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Hi all,
I am looking at a 2008 Humvee with the 6.5L TD with only 6500mi. I am wondering if many of the earlier problems like PMD relocate, crank breaking, head gaskets, cooling issues, cracked block, etc were alleviated when Navistar took over production of this motor? If so, what year did Navistar make the changes?
Thank you
Paul
Hi
The AM General engines were much better. Blocks were stronger as were the cranks.
The heads are much better as well....
The PMD issue was never really eliminated, but relocating the PMD to a cooler in an area that gets cool air pretty much keeps the issues to a minimum.
I assume the rig is the H1 Alpha ????
2008 Hummer M1152Quote:
Originally Posted by Robyn
Hummer H1, as Robyn suggests, or HMMWV M1152 (Humvee)? They are not the same. The HMMWV will not have a PMD to worry about, and will also have a 24V electrical system if not converted to 12V. If the engine is original to the year model, it will be the best of the best Navistar made, regardless of model. A civilian upfit Hummer could be anything, including an imported clone.
Sorry, meant Humvee 1152 & is 24V. Why does it not have a PMD to worry about? No idea there were clones, how would I know? ThanksQuote:
Originally Posted by DmaxMaverick
Unless it's been updated (downgraded, IMO), it should have mechanical fuel injection. No PMD.
Seller does state upgraded PCM, not PMD? Mechanical fuel injection is better for what reasons? I am taking a look at it tomorrow. Anything else to look for? Thanks!Quote:
Originally Posted by DmaxMaverick
PCM is Powertrain Control Module. Its function on a HMMWV M1152 would be minimal, if it has one (I don't know. Maybe?). I have no idea what might be "upgraded" about it, or what it did before it was upgraded. PMD is the Pump Mounted Driver (AKA: FSD = Fuel Solenoid Driver), only used on EFI engines. They have a higher relative rate of failure (results in a dead or unreliable vehicle), and it's electronic, both reasons it isn't used on military combat vehicles. The civilian versions were EFI during appropriate model years, having to meet emission standards, and they were only 12V. The EFI civilian model PCM can be electronically calibrated, or "upgraded", for higher power levels ("chipped" was the old term).
These trucks have the 4L80E Transmission
The mechanical injection pump was far better and was used in the MILITARY stuff
The DS4 electronic injection was too finicky and could not be trusted in a combat rig.....
The DB2 mechanical injection was used.
The HMMWV was equipped with a different Injection pump that could be fed a lot of different fuels...JP8 jet fuel was a common diet for these.
These rigs can burn kerosene in a pinch and just about any thin oil that's clean.
ATF will work on a warm climate.....
The plungers in the DB2 are harder than the civvy pumps to work with fuels that have less lubricity ...
Jet A can be used.....A bit of lubricant should be added to these fuels to stop excessive wear in the pump.
Peanut oil will work.
If you need to get OUTTADODGE IN A HURRY.....Pretty much anything that can burn will get things going (No gasoline)
I have seen guys mix a small amount of gasoline with motor oil to thin it out....Sketchy though....
Robyn: I'm curious as to what the military Humvees use as a transmission control with the mechanical pump and 4L80E. ???
The controls were the same as what was used on the 1992/93 6.5 trucks...Possibly the Mil stuff may have been a tad more robust.
Just a TCM is all.
There was still an ECM but it only controlled emissions IIRC.....
These modules were probably all in one box.....I am not familiar with the HMMWV and have no clue where the modules were located...
These rigs were pretty trouble free.....Other than the internal engine cracks .....
The DS4 was a non starter with the MIL rigs ...Waaaaaaaay too sketchy....