Fuel Pump Install - Cam Position?

[PossumF250]

I'm in the middle of replacing the mechanical fuel pump on my 6.9 IDI, and I'd like to know if/why the cam position matters when installing the new pump.

I'm thinking that if I put the new pump in exactly as the old pump was, it should be fine and cam position should be irrelevant as long as the arm/lever is below the cam lobe. However, the instructions that came with the pump and the DieselHub article on IDI fuel pump replacement both state that the tall side of the cam lobe that drives the pump should point upward when the new pump is installed. Mine appears to be pointing downward, and I'd rather not deal with the hassle of getting it turned 180 degrees if I don't need to, but certainly will if it is necessary.

Does the cam position really matter? If it does, why, since the lobe will rotate through all positions with the engine running?

 

[Cubey]

Yes, it matters.

Just disconnect your fuel cutoff valve wire and bump the starter with the key so it will crank but won't start. That's what I did for gaining access to my C6 torque converter drain bolt.

 

[chillman88]

You can do it without, but it's a real pain. You'll have to fight the internal spring while trying to get the bolts started.

You might very well end up spending more time trying to install it that you would getting it lined up.

That said... I've done it before without lining up the cam lobe. Like I said, not fun.

Pull your alternator and vacuum pump first, makes it much easier to get in there. Some people like installing it from underneath, I don't particularly care for that method myself.

 

[Cubey]

Some people like installing it from underneath, I don't particularly care for that method myself.

I pulled it off from the bottom on my RV and no it's not fun. Since I was going epump, it was ok since putting in the block off plate was easy enough.

 

[PossumF250]

Yes, it matters.

Just disconnect your fuel cutoff valve wire and bump the starter with the key so it will crank but won't start. That's what I did for gaining access to my C6 torque converter drain bolt.

Okay, so I should be able to just pull the fuel cutoff valve wire on the injection pump and give it a quick crank with the key, check the cam position, and repeat as necessary till it's in the correct position?

You can do it without, but it's a real pain. You'll have to fight the internal spring while trying to get the bolts started.

You might very well end up spending more time trying to install it that you would getting it lined up.

That said... I've done it before without lining up the cam lobe. Like I said, not fun.

Pull your alternator and vacuum pump first, makes it much easier to get in there. Some people like installing it from underneath, I don't particularly care for that method myself.

Good to know! I won't be trying to install without lining up the cam lobe then.

I've pulled out the inner fender to make access easier (supposedly the job is easier that way, but I'm skeptical after the effort it took), so I'll have to reinstall the passenger side battery and the bracket that supports it to turn it over with the starter, but that's no big deal.

 

[chillman88]

I've pulled out the inner fender to make access easier (supposedly the job is easier that way, but I'm skeptical after the effort it took),

Yeah I'm up in the rust belt. Up here removing the inner fender requires drilling out all those screws that are always rusted in place and that's not going to happen

 

[Cubey]

Okay, so I should be able to just pull the fuel cutoff valve wire on the injection pump and give it a quick crank with the key, check the cam position, and repeat as necessary till it's in the correct position?

Yep. That's what I did for the TC drain. It took many times but i got it there.

 

[PossumF250]

Yeah I'm up in the rust belt. Up here removing the inner fender requires drilling out all those screws that are always rusted in place and that's not going to happen

Haha! Mine wasn't quite that bad, but it wasn't pretty either. I had to remove the running board too, and the bolts were so frozen in place and corroded they all snapped as I tried to remove them.

 

[PossumF250]

Yep. That's what I did for the TC drain. It took many times but i got it there.

Okay, well that's what I'll do. I've already put a good number of hours in this project, so even if it takes quite a few tries, I guess it shouldn't take long relatively speaking.

 

[IDIBRONCO]

so I'll have to reinstall the passenger side battery and the bracket that supports it to turn it over with the starter, but that's no big deal.

You wouldn't have to do that. It's just using the starter to turn the engine over. If you have a manual control on your glow plugs or disable the controller so they won't kick on, you won't use very much power from your driver's side battery to turn the engine over a little bit.

 

[Clb]

R
E
A
L
L
Y?
Ok stuff it in.
Report back!

 

[SevenThree91F250]

maybe you ought to do this I just found this video

xc_hide_links_from_guests_guests_error_hide_media

 

[PossumF250]

You wouldn't have to do that. It's just using the starter to turn the engine over. If you have a manual control on your glow plugs or disable the controller so they won't kick on, you won't use very much power from your driver's side battery to turn the engine over a little bit.

Sure enough, I didn't! I didn't even mess with disabling the glow plugs and it cranked over on one battery with no problem. It took 3 tries (I think) to get the cam in the right position, and from there installing the new pump was easy. I started it up on the one battery and it ran well once it worked out the air. Now to put the inner fender back...

 

[IDIBRONCO]

That's even better. I'm glad that it worked out for you.