Freightliner m2 accelerator

[fr8hlr521]

My `08 cummins truck (isc engine) has developed an issue when running using the pedal. All will be fine, then throttle response just disapears. No engine miss or anything like that, just as if I let off of the pedal. Then, if I lift from the pedal and go back to it, it is ok. Sometime check light flashes, most times not, then goes out again. Runs normally if using cruise. I am thinking throttle position sensor on the pedal...any other ideas?

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[tknight]

Clogging fuel filter maybe, or fuel screen?
Could be getting air in a fuel line?

 

[zorry]

I'd start with the TPS on the pedal.
Ot the wiring harness.
If there's a roller at the pedal, make sure it doesn't have a flat spot.

 

[Greg]

What trans do you have? I had the same problem last year, turned out to be Allison trans.

 

[fr8hlr521]

What trans do you have? I had the same problem last year, turned out to be Allison trans.

Had not considered that...it's an Alison 3000 6 speed auto...fuel filters, etc are ok. Am going to swap out the tps.

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[TeamHutch]

We had some similar symptoms and it was our fuel filters. Turned out speedco didn't change them when they said they did. Probably be the cheapest thing to change to start.

 

[fr8hlr521]

We had some similar symptoms and it was our fuel filters. Turned out speedco didn't change them when they said they did. Probably be the cheapest thing to change to start.

Agree...I watch Speedco like a hawk. Truck runs fine on cruise tho, up hills and down, for hours, so it's not acting like a fuel issue. No problems until I go to the pedal, and then only sometimes.

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[Dynamite 1]

I think you are on he rite track with the TPS but also don't leave out the possibility that the cruise switch or the high idle switch could be malfunctioning. Throttle is dead when truck is in high idle so that might be something to look at. Could be intermittently thinking high idle when running down the road there for killing throttle response !!

 

[Wolfeman68]

Try setting the cruise control at 60. Use the throttle to accelerate to 65 leaving the cruise on. Then release the throttle. See if the cruise will catch and maintain the 60 mph set speed.

Also, when the throttle drops out is the cruise control switch on? Not set, just on.

 

[fr8hlr521]

Thanks everyone for the replies! I changed the tps...same problem. After some checking on the cummins website I tracked down a loose connection on the ecu (the wire that supplies 5 volts to the tps...go figure!). Seems to be working ok now and will keep my fingers crossed over the next couple trips.

Again...thanks for the help and suggestions...will try to do the same back one day!

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