Acceleration Drop Out

I am having an interesting problem regarding the acceleration of my 2004 Sprinter 3500 where the acceleration cuts out as I am depressing the gas pedal. No warning light comes on and the acceleration will kick back in if I push the pedal down further or take my foot off the pedal and re-press. When I say "cuts out" I mean the rpms return to idle or the speed of the engine turning if I am coasting.

This has been happening whether I am starting from a stop or on the freeway depending on the position of the gas pedal (it would seem).

When the acceleration cuts out and the engine returns to an idle rpm, if I shift to neutral there is no change in rpm. It is only when I wiggle the gas pedal that the throttle appears to kick back in and the van accelerates. The problem is intermittent and did not occur once when attempting to show the dealership repairman - happened a dozen times on the way to the dealership and at least a dozen on the way back.

If anyone has had a similiar experience I would appreciate any input. I do have some mechanical experience and have pulled a couple engines and transmissions in my time. I am a plumber by trade.

Thank you.

First let me extend you a hale and hearty welcome to the forum.

wagonerjd2002 said:

...
I am a plumber by trade.

Thank you.

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I won't hold that against you as long as you hike up your drawers before bending over.

If it hasn't been done already, the first thing I would do is remove the throttle pedal connector, inspect it for damage/corrosion and if it looks OK, re-install it on the throttle pedal assembly. Maybe spray it with a bit of WD40 before installing? It sounds like you may have something intermittant going on and connector plugs are often the culprit.

That, and what codes did the computer scan show? Good luck. vic

I would check your throttle position sensor.
You accelerator pedal in a Sprinter is not hooked to the engine in any way beyond electrical.
There is a sensor and a variable resistor of some sort that reads how much throttle you have applied and turns that into an electrical signal which is sent to the ECU (Engine Control Unit
(main control computer)).
The ECU transforms this signal into signals to the fuel injectors, the turbocharger and a whole bunch of other places.
The ECU is in control here, you just push the pedal and the ECU reads that and makes all the required changes.
So, the TPS (Throttle Position Sensor) and whatever other electronic/electrical devices are directly connected to the accelerator pedal would be the first place to examine.
Hope this helps,
Roger

Thanks for the responses. Sorry not to introduce myself to the forum. My name is Justin.

I believe that if you push on the service brake pedal, the engine goes to idle, so I would check the brake switch to make sure it's OK.

Okay. I removed the accelerator pedal assembly (3 screws and 2 wire harnesses). The throttle position sensor is located on the side of the assembly and held on by two very small torx screws. With these removed you have a sensor in your hand that is essentially sealed and cannot be further diassembled without cutting into the plastic housing. This unfortunately means no access to inspect the contacts or whatever is inside. This part cannot be replaced independently - requires replacement of the entire gas pedal assembly ($500 from dealership).

I checked the brake pedal per the last post and found something interesting along the way. Although depressing the brake pedal while accelerating would not cause the drop out problem, I did come to discover that my brake lights were not working properly. The right brake light was stuck on at all times and the left was out completely. I checked fuses and bulbs which were fine and then inspected the brake light switch located up and behind the brake pedal. I removed and reinstalled the wire harness and jockeyed around with the switch and its mounting. After this the left brake light came back on and both worked properly. I took the van for a 20 minute drive and the accleration problem did not occur once.

Coincidence? We'll see after a couple more days of useage whether the acceleration issue is gone. Meanwhile I am picking up a spare brake light switch ($26 from dealership) as I have had this switch fail me once in the past which created a problem where I could not shift out of park.

wagonerjd2002 said:

Thanks for the responses. Sorry not to introduce myself to the forum. My name is Justin.

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That's a very nice layout on your toolbed Sprinter.

I'm kinda envious.



I am an A/C service guy, and drive a 2004 cargo, with internal shelving, etc.

If I ever get it the way I want, maybe I'll post pictures of the innards.

Bob of QF said:

That's a very nice layout on your toolbed Sprinter.

I'm kinda envious.



I am an A/C service guy, and drive a 2004 cargo, with internal shelving, etc.

If I ever get it the way I want, maybe I'll post pictures of the innards.

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Thanks. I find it's nice not to have to go into the van to access most tools and material. Still, no roof can be a drag when it rains. I am in southern California and it doesn't rain very often.
Also, backing the truck up is a breeze as I can look through my back window and actually see directly behind me.

Just as follow up, it has been a couple weeks since I discovered I had a brake light switch issue in tandem with an intermittent acceleration issue. Resolving the brake light (brake light switch) problem has fully remedied the problem I was experiencing with the acceleration cutting out. Thanks to all for contributing their advice on this matter.

wagonerjd2002 said:

Thanks. I find it's nice not to have to go into the van to access most tools and material. Still, no roof can be a drag when it rains. I am in southern California and it doesn't rain very often.
Also, backing the truck up is a breeze as I can look through my back window and actually see directly behind me.

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<cue music>

"It never rains in California!"

wagonerjd2002 said:

Just as follow up, it has been a couple weeks since I discovered I had a brake light switch issue in tandem with an intermittent acceleration issue. Resolving the brake light (brake light switch) problem has fully remedied the problem I was experiencing with the acceleration cutting out. Thanks to all for contributing their advice on this matter.

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Part # 5101496AD(mopar #) if you have no ASR switch, with ASR(stability control) 001-545-87-09 mercedes #

Dang, the resurrection of an almost 11 yo thread! I did learn something though