John Mule

I didn't really "tamper" with it. I just replaced the o-ring at the action pin because fuel was leaking into the AFC housing. I managed to do it without removing the whole pump; I just took off the top. I marked everything as I went along, so it should be reassembled the same as I found it. The only thing I changed was turning the eccentric pin a few degrees, because it had scoring where the other pin was riding on it. After I put everything back together, the truck's not sounding just right.
I can't describe the sound, other than it just doesn't sound even across all the pistons. Almost like air, but I bled from the bleed screw and at each injector, several times. There's no white smoke like air in the fuel. There's also an occasional sound like gears not meshing when I start up and when I'd bleed an injector, which goes away if I give a little throttle. That's the noise that's really got me worried.
I understand it's impossible to diagnose sounds without hearing them, but I'm sure hoping somebody might have some experience with a similar problem!

wannadiesel

It sounds like you've still got air in it. How long have you run it?

Alec

John,

I apologize if this is obviously not the case, but it is the only thing that I can think of that would explain your problem: Is it possible that when you put the pump back together, the idle got set lower than it had been before, so that you are hearing different harmonics, and that is the only change?

How did you get the ***** out that cover the ends of the AFC pivot? I ground the first one out with a dremel tool, and then drove out the other, but I'm looking for a better way!

John Mule

Thanks guys for trying!
Wannadiesel: I worked the truck pretty hard (over 200 miles and pulling a stock trailer) since I put the pump back in, because the new o-ring was tight and I thought maybe that action pin needed to loosen up ???

Alec: I did have to turn up the low idle when I was done, but the sound is there through all the RPM range. Will the low idle change the harmonics all through the range?
To get those ***** out I supported the AFC housing with wood blocks and rapped them out with a narrow punch. I drove them back in with some Loctite on them. Pretty crude, but the best I could come up with.

Shouldn't I have white smoke if there's air in the fuel? Is there a sticky with the proper bleeding procedure? I followed the factory service manual, but maybe I did it wrong....

wannadiesel

All the bolts holding the pump on are tight?

After 200 miles of work the air would be long gone. If you can get them started they'll usually clear themselves out in less than 10 minutes.

John Mule

I checked the bolts -- all tight. And old matchmarks from the prior owner show that the pump hasn't moved. But I did notice a new fuel stain under the lift pump...I'll put a new one in tomorrow. Could a bad lift pump cause the noises I was hearing?
Thanks for your help...I would really be stuck without the information on this site.

wannadiesel

If it's letting more air in all the time, yes.