AHHH... Whats Wrong With My Fuel Filter?!?

[nate_o23]

Ok heres whats going on, my 85 burb has been getting sluggish lately and the WIF light has been coming on a lot(especialy under load). I decided to go ahead and change the fuel filter(single, rectangle kind). When I tried to drain the filter nothing came out the bottom even with the plasic screw all the way off. When I took the filter off there was fuel in it. I put the new one on disconnected the IP wire (fat pink one right?) opened the top plastic air bleed screw and cranked it over. No fuel. I took the top screw all the off and cranked it. No fuel. Next I took a flashlight and looked down the air bleed hole and there is something blocking the hole. I dont know what it is but I poked it with a screwdriver and it is pretty hard. What is this?? Is it supposed to be there?? What gives??

[nate_o23]

Anybody???

[john8662]

Sorry for the delay.

I had to take the time to dig out my "parts" Model 80 fuel filter holder and take a closer look.

Anyways, I removed both of the plastic petcocks from the fuel filter holder.

The bottom petcock is for draining water out of the fuel filter. When looking at the holder you can see that the bottom nipple on the fuel filter holder that goes into the lower connection on the filter for draining water. This connection basically makes a 90* turn into the filter. So the only thing in that hole would be a small neoprene gasket, with a smaller hole in the middle that immediatly dead ends for the 90* turn.

The top petcock is for allowing air out of the fuel filter housing after a filter change, which you know. This connection when removing the petcock you'll see a reduction in the size of the hole, so if you're sticking a screw driver down in there it will stop. The hole where the fuel travels is only about 1/8". So if you're concerned that is is plugged, take a piece of wire (bailing wire etc.) and see if it's plugged.

If it's all free and unplugged, then it could be a failed fuel lift pump thats not getting fuel up to the fuel filter housing.

Good luck!

[nate_o23]

Thankyou very much for the info. When I look down the air bleed hole there is no opening at all so it must be plugged. I am glad you told me that the opening is only 1/8" because I would have tried to ream it out all the way.

[john8662]

At this point, I'd go ahead and pull the whole assembly off the firewall and do a real good clean job on it.

All thats involved is disconnecting three electrical connectors, two fuel lines, and the three mounting bolts up top.

With the holder removed, you can then take the fuel filter back off the holder and get to business. Get a can of brake parts cleaner or carb cleaner and use the straw and blow all the tubes out. You'll already by this time have the two petcocks removed from the assembly. Make sure that you still have a gasket in the lower water drain petcock though.

I'm sure that since your filter housing is plugged that this could explain for the poor performance and the WIF light being on, because it also comes on under restriction problems.

J

[nate_o23]

That is an excellent idea. I think I will tackle it on Friday, will let you know how it turns out. Thanks again.