Bringing back to life a 2009 HMMWV M1165A1 from GovPlanet - total newbie, please help...

[T9000]

Hi,

I picked up in April a 2009 6.5TD M1165A1 with about 7,000 miles on it (I am very excited about it and feel it is a retired hero who needs to be taking good care of) from GovPlanet and I have been battling a starting issue for a while. It has a hard time starting and it eventually starts after trying 2-3 times and I can drive it around as long as I keep the RPMs around 1,000 using the throttle lock, which could be related to the fact that the car it has been sitting around for the past 10 years, last time it had it's oil changed was in 2012, as it was marked on the filter.
Somebody local helped to change the engine oil/ filter, transmission oil, transfer case oil and flush the coolant system. I replaced the batteries with two new Group 65 AGMs with 775A CCAs.
There is still a slow leak coming from the fuel pump and/ or adjacent hoses which need to be fixed. I also put about 8oz of Hot Shot's Diesel Extreme in the gas tank thinking that maybe the injectors may be sticky or have residue/ contaminants after sitting for 10+ years and the engine does sound better and the throttle feels more responsive (maybe it's subjective) but it didn't help with the hard starting or once in a while stalling at normal idling and up and down RPMs changing on its own.

Here are the symptoms in more detail:

1. The engine idles and sounds good (video attached - tried to attach it but the site doesn't supports video files?), but at times it sound like it tries to stall, RPMs drop briefly and the car vibrates - something intermittent in the fuel system?
2. There is no smoke coming out, white or black
3. There is no blow-by
4. In order to keep it from stalling, when idling, I have to use the throttle lock set around 1,000RPM and sometimes it ramps to 1,500 by itself while idling then comes back down to 1,000 - again, maybe something with the fuel system?
5. Sometimes when it starts and I press the gas to get the RPMs up, then I begin to reduce the gas/ RPMs, the engine doesn't respond to the gas pedal and it
stops, even as I keep pressing it while it is still running to keep it going, but then I restart it and it runs - something in the fuel system?
6. Sometimes (noticed it 2-3 times) when the engine starts, the alternator doesn't engage (I believe that's also when the RPM meter stays at zero even as the
engine is running - I have it on video how the RPM meter drops to zero and comes back up while the engine was running without any significant changes in
the RPMs - the serpentine belt is running, but the alternator is not rotating at that moment and I can spin it by hand clockwise, but not counter-clockwise
(this is a separate issue I believe, but I list all these details as it may provide some additional info about what's going on).

Today I tried to replace the fuel filter and found that the top harness is not connected anywhere, please see attached pictures. I cannot find where it would normally plug in as there are no open connectors, however there is a cut wire coming from a harness down below, is that where it would go? Could this be cause for the difficult starting?

Please let me know if you have any questions or ideas of what to try?




Thanks so much!

 

[Mullaney]

Hi,

I picked up in April a 2009 6.5TD M1165A1 with about 7,000 miles on it (I am very excited about it and feel it is a retired hero who needs to be taking good care of) from GovPlanet and I have been battling a starting issue for a while. It has a hard time starting and it eventually starts after trying 2-3 times and I can drive it around as long as I keep the RPMs around 1,000 using the throttle lock, which could be related to the fact that the car it has been sitting around for the past 10 years, last time it had it's oil changed was in 2012, as it was marked on the filter.
Somebody local helped to change the engine oil/ filter, transmission oil, transfer case oil and flush the coolant system. I replaced the batteries with two new Group 65 AGMs with 775A CCAs.
There is still a slow leak coming from the fuel pump and/ or adjacent hoses which need to be fixed. I also put about 8oz of Hot Shot's Diesel Extreme in the gas tank thinking that maybe the injectors may be sticky or have residue/ contaminants after sitting for 10+ years and the engine does sound better and the throttle feels more responsive (maybe it's subjective) but it didn't help with the hard starting or once in a while stalling at normal idling and up and down RPMs changing on its own.

Here are the symptoms in more detail:

1. The engine idles and sounds good (video attached), but at times it sound like it tries to stall, RPMs drop briefly and the car vibrates - something intermittent in the fuel system?
2. There is no smoke coming out, white or black
3. There is no blow-by
4. In order to keep it from stalling, when idling, I have to use the throttle lock set around 1,000RPM and sometimes it ramps to 1,500 by itself while idling then comes back down to 1,000 - again, maybe something with the fuel system?
5. Sometimes when it starts and I press the gas to get the RPMs up, then I begin to reduce the gas/ RPMs, the engine doesn't respond to the gas pedal and it
stops, even as I keep pressing it while it is still running to keep it going, but then I restart it and it runs - something in the fuel system?
6. Sometimes (noticed it 2-3 times) when the engine starts, the alternator doesn't engage (I believe that's also when the RPM meter stays at zero even as the
engine is running - I have it on video how the RPM meter drops to zero and comes back up while the engine was running without any significant changes in
the RPMs - the serpentine belt is running, but the alternator is not rotating at that moment and I can spin it by hand clockwise, but not counter-clockwise
(this is a separate issue I believe, but I list all these details as it may provide some additional info about what's going on).

