Humvee won't start

[motas2002]

Hello everyone. I am hoping the group can help me with this problem. I have a 1993 M1097 that I purchased at auction. I get it home and discover the injection pump is bad. I remove and replaced the injection pump with a rebuilt pump from DCP. I installed the pump and got it running while the intake manifold was off to make sure I was able to access the pump in case anything was wrong. My son and I put the manifold back on and reassemble everything else and now it will not start. I have verified that fuel is going to the pump, leaves via the return line, and that there is power to the top of the pump. When I crack one of the hard lines to see if fuel will come out as I had done previously to bleed the system, I get nothing. Am I over looking or missing something here? Thanks in advance.

 

[Retiredwarhorses]

DCP pumps are not just the worst rebuilders in the pump rebuilding business, they shouldn’t be in business period.
I have no less than 10 pumps sitting in my shop that can’t be used because they don’t know how to rebuild DB2 pumps.
Customer service doesn’t exist and a warranty claim will take months, that is if they don’t lose your pump.

 

[motas2002]

DCP pumps are not just the worst rebuilders in the pump rebuilding business, they shouldn’t be in business period.
I have no less than 10 pumps sitting in my shop that can’t be used because they don’t know how to rebuild DB2 pumps.
Customer service doesn’t exist and a warranty claim will take months, that is if they don’t lose your pump.

That is unfortunate to hear. Is there something that I can do to diagnose the pump if that is indeed the problem? Or perhaps another area to look at to rule out anything else? Thanks.

 

[Milcommoguy]

Hello everyone. I am hoping the group can help me with this problem. I have a 1993 M1097 that I purchased at auction. I get it home and discover the injection pump is bad. I remove and replaced the injection pump with a rebuilt pump from DCP. I installed the pump and got it running while the intake manifold was off to make sure I was able to access the pump in case anything was wrong. My son and I put the manifold back on and reassemble everything else and now it will not start. I have verified that fuel is going to the pump, leaves via the return line, and that there is power to the top of the pump. When I crack one of the hard lines to see if fuel will come out as I had done previously to bleed the system, I get nothing. Am I over looking or missing something here? Thanks in advance.

Power to the top...Good. Means nothing if solenoid is open, HI resistance, KAput. Did they re-build it for 24 volts? My free guess here. Double check for the 24 volts at 54 lead under load of solenoid. Pierce wire, tap in and test again.

IMO and history reading here....Based on the hi-lighted statement. Having fuel and running... Then NO fuel out at the injectors and not running ??? I would look to see (thinking cap on and backing up a few steps) What changed... That was easy. Kidding aside... Check the resistance of the cut-off solenoid. Should be around 25 Ohms. Could listen for the slight activation of solenoid by having STOP RUN START switch in the RUN position and hearing a click... when the connection is made on and off with the Packard connector. Doesn't mean the linkage is working... But it is a simple feel good test.

Still reading... quality control ? Did it crap out after one start. That would SUCK. Check the fuel cut-off solenoid and GOOD LUCK.

DOT DOT Dot means thinking. ??? means guessing, CAMO

 

[motas2002]

Power to the top...Good. Means nothing if solenoid is open, HI resistance, KAput. Did they re-build it for 24 volts? My free guess here. Double check for the 24 volts at 54 lead under load of solenoid. Pierce wire, tap in and test again.

IMO and history read here....Based on the hi-lighted statement. Having fuel and running... Then NO fuel out at the injectors and not running ??? I would look to see (thinking cap on and backing up a few steps) What changed... That was easy. Kidding aside... Check the resistance of the cut-off solenoid. Should be around 25 Ohms. Could listen for the slight activation of solenoid by having STOP RUN START switch in the RUN position and hearing a click... when the connection is made on and off with the Packard connector. Doesn't mean the linkage is working... But it is a simple feel good test.

Still reading... quality control ? Did it crap out after one start. That would SUCK. Check the fuel cut-off solenoid and GOOD LUCK.

DOT DOT Dot means thinking. ??? means guessing, CAMO

Thanks for the reply, I will try that when my second set of hands gets home in a little bit. As I have been poking around on some other threads I have developed another question. I thought I has sufficient fuel going to the pump but to double check, I pulled the line going to the back of the IP. With just the pressure of my thumb, I can keep the fuel in the line. If I don't close it off, it will squirt into the catch bottle I am using. Should there be more pressure then that or is my problem that the lift pump might be going out? Thanks.

 

[Mogman]

Thanks for the reply, I will try that when my second set of hands gets home in a little bit. As I have been poking around on some other threads I have developed another question. I thought I has sufficient fuel going to the pump but to double check, I pulled the line going to the back of the IP. With just the pressure of my thumb, I can keep the fuel in the line. If I don't close it off, it will squirt into the catch bottle I am using. Should there be more pressure then that or is my problem that the lift pump might be going out? Thanks.

