300 TDi Fuel Injection Pump woes

[Craig Almaguer]

Hello all,

My defender 110 300 TDI injection pump was leaking between the main body and the distribution head. After some research I decided to replace the O-ring in situ. A little bit of a challenge, but I got the old O-ring out and the new one in ….rolling the o ring over the bolts one at a time and into place.

Now the fun began. I am unable to start the vehicle. I have bled everything I can think of but I’m not getting fuel at the injection lines

Solenoid is getting power and clicking, so I assume it is working. Lift pump is less than three years and sending fuel to the filter….from filter to IP intake, there’s fuel, fuel at rear return bango bolt also.

Again, it just seems like I’m not getting pressure within the injection pump to push fuel to the distributor head and then up to the injectors. The pump was working fine with the exception of the leaky O-ring. Now I’m stumped I don’t really want to spend $1500 on a new injection pump. Your input is greatly appreciated.

Craig

 

[Z.G]

One thing I typically suggest is taking the line from the filter to the IP off at the filter and just submerging it in a cup of diesel and trying to start it like that. Typically rules out anything fuel supply related.
Then there's obviously timing, but shouldnt be an issue if you never removed the pump and it ran fine before the leak
Then there's the stop solenoid. In theory if it's clicking it should be working, but might be worth removing it and testing the functionality.

 

[Craig Almaguer]

Zack? Rover North, Zack? Thanks! I’m kinda thinking the injection pump is “toast” but I just don’t know ? Hard to believe I drove Marlin 5 hours two days ago with no issues (other than the known o ring leak), and now fuel line challenges. Solenoid is a bitch to remove in situ as they say. And yes, never removed the pump itself. Replacing the boring in place, I separated the parts only by about 3/16” + then put back…tightened back the bolts. Some movement of the parts, but very little. (???)

I feel there’s pressure at the intake bango and the return bango….just not pushing to the distribution head/injectors.

In this process, has the pump body become toast? Hard to believe(?)

 

[michael67]

Have you loosened all the injector lines a bit on the injector side as you crank the engine? I've had to do this.

 

[Z.G]

Zack? Rover North, Zack? Thanks! I’m kinda thinking the injection pump is “toast” but I just don’t know ? Hard to believe I drove Marlin 5 hours two days ago with no issues (other than the known o ring leak), and now fuel line challenges. Solenoid is a bitch to remove in situ as they say. And yes, never removed the pump itself. Replacing the boring in place, I separated the parts only by about 3/16” + then put back…tightened back the bolts. Some movement of the parts, but very little. (???)

I feel there’s pressure at the intake bango and the return bango….just not pushing to the distribution head/injectors.

In this process, has the pump body become toast? Hard to believe(?)

The very same sir. But yes, I'd be surprised if the IP is actually toast at the same time you replaced a seal on it, seems too coincidental.

Have you loosened all the injector lines a bit on the injector side as you crank the engine? I've had to do this.

I assumed that's how he determined he was not getting fuel at the injectors

 

[Craig Almaguer]

Well technically not ALL the lines….two at the distributor head for one go….and then all four once at the top rail/manifold. Again, it appears nothing is getting pushed from the main body past the o ring area at the distributor head. Even if I botched the o ring install, you’d think I’d have fuel spilling everywhere from that joint, wouldn’t you think?

 

[michael67]

Just for clarification, when you say you "feel there’s pressure at the intake banjo", did you bleed at the intake banjo?

 

[Craig Almaguer]

I vacuum pumped from the tank to the lift pump. From lift pump to filter, bled. From filter to intake at IP, bled. From intake to return bango, bled. Pressure at all these locations. Just nothing coming out at distribution head/injections and certainly not at the top (injection lines). All cracked. The body of the injection pump is jacked somehow. New injection pump ordered. Sigh.

 

[Z.G]

I vacuum pumped from the tank to the lift pump. From lift pump to filter, bled. From filter to intake at IP, bled. From intake to return bango, bled. Pressure at all these locations. Just nothing coming out at distribution head/injections and certainly not at the top (injection lines). All cracked. The body of the injection pump is jacked somehow. New injection pump ordered. Sigh.

Im still curious about your cutoff solenoid, but I can check that when you send your core back for credit

 

[Craig Almaguer]

What in particular about the solenoid are you curious about? I have “checked “it and hear clicking with the ignition key on. Could something else be wrong with it? I find it hard to believe that it worked yesterday and now that I’ve put the O-ring on it doesn’t work.

 

[Z.G]

It's likely fine, but it's the culprit 4/5 times. Something else could definitely be wrong with it, but usually a failing pump still sends fuel

 

[michael67]

I've had an after market version of that solenoid go out on me within a few months. I replaced it with a genuine VW part about 10 years back - no problem so far.

 

[expanse]

my two guesses of the day. first guess; the control sleeve has fallen off the governor lever. second guess; the plunger shaft is not seated on the drive peg.