Today I tried to replace the fuel filter and found that the top harness is not connected anywhere, please see attached pictures. I cannot find where it would normally plug in as there are no open connectors, however there is a cut wire coming from a harness down below, is that where it would go? Could this be cause for the difficult starting?

Please let me know if you have any questions or ideas of what to try?


View attachment 850616View attachment 850617

Thanks so much!

.
Welcome to the outfit!

Happy to hear that you changed the oil and filters. The fuel in the tank has been there for several years most likely. These trucks sit out in the desert (in your part of the country) for years while the military decides on their final disposition. Military JP8 that could be in the tank doesn't "grow the green crud" that would have been growing in the fuel tank otherwise.

You definitely need to change the fuel filters.
You really don't want to clog up the injection pump (with rust in the tank or other creeping crud).


Hopefully some of the other guys can chime in on the wiring because I don't really know what the unplugged wires are all about. The Technical Manual (free download here) has the answer. Straight up logic says if it was critical to running - the truck wouldn't have cranked.

The WAIT light in the left corner of the dash... Is that working - and are you waiting until it turns off? (also in the TM - the "-10" is what you need most at the moment). Not trying to be a butthead, just trying to point you in the direction of making use of the books...

 

[T9000]

Please no worries about being a "butthead", I totally understand what you mean. I have been trying to learn my way around the manuals and did find the fuel filter part, but so far without any info about where the sensor cable attached on top would connect and I will keep looking.
The fuel tank looks clean from the outside without any stuff hanging at the bottom, I was going to completely empty it and run diesel thru it with the bottom drain screw open just to let everything inside drain out, but then I read somewhere on the forum that the fuel pump may stop working if it's losing the vacuum? So I didn't do the full tank drain yet.

Yes, I do wait 7-10 seconds for the yellow light to go off before cranking it

 

[Action]

You can only spin the alternator one way by hand, because there is a clutch in the pulley. Kind of like a bicycle turning the pedal forward turns the back tire. But if you stop the pedals, the tire can spin freely.
the alternator doesnt kick in for roughly 30 seconds after starting. The tach gets its signal from the alternator.

 

[T9000]

Thanks for confirming that the tach is getting its signal from the alternator. I believe there is something going on with the alternator clutch because sometimes the tach drops to zero while the engine is running well past the first 30 seconds and then it recovers.
Another way that I can tell the alternator is not running is when the battery meter stays closer to yellow instead of being on green, but that's a different issue I think, unrelated to the hard to start + up and down RPMs with the occasional stalling.
Someone said that maybe there is air in the fuel line? Or that the fuel pump is not working right?

 

[T9000]

I uploaded a video where you can hear how the engine is trying to stall in the beginning, after which I run the RPMs high then release it and let it idle, the gauges are in the normal range:

HMMWV 6.5TD Engine Sound

Engine sounds like is trying to stall in the beginning part, then I press the gas to increase the RPMs and let it idling again. All gauges read in the normal range.

rumble.com

 

[86humv]

Thanks for confirming that the tach is getting its signal from the alternator. I believe there is something going on with the alternator clutch because sometimes the tach drops to zero while the engine is running well past the first 30 seconds and then it recovers.
Another way that I can tell the alternator is not running is when the battery meter stays closer to yellow instead of being on green, but that's a different issue I think, unrelated to the hard to start + up and down RPMs with the occasional stalling.
Someone said that maybe there is air in the fuel line? Or that the fuel pump is not working right?

If the clutch pully fails...it still works as a regular non-clutch pully.
If voltage drop...probably the regulator.

 

[Bill Nutting]

Welcome to the hobby! When I bought my M934 from GP, it had been sitting for eight years . We prepped the truck for the 1,000 mile drive home. It ran pretty bad for the first couple hundred miles. As we kept filling it with fresh fuel and additives it ran better and stronger. By the time we made Michigan, it was running up hills without slowing down much at all. I would suggest putting fresh fuel in it then take it for a few hundred mile road trip. If your nervous about that, ask a friend to follow along in a chase vehicle…

 

[Action]

If you remove the tank drain plug, be sure to have a new one to put back in.
There is an access cover that can be removes in the bed to get to the top of the fuel tank. Maybe you can remove that and then the sender to look inside the tank. The access cover may be under the a/c evaporator between the rear seats.

