Bad injector pump but run fine once started?

[1 Patriot-of-many]

I'm stumped, about the only test I haven't checked is the cranking rpm, but it turns just as fast as my M1009. Can I have a bad injector pump if it runs fine after starting with ether? (Yeah I know).

If I use ether it will start immediately and run all day, no problems.
I have good fuel pressure past the filter. I have no fuel to the injectors when cranking.(If it's a prime issue, why does it start with either and run no problems) Glow plugs are new and I'm getting 17V or more to the glow plugs, wait light comes on for about 7 seconds then goes off. Voltage meter drops as it should.

I've checked Fuel solenoid, clicks, is getting 24V
Cold advance solenoid clicks is good
cold advance switch is good
I can blow into the return lines with a bit of pressure from my mouth and hear it in the tank.
Batteries are brand spanking new. Both were at 12.75 when I just threw them in.

I'm completely stumped. Why would it start immediately with ether and run fine all day, but I don't get fuel at the injectors when cranking it over? If it's a prime issue and I have fuel to the pump, how long should it take to get fuel to the injectors? I've cranked this thing for about 5 minutes, in 30 second intervals, 15 seconds in between and nothing. I get normal looking diesel smoke out the exhaust like it's burning fuel, but won't kick off. I do have a small drip into the valley between the heads. Haven't determined where exactly it's leaking from.


Is the injector pump just a standard commercial pump?

 

[infidel got me]

Its been a while back, but I seem to remember that we had a civy pickup that had kind of the same problem. I don't remember the exact details - I didn't work on this one- buy I do remember that the oil pressure switch was bad and had something to do with it. The switch was replaced and the truck ran fine. Don't know if this is related, but just throwing it out there. Good luck on repair and let us know what you find.

 

[Retiredwarhorses]

Its been a while back, but I seem to remember that we had a civy pickup that had kind of the same problem. I don't remember the exact details - I didn't work on this one- buy I do remember that the oil pressure switch was bad and had something to do with it. The switch was replaced and the truck ran fine. Don't know if this is related, but just throwing it out there. Good luck on repair and let us know what you find.

thats a civilian motor thing....if the OPS failed, it killed the electric lift pump. That won't be the case here as it is all mechanical.
i would replace IJ pump.....your pump is a 24v pump. I luckily have a standadyne shop not far from my shop, so I just give them the old pump and they give me a rebuilt pump.
but I find NOS pumps on sleeze bay for cheaper. For the 6.2 between 85-89 was a 4523 or 4524.
from 1990 and above it was a 4879, but I have used 4879's on trucks from 85-89.
standadyne said the pressure were the same and the only diff was a governor of some sort...anyway, hopefully your motor won't be toast from the starting fluid by the time you get it replaced, your well aware that it's a flat out NO GO on ether for this motor.
Just an FYI....cold advance switches will not prevent these trucks from starting, the fuel solenoid will of course. Also, just because you hear your solenoid clicking, does not mean they are working.
no fuel on cranking is a pump issue....seen it, been there, done that. Assuming you have a good fuel pump and no obstruction in the fuel lines or fuel filter as well.

 

[1 Patriot-of-many]

thats a civilian motor thing....if the OPS failed, it killed the electric lift pump. That won't be the case here as it is all mechanical.
i would replace IJ pump.....your pump is a 24v pump. I luckily have a standadyne shop not far from my shop, so I just give them the old pump and they give me a rebuilt pump.
but I find NOS pumps on sleeze bay for cheaper. For the 6.2 between 85-89 was a 4523 or 4524.
from 1990 and above it was a 4879, but I have used 4879's on trucks from 85-89.
standadyne said the pressure were the same and the only diff was a governor of some sort...anyway, hopefully your motor won't be toast from the starting fluid by the time you get it replaced, your well aware that it's a flat out NO GO on ether for this motor.
Just an FYI....cold advance switches will not prevent these trucks from starting, the fuel solenoid will of course. Also, just because you hear your solenoid clicking, does not mean they are working.
no fuel on cranking is a pump issue....seen it, been there, done that. Assuming you have a good fuel pump and no obstruction in the fuel lines or fuel filter as well.

I'm leaning that way. Thanks for the info. Just seems weird once started it will run great all day, and have no problems starting again. Yep I'm getting plenty of flow past the filter.

 

[Retiredwarhorses]

Yeah...that's weird. Here is something a lot of folks don't know. If you look in the newer TM's, you will see a check valve at the fuel filter inlet, part number 12342953-2. I also have a check valve on my fuel tank lines, both the fuel feed and the drain back line. These were done at the factory...this is "IMO" to prevent some sort of drain back, or possibly from loosing prime...I can't find at the moment the 2 at the fuel tank, just the one at the filter inlet, but as you can from the -2 part number...there are others like it but spec'd out different.

 

[Retiredwarhorses]

Ok, I was right....I just varified, 12342953-1 fuel return "at fuel tank"
12342953-2 fuel pump "at fuel filter inlet"
12342953-3 fuel supply. "At fuel tank"

the 2 at the fuel tank are inline with the hard lines from the tank and transition to the
frame rail hard lines...

