Injection Pump Issue - Runaway or Idle Miss

Hard to see... is it scored or something?

How did the advance mechanism feel? It was binding or not rotating smoothly?

-Todd

ToddA1 said:

Hard to see... is it scored or something?

How did the advance mechanism feel? It was binding or not rotating smoothly?

-Todd

Click to expand...

Oh yeah, the bore of it is wasted. Not sure if some trash got into the pump and machined the bore or if it is just because the pump has 280k miles on it. Either way, it'll need a new pump

Advance mechanism felt terrible on it. Wasn't rotating smoothly and would bind while rotating.

Bad news... from the pic, it looks normal to me. I just pulled the head from my project’s pump to check for rust/varnish and that one ring I see, is supposed to be there.

If you had the pump resting with pressure on the mainshaft, the roller cage and piston will not move smoothly.

Was this the pump that you swapped the 11mm internals into?

-Todd

ToddA1 said:

Bad news... from the pic, it looks normal to me. I just pulled the head from my project’s pump to check for rust/varnish and that one ring I see, is supposed to be there.

If you had the pump resting with pressure on the mainshaft, the roller cage and piston will not move smoothly.

Was this the pump that you swapped the 11mm internals into?

-Todd

Click to expand...

It is the same pump, yes. Swapped from the cam plate out to the delivery valves out of an 11mm ALH pump.

The bore on mine definitely has an issue. This picture is from an older IDI pump, but I see the bore is smooth where the roller cage goes. Mine has a very definite hard edge and then down into a valley as you run your finger into the bore.



Where as on mine, it's hard to see, but you can see a definite machined surface starting at about 12:30 in this picture all the way around to about 5:00.

Ah, now I think I’m seeing it.... it’s in front of the hole that the roller cage pin would be dropping into the advance piston.

-Todd

ToddA1 said:

Ah, now I think I’m seeing it.... it’s in front of the hole that the roller cage pin would be dropping into the advance piston.

-Todd

Click to expand...

Yep...

So update to this. I picked up the NOS Injection pump from the classifieds. Swapped the 11mm head/plunger/cam plate into it, and got it on the car. After bleeding the pump and injections, got it to start up. Haven't even checked the timing or IQ yet, and it runs awesome.

https://youtu.be/Rs-9yAtz_vI

Glad to hear!

-Todd

Just strange that the pump with the same wear a few months ago ran fine.

KLXD said:

Just strange that the pump with the same wear a few months ago ran fine.

Click to expand...

I 100% agree. Just a big coincidence, I guess. Everything has to break at some point. I guess it was just that pump's time.