MTVR underpowered with trailer

[abfisher1798]

I hitched up the M322 trailer to my MTVR this morning. I drove about 1/4 mile and pulled over because I was sure something was very wrong. The truck did not go past 15-20 mph with the pedal to the floor.
The trailer brakes were cold to the touch and appear to be working normally. I even cut the air supply and drove a few feet as a test and the brakes appear to be working fine.
I set the CTIS setting up a notch and no change.
I considered maybe that was normal for this setup, though I see others trucking along at highway speeds just fine (YouTube).
Am I missing something?

 

[NDT]

If you uncouple does the power return? I doubt it. Time to plug in the Cat ET and see why you have restricted power.

 

[MAdams]

Have you changed your fuel filters? Restricted air filter?

Try this, turn your CTIS switch off, then select 7-15 ton mode on the CTIS controller and see what happens. I towed a m322 with a 5 ton on it and could go 55mph

Sent from my SM-G975U using Tapatalk

 

[GopherHill]

Oh for a manual transmission. That sort of problem shows how much support is available on this site!
TomC

 

[Mustangsud]

We pull a civilian heavy flatbed with ours hauling 20-40,000 lb equipment and can run 55-60 all day. We've never experienced any of the issues you mention.

 

[TacMac2012]

Sounds like fuel filters, or something in the fuel system. Assuming it doesn't run perfect without the trailer, if it does, the trailer is the problem.

I have grossed about 70k with mine and it did fine, have since reflashed the ECM to 505hp and that really woke it up.

 

[abfisher1798]

I disconnected the trailer and the problem went away.

There is a parking(?) brake control switch near the front of the trailer; push to release, pull to engage. That switch pops out and stays out when the trailer is supplied with air. Push and hold it on and an odd clicking sound emanates from the rear. That’s how I drove it at first, but again there was no heat or smoke after a 1/2 mile drive.

 

[simp5782]

Hook your emergency air line back to the trailer from the truck or shop air and see if you have air coming out of the service side gladhand on the trailer. .

More than likely you do. You also probably have a bad check valve or tractor protection on your service delivery side on the truck allowing air to feed back to the truck inversion valve and apply your brakes on the truck.

You said you temp checked the trailer brakes but not the truck brakes.

This also happens with a bad tractor protection valve as it can divert air to the service side when air for the spring brakes is sent thru it.

 

[abfisher1798]

Hook your emergency air line back to the trailer from the truck or shop air and see if you have air coming out of the service side gladhand on the trailer. .

More than likely you do. You also probably have a bad check valve or tractor protection on your service delivery side on the truck allowing air to feed back to the truck inversion valve and apply your brakes on the truck.

You said you temp checked the trailer brakes but not the truck brakes.

This also happens with a bad tractor protection valve as it can divert air to the service side when air for the spring brakes is sent thru it.

Great info! I’ll start here and see what I find.

I’ll probably start another thread to ask if anyone knows the PN for the tractor protection valve. I think it’s a TP-3 style.

 

[simp5782]

Great info! I’ll start here and see what I find.

I’ll probably start another thread to ask if anyone knows the PN for the tractor protection valve. I think it’s a TP-3 style.

Yes it's a TP3. However there are tons of issues with the dual setup dash parking valves where they will bleed off and lock truck brakes up as well when using the trailer. @NewEra has this issue awhile back I believe

 

[abfisher1798]

Sounds like fuel filters, or something in the fuel system. Assuming it doesn't run perfect without the trailer, if it does, the trailer is the problem.

I have grossed about 70k with mine and it did fine, have since reflashed the ECM to 505hp and that really woke it up.

How did you do that? The reflash?

 

[abfisher1798]

Yes it's a TP3. However there are tons of issues with the dual setup dash parking valves where they will bleed off and lock truck brakes up as well when using the trailer. @NewEra has this issue awhile back I believe

What’s the alternative to the dual setup?
@NewEra, did you find a way around it?

 

[simp5782]

What’s the alternative to the dual setup?
@NewEra, did you find a way around it?

Make a cover plate to go where the dual valve is now install a single parking and trailer with the single mounting hole add a seperate air supply for the trailer side. Do not share with the parking brake.

Hook up the delivery ports as they are on the dual valve

 

[TacMac2012]

Mine wasn't a problem with the dual valve (although now I have ended up with a new spare, so I carry one in the truck). My problem was apparently someone in the military put a plug in the exhaust port of the brake valve assembly. I didn't think anything of it when swapping to a new valve, just swapped all the plugs/fittings, then had the same issue. So never hurts, take your panel off and make sure there is not a plug in the outlet labeled EXH.


As for the reflash, I have a CAT dealer that flashed it for me. Really woke the truck up, drives better empty and tows better too. You can mail it to him, I think he charges $450.

 

[abfisher1798]

Mine wasn't a problem with the dual valve (although now I have ended up with a new spare, so I carry one in the truck). My problem was apparently someone in the military put a plug in the exhaust port of the brake valve assembly. I didn't think anything of it when swapping to a new valve, just swapped all the plugs/fittings, then had the same issue. So never hurts, take your panel off and make sure there is not a plug in the outlet labeled EXH.


As for the reflash, I have a CAT dealer that flashed it for me. Really woke the truck up, drives better empty and tows better too. You can mail it to him, I think he charges $450.

I’m interested. How do I get ahold of him?