M998 starts but stalls out while slowing down

[86humv]

Papaydsailor's truck is a civilian truck .

 

[albersondh]

Wont see a PMD on anything older than 94. I have never seen one on a mil HMMWV granted its been a while.... I think ECV's (M1151, 52, 65), and maybe even 1st gen up-armor M1114 may use these? PMD's fail for the exact same reasons that ESO's fail on DB2 IP trucks. Too much heat in the valley of the engine for electronics. The ESO on DB2 trucks is pretty reliable so its nothing to worry about. Most of the ESO hot restart issues I would see came from National Guard trucks with older 6.2's and the smaller ESO. Not too common to see a newer ESO fail but it happens.... Be VERY careful when swapping out the ESO, reuse all the plastic washers (insulators), in the exact same position they came out in. Or stand by to make smoke. Also, when you put the cap back on the IP make sure its seated correctly. I have never seen or done this myself and I personally think if you make this happen you need to drop the wrench, but it has been said that you can somehow put the ESO arm on the wrong side of the metering valve, holding the pump to FULL FUEL. Guess what happens when you start it like this. Best way to put the cap back on and ensure its on correctly is drop all three screws through the bosses on the cap. Then hook up 54A. Turn the ign to hot. Set the cap on the IP (good idea to use a new o-ring). When you start to push a screw into the IP you will hear/feel a click (complete ground for circuit 54A) and the cap should drop down and center itself. Start all the screws and then shut the ign off. Tighten all the screws, then stand head over the IP and pull 54A on/off. You should hear a nice crisp click. Good idea to listen to this click when the truck is dead cold before you pull the suspect ESO. Just to get an idea of how it should sound.

 

[Retiredwarhorses]

Papaydsailor's truck is a civilian truck .

Jeeeeze.....don't remember seeing any mention in the posts that the truck is a Hummer...wrong forum then.
while the 92-93 hummer H1 is as close to a HMMWV....you might have better luck on the humvee.net site

 

[vitamink]

regardless, all the information contained within is pure gold. I'm sure i'll need it down the road.

 

[Retiredwarhorses]

No one said the info was useless....the problem is its a must to know what your dealing with....thus the constant mentions of PMD failure...we are here to help, but certain facts are a must. Such as correct make, model and year.

 

[alpha1]

Hello everyone. I'm having issues with my truck and can't figure out what's the cause. to give you the entire description of how it started and what i did is; when i first had it it was fine, drove fine ran fine, no issues, then a short time late a few months maybe it stalled on red light , i would let it sit for 10-15 mins and start and drive for about 100 yards and the same thing till i got where i was going. few hours later that day it cut off leaving me blocking the intersection and it wouldn't start no matter how long i waited. well after i towed it home and changed the fuel pump(the one on side of the block) it turned out the strainer in tank was blocked, so i changed that too. after putting it all together i let it idle , before all the work it would smoke, white smoke and very thick, after it went down , but smoke is still there. i bled the system maybe a 100 times. then i took it for a drive and after 2 miles it stalled. i turned it off then started again and it ran and when i gave it full acceleration it stalled as if something was turned a switch off and killing it. it idles for hours no problem but with load it seems to just cut off. i took out the injector pump, the injectors and cleaned all of it, changed the return hoses on the injectors, changed the fuel filter ( the big metal cased filter that's on wire wall by driver). i start the engine at first it runs rough ( the first maybe 20-30 seconds, sometimes less and smokes quite a bit but not too much) then it smoothes out, still smokes but very light. yesterday i took it out and as soon as i got 10 feet from my house the idle fell way down and there was no throttle, no matter how much i pressed it there was nothing. and it stayed idling like that until i shut it off. i thought maybe air restriction so i took the air filter out then started again, and it was fine. so i parked it back. my question is , has anyone experienced anything like this? does anyone know what's going on?

sorry for the long text. and thanks in advance.

 

[Retiredwarhorses]

Have you installed a new or rebuilt injection pump? You say you cleaned the pump, that’s not going to fix anything internally wrong with the pump.

 

[alpha1]

when i opened the cap there was black guey things floating around and around the shut off solenoid. i drained the fuel and blasted the valley with carb cleaner then put vacuum on the inlet end ( the nipple on the back in the middle of the lines distribution for the injectors) and spun the pump by hand and whatever came out i blasted that off too with carb cleaner , then put it all back together and ran the truck.. I've been reading that there is an internal filter in those db2 pumps, is that true?

other then that i also have a hunch it is a bad injection pump.

 

[Retiredwarhorses]

Your pump is bad...you can’t clean that pump the way it needs to be cleaned without it being completely taken apart.
Then you have seals, o-rings etc that are bad, and more importantly a worn rotor head.
It also sounds as if your fuel cutoff solenoid is bad or shorted, thus the reason the truck just dies.
either way...not worth all the effort...put in a new pump.

 

[alpha1]

Your pump is bad...you can’t clean that pump the way it needs to be cleaned without it being completely taken apart.
Then you have seals, o-rings etc that are bad, and more importantly a worn rotor head.
It also sounds as if your fuel cutoff solenoid is bad or shorted, thus the reason the truck just dies.
either way...not worth all the effort...put in a new pump.

gotcha. thank you for the help!

 

[sallystrothers]

Just wanted to say, in case anyone else is searching on the topic, I was experiencing the stalling when letting off the throttle, both at a stand-still and while moving. It started about 1 month after changing the fuel filter, and I originally thought there must have been some air in the system somewhere, But today I opened the fuel drain spigot valve for the first time while the engine was running, and while the vehicle put out nearly a quart in 30 seconds, it had about 8 ounces of water in it. That was my problem. Works perfect now.