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1994 Chevy Blazer 6.5L Turbo Diesel - No Fuel At Injectors

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1994 Chevy Blazer 6.5 Turbo Diesel, has no fuel to injectors.

The vehicle sat up for a while and I took various steps to clean, replace, and inspect parameters, but still no fuel to injectors.

1. I cleaned the tank and filled with fresh diesel,
2. Inspected the Lifter Pump and it is operational with expected fuel pressure,
3. Replaced the Fuel Filter, Gasket, and Cap,
4. Bled the Fuel Filter until diesel came from top,
5. Made sure diesel was coming out of every other place it was supposed to,
6. Cracked the injectors loose, no fuel to injectors.

Every port on the Injector Pump that is supposed to have fuel is dispensing fuel, but the cracked injectors are dry. When the key is in the ON position, the solenoid on the IP makes a sound as if it is working. I tested the plug going into the top of the Injector Pump and every pin read a voltage between 3v - 37v. The Fuel Injector Control Module is externally mounted with a heat sink and not tested as I do not know how.

The vehicle also had a Valet System in it for an after-market security system. I removed the system as it failed awhile back (reason for it sitting for a while). I did not install this system, so I have no clue as to what wires it clipped into and why. The system was installed with Wire Tap Connectors, so after removing the Valet System, the original factory wires are still connected and whole.

When I put the key in, the dash lights come on, the Solenoid on the IJ Pump sets, almost all dash lights go out, glow plugs warm, I turn the key to start, and the engine turns over pretty good.

All gauges function and oil pressure rises.
 
Replace return fuel line with clear line. Its the 1/4” diameter by approximately 5” long line that comes out for the ip (injection pump) return line. It is in the front and makes an upside down “U” shape.
You should see fuel flowing through it.
if you don’t, unscrew the fuel shut off solenoid a little bit snd retry. If it starts like this, turning off the key won’t stop it, so use a pair of pliers to squeeze the 1/4 return line until it dies.

Where exactly and how exactly are you testing fuel pressure? Pictures or YouTube video link is a good thing.
 
If this is where the return fuel line connects, that you mentioned. I have done so earlier, but forgot to put it in post. It has fuel flowing out.

I assumed fuel pressure is good due to the fact I forgot to put the screw back on the fuel filter cap and fuel went everywhere with a lot of force.

It’s like it has good pressure and fuel comfortably makes it up into the IJ. The IJ allows fuel to come out of the line I mention in the picture, but not to injectors.
 

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Yes the circled port is the return line. Just keep the clear line on there.
Watching for bubbles and contamination. It doesn’t take too many bubbles to make the optic sensor not function.

The other fuel port is the inlet. I suggest getting this adapter, adding a permanent mounted pressure gauge in the dash so you can read while driving. Proper pressure is 8-14 psi. As long as it is over 1psi the engine should run, unless the injection pump wasn’t getting proper pressure and has worn out the head and rotor. The lower pressure wears it out faster. Going under 0 psi into vacuum causes cavitation and wrecks it quickly.


I missed an obvious question already- have you tried replacing the pmd?
Hopefully you have it remote mounted out of the engine bay. Some folks carry a spare pmd in the glove box, I suggest having two mounted on heat sinks, one in use the other ready to go with a dummy plug in it to keep the connection clean.
Then when a problem occurs just move the wire over.
 
I have not tried replacing the pmd. The pmd is external, but still mounted in the engine bay with a heat sink.

I was going to try to test it, but could not find a good way to do so. I will purchase a new pmd, to try to see if there is any improvement. If not, then might it just be the IJ Pump?

Fuel pressure is good, filter and everything replaced, everything bled, IJ return line has solid fluid. The only thing not happening is the IJ to Injectors. I read that the plug, going to the top of the IJ Pump, should read 24v on some pins. My reading show 37v when the key is in the on position. Other pins read 2v-3v
 
There is no way to test the pmd- GM and Stanandyne list it as “replace with known good”.
Being in the engine compartment is bad. Originally mounted on the ip, when engine is running cold fuel cools the aluminum housing and cools the pmd. Shut engine off and fuel flow stops, ambient engine heat get the ip hot and ruins the pmd. When moved off the ip but in the engine bay, moving air will cool the heat sink. Truck stops moving and the heat sink will now absorb the heat from the engine.

Leroydiesel.com sells a lifetime warranty pmd alone or as a kit with heat sink.
You could also have a bad extension cable to the pmd. If you are not 100% confident who made the extension cable- replace it with one from Leroy.
 
Ok I will try that tomorrow. When I turn the brass t screw, a tiny constant-stream of fuel comes out when the engine is turned over… should it be more or less?
 
Cracking the T valve can let you suck air unless the lift pump is running.

It's very important you get the lift pump relay upgrade on a 1995 and older. It'll save you grief immediately or sometime in the future.

Buy Leroys. Or make your own. If you make your own, make it plug and play like Leroy's. Don't cut and splice.

Somewhere, there's a list of what pins should have what voltages running to and from the PMD

I mount 2 PMDs in the snorkel holes in the bumper - using the license plate bracket bolts. Sometimes, I was able to just add a heat sink and a nut.

Sometimes I had to pop rivet a piece of aluminum angle or something to the heatsink to get both heatsinks and PMDs oriented as I like them - with the plug pointed towards the opening but slightly back.

I took to running 2 extension harnesses up to the intake. - it's much easier to swap there standing up than it is the crawl in the muck and swap a PMD extension down there.

At some point in time, I always run the return line to a container. - it sounds like you've already done this.

The vehicle won't run with a plugged return. I've had that twice.

Where are you located? Maybe somebody is close and could let you try a spare PMD while you're waiting on a new one.
 
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I am located in Halls, Tennessee 38040.

I have tried almost everything mentioned and I think it will boil down to the PMD or the IJ Pump.

I didn’t think about a plugged return line. I will make sure it it returns fuel.

When I get it running, I am probably going to get spare CMD as mentioned, along with all the other modifications mentioned. Sounds like it makes life a lot easier.
 
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