If you have fuel coming out of the return fitting you have enough fuel pressure to run, the IP actually does not need any pressure in the gov. body to run it just needs to be full. the IP actually has a charge pump, they have been known to run with a bad lift pump but not well.
As Camo said make sure you have 24V with the IP connected, might even try to run a jumper from the alt to the IP, that is an easy way to hear the solenoid kick without anything else going on

 

[Mogman]

Sorry, was not paying attention, running the jumper to the alt works if you have a 100/200/400A alt, if you have a 60A alt you would need the run switch in the run position to get 24V at the alt.
remember to ALWAYS wait 90 sec any time you turn the run switch to off before switching back to the run position

 

[Milcommoguy]

Is your thumb calibrated to 3 to 6 PSI ?? I don't know ? So a guage would tell the real story. Flow too. Fill up a soda bottle half way in about 20 seconds of cranking. Now that's a test, LOL

A lot of testing IM bs O... should have been done shortly after receiving said truck. Starting at the fuel tank cap and thru every component to the IP input. It's a little time consuming... Clean, check, test, replace. Really not hard. Couple feet of hose, some clamps, a flush of the tank, new drain plug. pop in a new filter, Maybe a lift pump change out... $100 bucks and knowing one has a clean bill of health (pun) on the fuel system and on to the next PMCS testing.

Not pointing the finger here...BUT all of these new trucks / OLD, " Just picked up a sweet rig" I wonder about the "dealer prep" as it rolls off the trailer. Just needed batteries. OK, it could happen ?

CRAP fuel and rotted out fuel system with a quick "lets see if it runs" sounds like a trip to the bank for parts. Old grumpy / story teller here, learned to slow the roll with jumping into systems especially if has more that one part, like a hammer or _____________.

Something is wonkie along the fuel or control system. Going to have to walk it back, Sleep on it, test and turn a wench. Get dirty too, LOL

Not being the "Boots on the Ground" all one can do is take a shot on the internet.

A little high and to the left, CAMO

NOT saying anything about anyone. Just an observation of the more recent issues showing up with increased sales / interest in the hobby. PMCS is the word.

 

[motas2002]

Sorry, was not paying attention, running the jumper to the alt works if you have a 100/200/400A alt, if you have a 60A alt you would need the run switch in the run position to get 24V at the alt.
remember to ALWAYS wait 90 sec any time you turn the run switch to off before switching back to the run position

Meter reads 22v at the wire to solenoid at run position, 6v when it is off. Touch wire from alternator to solenoid and can hear audible click.

 

[Milcommoguy]

JUST a guess... Biased on data and NO red herring's... IP is not playing nice. Having just purchased it and with my luck, it's coming off and going for a ride back to TN.

You need fuel (a very little showing up at the injectors) when turning over engine. Try at a few more times with a wait time as not to burn out the starter in an attempt to purge the lines. Probably already done that? Fingers crossed and . Overall fuel in and timed VERY high pressure out. This is not a finger test here. Rag showing stinky / wet fuel and a few 20 seconds tries.

Not much you can do being a rebuild with a warrant tee, lol ?? If like you said it started and ran (how long?) and free flowing fuel out the top return line?

In my book something is a miss or a mess. IF... and that's a big IF that pump (quality control as stated) took a very big (starts with S) ___T DUMP and sheared the input shaft your DONE. Best case I am wrong. Stuck up linkage / metering valve clogged up. Spin the wheel.............

I would like to buy a vowel "I" and spin again, CAMO

 

[Mogman]

Sleep on it and try again tomorrow, fresh charged batteries etc.
It will not hurt to give it a few more tries before condemning it. be conservative with the starter.

 

[Milcommoguy]

No fuel at injectors... OK. You said that. Not a directly related question. Is the WAIT light and voltmeter tracking Glow Plug action? Just a follow along question from the peanut gallery. One is not there yet and don't know your outside temperature should fuel show up at injectors.

Pass the Cracker Jacks, CAMO

 

[motas2002]

So took another look at it after taking a break from last night. Here is what I have now. Meter reads 24v at the wire to solenoid at run position for both leads, 6v when it is off. Touch wire from alternator to solenoid and can hear audible click for both posts on top of pump. Bypassed lift pump with temporary electric pump getting fuel to the back of the injector pump. Now not getting anything coming out of the return line. Getting ready to start taking manifold off to start warranty process if I can't figure this out soon.

 

[Retiredwarhorses]

So took another look at it after taking a break from last night. Here is what I have now. Meter reads 24v at the wire to solenoid at run position for both leads, 6v when it is off. Touch wire from alternator to solenoid and can hear audible click for both posts on top of pump. Bypassed lift pump with temporary electric pump getting fuel to the back of the injector pump. Now not getting anything coming out of the return line. Getting ready to start taking manifold off to start warranty process if I can't figure this out soon.

It’s possible you sheared the internal pump shaft…you would have to open the top of the pump to get a visual

 

[motas2002]

It’s possible you sheared the internal pump shaft…you would have to open the top of the pump to get a visual

Would that be anything that I could have done on my end or a defect from the manufacturer?

 

[Mogman]

There is a check valve in the return fitting on top of the IP very small chance that is plugged, but would check anyway.

 

[motas2002]

There is a check valve in the return fitting on top of the IP very small chance that is plugged, but would check anyway.

I removed that to check function after I noticed no fuel coming out of the line. No fuel will come out with it removed also.

 

[Milcommoguy]

Back to my post #10. Cut-off solenoid clicking (proper activation??) No fuel at return line now. Lift pump substituted and still no flow? This is pointing to IP ?? but last hooray check for fuel at pump input. Never read that fuel filter was serviced. Any chance there are check valves along the flow paths? (tank or filter input)

Where the guys are going, one would need to put eyes on the internals to see if input shaft is turning, linkage and metering valve working, fuel in bowel, etc.
I am NOT getting a good feeling IF fuel is feeding IP.

Call first to get an OK to pop the top. If one opens it, one owns it? Might need a special security bit for that operation too.

Did you keep the box in came in? CAMO