MAP sensor? If the ECM doesn't see boost it won't add fuel. No codes would be set.

Unable to verify, IIRC it would keep adding fuel until boost exceeds 20psi.

 

[PC12Driver]

Unable to verify, IIRC it would keep adding fuel until boost exceeds 20psi.

The MAP sensor is constantly used for fueling calculations. The ECM regulates the maximum fueling based on available air (boost pressure). This is the smoke control on a stock truck. If you step hard on the pedal and the MAP senses no/low boost, the engine will only get as much fuel as it can burn without making smoke. As boost comes up more fuel is allowed in at a balance that doesn't produce smoke, based on the MAP pressure. So if the MAP sensor is stuck when cold, the ECM would only see zero boost, thus limiting the available fuel. And because the voltage results for zero boost are within the "normal" range, no code would be set for a MAP sensor.

Put that Snap On scanner back on and see what the MAP results are while you drive and the engine is dead pedaling. Of course I should ask, did the dead pedal symptom show up before, right after, or sometime after the VP44 install? As with any component, yes you can get a bad one out of the box.

 

[BMote]

Took out the map sensor and cleaned itup and replaced in eng. Truck ran worse. Bought new Cummins sensor, replaced old one, and changed out fuel filter at same time.
Problems have disappeared, no more dead pedal.

 

[piperpilot3tk]

Awesome, gotta love it when the fix is an easy one!

 

[kirk02-3500]

02 3500 Cummins 89k miles

I am a new Cummins owner. Please don't laugh or judge at my ignorance.

I inherited an 02 3500 w/ a 6 speed manual from my late brother. I don't know much about the truck except I know it sat quite a bit. I actually drove it from KC, Kansas to Central IL several times pulling a goose neck and hauling other equipment home and the truck seemed to run great. Over the last couple of months, I noticed that the stock fuel pressure gauge in the cab was showing the pressure dropping slowly, like one trip would be 7 psi, the next trip would be 6 psi finally it slowly worked it's way down to 0 but still seemed to have plenty of power. I was pulling the trailer, the truck was running fine, but when I pulled in to town and turned on my street I got a check engine light and the dead pedal. I limped it the rest of the way home, 1 mile, unhooked the trailer, and parked. Idled fine, just no throttle. I went to the internet and this forum and started reading that I could have some costly repairs. I let it sit for a couple of days and checked the error codes. P1693 (I know there is nothing diagnostic about this one) and ECU P0121, P0602. I started it and pumped the pedal and it gave me throttle again and my fuel pressure was back up to 12-14 psi. I drove it to town thinking it was a fluke, check engine light went out, truck ran better than it ever has. On the way home, 1.5 miles out on a 20 mile trip, dead pedal again, check engine light again, but still 12-14 psi on the fuel pressure gauge.

Other things I have noticed about the truck since reading the forums:

EGT seems to peak when pulling the trailer at moderate loads. How can I drop EGT when pulling loads at highway speeds without slowing down and dropping a gear.
5-7 second turbo lag.
Stock exhaust, but rusted and missing halfway back. I intend to put 4" on soon after I get the dead pedal fixed.

I've read posts about the APPS, VP44, ECM, lift pumps, but looking to narrow this down for a starting point. Thanks for everyone's help.

I believe it has a Superchips 3705 Max Micro Tuner installed, but haven't actually hooked it up to verify. I found the programmer in the tool box.

 

[JR]

If you have a programmer hooked up and it's faulty it can cause a p602 code and driveability issues - simply shutting it off won't suffice you need to physically disconnect it to see if it's the problem.

Elevated EGTs can be attributed to poor fuel system Performance, get that issue ironed out and the egt and boost issues may correct themselves.

 

[Bob4x4]

Your egt's may be normal,what is the number and load.Dead pedal with no dtc's usually vp

 

[DenverPilot]

I think your VP44 is going. Probably exacerbated by the low fuel pressure it's been receiving. They don't like that. The pressure gauge is measuring pressure before the VP44 also, just in case as a new owner you're not aware of that. The performance of the lift pump. Not the VP.

Need hard numbers to know if your EGT is out of whack. With the programmer -- who knows what your brother was modifying or expecting for numbers -- but what number do you think is "high", to start off the conversation with?