M1151 A1 funky behavior at the traffic light

[Tiwaz]

I am new at this so I'll try to explain the best I can (hopefully clearly enough):

Sometimes at the traffic light or EVEN IN REVERSE I feel the truck is in a weird gear because the engine gets bugged down to the point of sometime staling, ( I ride in "H") if I let go of the brake I feel it wants to take off at a speed that is faster than its normal behavior, sometimes in this "mode" i let go of the brake (w/o accelerating) and 5-10 yds later I feel the truck gets back into that 1st gear normal mode where i brake again and when i let go of the brake the truck advances SLOWLY. it does this about 20-25% of the times when I stop at the light. but again.... the VERY STRANGE thing is that it does this in reverse as well and putting it in neutral and back in D does not clear the problem.
I don't know if this is a commune issue since as I said I am a new Humvee owner, it's a 2007 6.5 TD, in fact I don't even know if i managed to explain clearly what's going on.

 

[Mogman]

Welcome to the SS forums.
It sounds like your torque converter is trying to lock up at inappropriate times.
The first thing you need to do is read the codes using the jumper described in this supplement and the trans light.
The trans light should be coming on when the run switch is turned to run but before the engine is started, you have to have a working trans light before you can start to troubleshoot your transmission..

 

[frauhansen]

Did you blink out the controll unit of your gearbox?

@Morgan.... thanks.. thats what i was looking for

 

[TNDRIVER]

I am new at this so I'll try to explain the best I can (hopefully clearly enough):

Sometimes at the traffic light or EVEN IN REVERSE I feel the truck is in a weird gear because the engine gets bugged down to the point of sometime staling, ( I ride in "H") if I let go of the brake I feel it wants to take off at a speed that is faster than its normal behavior, sometimes in this "mode" i let go of the brake (w/o accelerating) and 5-10 yds later I feel the truck gets back into that 1st gear normal mode where i brake again and when i let go of the brake the truck advances SLOWLY. it does this about 20-25% of the times when I stop at the light. but again.... the VERY STRANGE thing is that it does this in reverse as well and putting it in neutral and back in D does not clear the problem.
I don't know if this is a commune issue since as I said I am a new Humvee owner, it's a 2007 6.5 TD, in fact I don't even know if i managed to explain clearly what's going on.

I would suggest that you also check your transfer case linkage. Just because it says H on top doesn't guarantee its in H in the case. BUT HL should kinda show its self on any pavement. Doesn't hurt to look though. My 2 cents.

 

[Tiwaz]

Welcome to the SS forums.
It sounds like your torque converter is trying to lock up at inappropriate times.
The first thing you need to do is read the codes using the jumper described in this supplement and the trans light.
The trans light should be coming on when the run switch is turned to run but before the engine is started, you have to have a working trans light before you can start to troubleshoot your transmission..

Thanks a lot for posting the troubleshooting guide, I will familiarize my self with it and attempt to understand what is going on. For the time being the good news is that the trany light functions and that is a starting step in the right direction.

 

[Mogman]

Understand the TCM should never try to lock the torque converter in 1st or even 2nd gear IIRC, and of course never in reverse.
The last couple guys that had this issue at a stop had defective TCMs, it is also possible there is a short in the harness so you should follow the harness from the TCM to the transmission and look for places it might be pinched or frayed.

You can get a rebuilt TCM on the civy market reasonably cheap.

Because it is an intermittent problem it will be a challenge to troubleshoot, the TCM is probably not smart enough to know when it is massing up as to the TC lock so I would not expect any codes, but I have been wrong many times in the past.

One thing you can do is pull the cable from the TCM and run the transmission in limp mode and it of course should not have the problem of bogging down the engine you will just be limited to 2nd and reverse, again because of the intermittent nature of the problem this may prove inconclusive but IF it bogs the engine down with the TCM disconnected it is a mechanical issue in the transmission.

 

[Tiwaz]

Understand the TCM should never try to lock the torque converter in 1st or even 2nd gear IIRC, and of course never in reverse.
The last couple guys that had this issue at a stop had defective TCMs it is possible it is a short in the harness so you should follow the harness from the TCM to the transmission and look for places it might be pinched or frayed.
You can get a rebuilt TCM on the civy market reasonably cheap

Sure.... the thing is that, although I do my light to mid mechanic work on my Husqvarna bike and my wrangler I have no idea where things are in a Humvee, no idea where the TCM or its harness are so I will start this Saturday looking into this.

