fuel pump dia. & pin

[cwienenga]

after reading all the helpful info from you guys lately, I removed my dia. and checked for the pin movement. couldn't see it at all, I guess it is pulled back and stuck back inside. I talked to local fuel shop and they showed me how it is installed in top housing which must come off to get it out. anyone tried this on engine before. sounds a little tricky but not impossible.



thanks

cliff

 

[BushWakr - RIP]

It is a heck of a job when it's on the truck... or so I'm told.

I also understand that the main culprit in this is the O-ring at the other end of the pin. I guess it gets all gummed up or brittle or something.

I've wondered if something like 'seal restore' would help. If it can be "refreshed" and softened up/lubricated then maybe the pin will once again move freely. ????



Also the pin will not be showing when you first remove the AFC diaphram. When you pull the diaphram it forces the pin back into it's little hole. You normally need to cycle the throttle open and it will then pop out,,, that is if it's working properly.



bob.

 

[cwienenga]

fuel dia & pin

thanks for reply

I tried cycling throttle numerous times-no diff. there is a groove on the tappered cylinder where it has worn in the past but nothing now. this would make sense, I only could get 10-11 lbs boost on hill full throttle ( not towing but dead lug),and never any smoke.



cliff

 

[Scot]

Re: fuel dia & pin

Originally posted by cwienenga

thanks for reply

I tried cycling throttle numerous times-no diff. there is a groove on the tappered cylinder where it has worn in the past but nothing now. this would make sense, I only could get 10-11 lbs boost on hill full throttle ( not towing but dead lug),and never any smoke.



cliff

No smoke with those numbers are about right for a stock engine. That is about all mine would do. POD's dude!

 

[BushWakr - RIP]

Yes, on a stock truck, particularly an auto, the average boost would run around 11-14 psi, no matter what the doofus manual says...

Keep in mind I said 'stock', as in no fuel adjustment, no timing adjustments, no airfilter/exhaust mods,,,, no nothing.

All you need to do is increase fueling and you'll see more boost. (which means it's not 'stock' anymore)

Since you have 'witness marks' on the cone then the pin was working at some point. Like I mentioned above, perhaps you can get hold of some seal refresher (my term) kinda like the additive used in ATF or PS fluid, to help soften up the O-ring. That's assuming the O-ring is the direct problem.

Now that I think about this, I'm gonna go look at the parts diagram for our pump and see what jumps out at me... . hmmmm. .





Bob.

 

[Lil' Dog]

Add a film of lithium (white) grease to the fuel diaphram where the pin should ride and re-install it. Go for a rip and pull it to see if the pin has contacted the eccentric cone. If not then you are into some repairs.



Also, if the diaphram was easy to remove, then the pin wasn't contacting the cone. I usually have to pop out the diaphram a couple times to get the little pin to receed.



J-eh

 

[BushWakr - RIP]

Lil' Dog's idea is a good one and I've used it a number of times myself. The grease basically gives you a chance to see if the pin has come out, and contacted the cone and just as importantly, were it contacts too...

I looked at my schematic and it does not show that part of the pump disassembled, all the rest, but not the AFC housing and immediate components... figures

I'll have to get the rest of the pics from the shop. .



bob

 

[cwienenga]

AFRC

THANKS FOR THE INPUT GUYS. today I removed that front plug and worked the pin back and forth with lubrication till it felt smooth. reassembled and test drove. Throttle response was much better although the o-drive wasn't working right. was checking the manual and I think I attached the rear return spring to the pump and it looks like it attaches to the eye of the trans cable, will change it and try again tomorrow. hopefully the o-drive will be back to normal but the improvement will remain,the low end response was night and day.



cliff

 

[BushWakr - RIP]

Oo.



I luv it when a plan comes together. .