T800/CM2250 intermittent dead pedal/low rpm

[BRUDER01]

Heres an odd one-

CM2250 in a 13 T800.

When loaded rounding a corner with quite an aggressive lean (30mph) the pedal goes dead for about 3 seconds and the rpm's drop down into the 3-400 range for a blip and then everything comes back to life.

This will only happen in the two tightest corners of my 12 hr loop, its now happened 3 days in a row getting progressively worse. The first day barely noticing to today noticing a real issue.

No codes-

I inspected batt leads where they cross over or around any sharp points expecting a bare spot- found nothing (did not cut all ties and pull all looms apart yet)

Opened weather seal connectors going through fire wall, no moisture, no dirt.

Anyone have a similar experience? Suggestions on where to go next?
21,000Hr truck.

Thanks.

[tree98]

Follow the wires from the TPS and look for problems. Have someone shake the cab,wires, etc. While you monitor the TPS with insite, maybe you'll see it act up and you can trace it to a specific area.

[Bengy88]

(05-30-2023 )tree98 Wrote:  Follow the wires from the TPS and look for problems. Have someone shake the cab,wires, etc. While you monitor the TPS with insite, maybe you'll see it act up and you can trace it to a specific area.

Also unplug the tps and check for moisture. I’ve seen a lot of makes get moisture in the sensor from leaky cabs

[Rawze]

Could be a wiring issue, etc.. but also...

does the vehicle have a stability control?.. many trucks (part of the abs module or other system) do these days.

Also it sounds to me .. your post implies that your driving dangerously!. It only takes one rollover to kill someone with an 80,000 lb vehicle!.

[BRUDER01]

(05-30-2023 )Rawze Wrote:  Could be a wiring issue, etc.. but also...

does the vehicle have a stability control?.. many trucks (part of the abs module or other system) do these days.

Also it sounds to me .. your post implies that your driving dangerously!. It only takes one rollover to kill someone with an 80,000 lb vehicle!.

Thanks Rawze, will look into that.

Far from rolling over i drive quite slow actually, just implying the most aggressive lean the truck will see in a day- better choice of words could have been used.

[marek4792]

Rawze maybe onto something. If the yaw sensor (located on crossmember behind trans) maybe bad especially if you've gotten no fault codes, but if it does trip usually you'll get a yellow warning on the dash of such when it cuts the throttle.

[Tberg]

I had a truck doing something like this but only on hard accelerations. Was sensor supply 5 wire rubbed thru on front structure. Would ground out but for only a second when engine would flex. Motor mounts were also shot. Your accel pedal sensor supply is also tied into your def tank.

[Rawze]

(06-04-2023 )Tberg Wrote:  I had a truck doing something like this but only on hard accelerations. Was sensor supply 5 wire rubbed thru on front structure. Would ground out but for only a second when engine would flex. Motor mounts were also shot. Your accel pedal sensor supply is also tied into your def tank.

supply for the throttle pedal May or may not be tied to the def tank on a given truck. Depends on engine and truck. many are however tied to the coolant and tail shaft speed sensor, etc.

but you do have a good point about rubbed thru wiring causing intermittent issues like this. Seen that a lot.

here is a similar post about TPS issues...
http://rawze.com/forums/showthread.php?t...1#pid12551

Someone can always go onto quickserv.com (sign up for free usually) and look it up in the engine ECM wiring diagram, hat supply voltages, etc. go to what engine/aftertreatment components.

[votablesole5246]

you might need to calibrate the yaw sensor and the steering angle sensor using abs software. thats if it has a yaw sensor