 

[NDT]

Your injection pump is dying, get it remanufactured. The cut wires on the filter are inconsequential, they are for the diagnostic connector. The alternator might be getting intermittent sense voltage, that is the feed in the small gauge wire.

 

[Action]

And just curious...why were you revving it up to 3500 rpm?

 

[Action]

the engine harness routes through that clamp in the top right of this pic.

 

[T9000]

And just curious...why were you revving it up to 3500 rpm?

The way it runs it feels like something is intermittently sticking or something is getting in the way and thought if I push the gas thru faster it may improve the situation since the it has been sitting for so many years, I am an electrical engineer, not mechanical and this is the first car I am actually trying to figure out And thank you for all your input,

 

[T9000]

the engine harness routes through that clamp in the top right of this pic.

Yes, I removed the engine harness in order to get to the fuel filter as it is very cramped behind the alternator. I am hoping to replace it tomorrow, it is not much space to get to the screws and the two fuel lines clamps screws heads are facing towards the back of the dashboard. Is there any easier access to the fuel filter by removing the dash? (it looks like the clamp screws were tighten from that direction? (sorry if I am asking any dumb questions, I am just beginning to get my mind around this - my kids are happy when it is running and we drive around the neighborhood, but not so much when I get sucked in these issues and don't spemd time with them
Thank you!

 

[T9000]

Your injection pump is dying, get it remanufactured. The cut wires on the filter are inconsequential, they are for the diagnostic connector. The alternator might be getting intermittent sense voltage, that is the feed in the small gauge wire.

Ok, I understand that the cut wire could be for some diagnostic/ factory/ field test/ diagnostics, but how about the 4 wires connector coming from the top of the fuel filter? I saw in a YouTube video where they were replacing the fuel filter that same connector was plugged in a harness.
I read somewhere that it may be a fuel pressure sensor but didn't find it in the manual yet,
Thank you!

 

[T9000]

If the clutch pully fails...it still works as a regular non-clutch pully.
If voltage drop...probably the regulator.

The alternator charges the batteries OK, the mean voltage is about 28.5VDC with a ripple of 2.5V (please see scope capture, the sampling is in peak detect mode which shows the worst min/max deviation). Is there a way to adjust the alternator voltage? I did not see the adjusting pot like some other models have.

 

[Action]

There are 2 bolts inside by the end of ebrake handle(when down). Those hold the fuel filter to firewall. It is easier to get the canister out if you remove the 2 hoses at top, from inside the truck.

 

[Bill Nutting]

Yes, I removed the engine harness in order to get to the fuel filter as it is very cramped behind the alternator. I am hoping to replace it tomorrow, it is not much space to get to the screws and the two fuel lines clamps screws heads are facing towards the back of the dashboard. Is there any easier access to the fuel filter by removing the dash? (it looks like the clamp screws were tighten from that direction? (sorry if I am asking any dumb questions, I am just beginning to get my mind around this - my kids are happy when it is running and we drive around the neighborhood, but not so much when I get sucked in these issues and don't spemd time with them
Thank you!

You’re not asking dumb questions. That’s not a problem here. Helping new members is what we do. At some point you are going to see that you landed on one the best sites for any hobby. I don’t know much about your HMMWV so I won’t be much help except to tell you that you are getting real good advice from folks that do!
I’m glad you are changing the fuel filter. You may have to do it again after you get some miles on it. when these trucks sit for some years it can take a while to get things loosened up and working properly. Bouncing down the road may free up some crud in the fuel system. You are doing the right thing by changing filters.
I like my charge voltage around 27 volts. That is measured with a digital volt meter. The two volt ripple might add one volt at the peak. Putting a scope on it was a good call. I’ve never thought to do that ( I will now).
I hope someone has a trick for removing the fuel filter that doesn’t require removing the dash!
How are the breaks? First we make them stop, then we make them go, then we go after the small stuff…
Spending this time now will ensure you have lots of SAFE fun later. Press on.

PS. Thanks Action! You were answering the fuel filter question at the same I was asking about it. This site has MIND READERS!

 

[Sigi]

Your symptoms are consistent with air in the fuel supply. You also mentioned a fuel leak. That is where air could enter the fuel supply. I'd fix that and change the fuel filter. Read up on how to bleed the fuel system.

 

[Retiredwarhorses]

The M1165A1 REV’s didn’t sit like the M1123’s, these trucks were in service only a few years ago.
I’ve found no contamination in the fuel, in fact, of all the REV’s I own “4” and have had come through the shop,they all have had JP8 in the tank. Your issue is fuel starvation…you need to go completely through the system from tank to injection pump.