 

[Mogman]

Sure.... the thing is that, although I do my light to mid mechanic work on my Husqvarna bike and my wrangler I have no idea where things are in a Humvee, no idea where the TCM or its harness are so I will start this Saturday looking into this.

The TCM is in a protective box on the driver side rear floorboard, there is an unused connector on that box and that is where you put put the jumper in from A to E to get the codes.
This is one electrical job that you do not remove the battery cables first, if you do you erase the stored codes in the TCM.

 

[Tiwaz]

The TCM is in a protective box on the driver side rear floorboard, there is an unused connector on that box and that is where you put put the jumper in from A to E to get the codes.
This is one electrical job that you do not remove the battery cables first, if you do you erase the stored codes in the TCM.

ohhh.... that is great help, you just saved me a good 30 min reading, in fact if you tell me the specific page I should read in that manual you posted to get the codes, it would save me from reading the remaining 147 pages

 

[Mogman]

ohhh.... that is great help, you just saved me a good 30 min reading, in fact if you tell me the specific page I should read in that manual you posted to get the codes, it would save me from reading the remaining 147 pages

Look at page 60

 

[Tiwaz]

Look at page 60

Ohhh yes.... "things" are coming together, now I just need to know how to "Disconnect the "Glow Plug Controller" (step 2)

 

[Mogman]

When it says to disconnect the glow plug controller it is talking about the module (TSU) that is screwed into the water cross over on the front of the engine on the passenger side, has about 6 wires or so, you squeeze the connector to pull it off the TSU
You should always remove this connector any time you are doing any diag that requires turning the run switch on and off.
This helps keeping you from frying the glow plugs, under normal condition you MUST wait at least 90 seconds EVERY time you turn the run switch off before returning to the run position.
If you have a KD smart start box you must wait every time as disconnecting the TSU does not disable the glow plugs, the EESS box I speak of is under the dash to the left side of the steering column, you can read the label if you look under there.
ALSO reading the -10 operators TM should be mandatory for any HMMWV owner, the info about the 90 wait and a ton of other stuff that can save you BIG bucks is in there.
EDIT also if disconnecting the TSU works the wait light will only flash and not go through its normal cycle, or flash an error code and still not go through its normal wait cycle.

 

[Tiwaz]

When it says to disconnect the glow plug controller it is talking about the module (TSU) that is screwed into the water cross over on the front of the engine on the passenger side, has about 6 wires or so, you squeeze the connector to pull it off the TSU
You should always remove this connector any time you are doing any diag that requires turning the run switch on and off.
This helps keeping you from frying the glow plugs, under normal condition you MUST wait at least 90 seconds EVERY time you turn the run switch off before returning to the run position.
If you have a KD smart start box you must wait every time as disconnecting the TSU does not disable the glow plugs, the EESS box I speak of is under the dash to the left side of the steering column, you can read the label if you look under there.
ALSO reading the -10 operators TM should be mandatory for any HMMWV owner, the info about the 90 wait and a ton of other stuff that can save you BIG bucks is in there.
EDIT also if disconnecting the TSU works the wait light will only flash and not go through its normal cycle, or flash an error code and still not go through its normal wait cycle.

ohhh... al this brings out another point in this Humvee: the plugs warm light never cam on from the beginning so I wait about 20 seconds every time I want to turn the engine on (what a drag) I must say though.... I can see it flicking sometimes for a fraction of a second (really really quick) when I turn the lever from "Eng Stop" to "Run" I WOULD LOVE TO BE ABLE TO HAVE THAT LIGHT WORKING CORRECTLY

 

[Mogman]

ohhh... al this brings out another point in this Humvee: the plugs warm light never cam on from the beginning so I wait about 20 seconds every time I want to turn the engine on (what a drag) I must say though.... I can see it flicking sometimes for a fraction of a second (really really quick) when I turn the lever from "Eng Stop" to "Run" I WOULD LOVE TO BE ABLE TO HAVE THAT LIGHT WORKING CORRECTLY

Most likely ether the glow plugs are bad or the EESS (start box) is bad or both.
After you wait 20 seconds does it start right up with no smoke and run smoothly?
Do you see the volt meter bouncing around during this time but before trying to start?

 

[TOBASH]

Even with bad glow plugs, that light would light up assuming it’s functional. The implication is either the light is bad, or Mogman is correct stating that the protective control box versus EESS Smart box is no longer properly functioning.

 

[Mogman]

Even with bad glow plugs, that light would light up assuming it’s functional. The implication is either the light is bad, or Mogman is correct stating that the protective control box versus EESS Smart box is no longer properly functioning.

As I understand it some boxes will not operate "normally" if the glow plugs are bad.