 

[86humv]

On a motor from the past.....it leaked in the valley under the pump....was the plunger o-ring.
I have lots a new -3 valves available, and maybe a new 4879 pump.

 

[1 Patriot-of-many]

On a motor from the past.....it leaked in the valley under the pump....was the plunger o-ring.
I have lots a new -3 valves available, and maybe a new 4879 pump.

Is that where the throttle linkage rotates the shaft? That's where I just pinpointed my leak, and it's worse than it was, steady dripping once fuel gets to it..Took a couple cycles of 20 seconds cranking, 15 off before it started dripping... Still can't get it started. It's gotta be losing prime there. Is that a pretty simple fix? Do I have to take the FI pump off to fix that leak? God I hate it if I have to pull the pump off, I can't even see how you can get to the line connectors without taking the intake manifold off.

 

[Retiredwarhorses]

Is that where the throttle linkage rotates the shaft? That's where I just pinpointed my leak, and it's worse than it was, steady dripping once fuel gets to it..Took a couple cycles of 20 seconds cranking, 15 off before it started dripping... Still can't get it started. It's gotta be losing prime there. Is that a pretty simple fix? Do I have to take the FI pump off to fix that leak? God I hate it if I have to pull the pump off, I can't even see how you can get to the line connectors without taking the intake manifold off.

pump has to come out and be replaced...I have had my fair share of leaky pumps, and yes, if you can see fuel, that means air is getting in.

 

[1 Patriot-of-many]

Going to the shop most likely. I don't think I want to tackle the project. Still debating. Thanks Retiredwarhorses for the input. How long is the job of following the Tm's to pull the pump out and replace it?

 

[Retiredwarhorses]

Going to the shop most likely. I don't think I want to tackle the project. Still debating. Thanks Retiredwarhorses for the input. How long is the job of following the Tm's to pull the pump out and replace it?

its an 8hr job...the intake manifold has to come off, so you need new intake gaskets, new injector pump gasket.
the IJ lines come off as well. Remove the oil fill tube to access the 3 bolts that hold the pump to the timing gear.
carefull not to loose the bolts into the engine, rotate the crank to gain access to each bolt.
most importantly, when reinstalling, make sure the stud is in the oval hole and NOT the round hole.
its not hard....just time consuming.

 

[1 Patriot-of-many]

This is undoubtedly what will happen should I decide to tackle it. carefull not to loose the bolts into the engine, Never fails, if a bolt or nut can be dropped in the worst place possible, I excel at it.

 

[dmetalmiki]

Be brave, and be careful, you can do it just take your time. Have a large magnet and something to prevent the items falling into the works. There must be a way. good luck.

 

[1 Patriot-of-many]

What are FV432's going for over there? Me and the wife are dying to own armor.

 

[1 Patriot-of-many]

Well, I've decided to have it transported over to a Stanadyne place near me, have them take a look see in the magical thinking, maybe they can fix it without pulling the pump..... well I can dream can't I? It's just so strange, It will start right up with ether and run fine, restart without it, but when cranking before I get it started with a whiff of ether, I get drops out of cracking open an injector line, this should be a good stream right?..... i don't want to chance it anymore with ether so it's gonna get fixed....

 

[Retiredwarhorses]

Not much fuel comes from a single IJ line, it does not gush out, the pressure is at the other end of the IJ nozzle.
the pumps normally have to come out to be tested, but at my standadyne shop, the price to test is the same as buying
a rebuilt pump, with the old pump being used as a core for the dealer. So I stockpile pumps for all the various motors and when I get a bad pump, I pull from the shelf...I keep the old for cores if I need to get one exchanged at the dealer.
there are mucho better deals on pumps on the internet then the Standayne dealer can give me though...

 

[1 Patriot-of-many]

Now I'm really stumped..... Its 52 degrees here about 10-20 higher than the last time I TRIED to start this truck without ether. It started up within 5-6 seconds of cranking. The pump is not leaking either now!!!!!!....... WTH? fixed itself? LOL....... Is it possible the oil is not the right thickness? Maybe it wasn't cranking fast enough without using ether? That's in the troubleshooting guide as a possibility? Being quite a bit warmer now, maybe it's cranking the 150RPM I think was specified and it wasn't when it was colder?

 

[1 Patriot-of-many]

Update, I sent the HMMWV to a stanadyne dealer in ST. Cloud, MN ZIP's diesel injection Service, they had to pull the pump( intake manifold and all that entails, they replaced the seals on the injector pump at reasonable cost, still wouldn't start, we went back to basics. Apparently I damaged the new glowplugs I put in using ether a few times when the pump was leaking and losing prime. Personal experience after repeated warnings, do not use ether EVER ( it was definitely used to start by GP or the military also.) So they replaced them with AC delcos and it starts right up. Of course the real test will be when it's cooler. They checked compression on one cylinder during the process and it was 440 PSI. Like brand new. Good to have her back after about a month.