fuel filter change tips to avoid airlock

[Corpse]

I've got an 83 so my engine has two oil filter style fuel filters. My plan is to change one at a time and run the motor between changes. Also I will pre fill the filters with diesel, but do I need to lubricate the seals with grease or oil? Or is that unnesseccary?

Thanks for the help

[DmaxMaverick]

It's more simple than that. Unplug the IGN connector at the IP (usually the pink wire, powers the ESS with key on). Change your filters. Crank to bleed the filter(s) as necessary, primary first. (no way around that, unless you have an electric pump). Reconnect the IGN connector. Crank to start. It should start immediately and may stumble a bit after a minute at idle, but shouldn't require extensive cranking to restart and finish the bleeding.

You can eliminate almost all the excessive cranking. When changing at home, I use a fuel cap with a tire valve stem in it and apply minimal air pressure to the tank, about 2-3 PSI. The lift pump isn't required to lift fuel to the filters this way. It's also excellent for finding leaks and checking the new filter install.

The filter seals should be lubed with oil/grease. If none available (emergency/roadside), they should at least be wet with fuel. You should always be able to find some oil. Get some off the dipstick if necessary.

The greatest problem with changing filters on mechanical systems is, most folks try to bleed the system through the injectors. Lots of dead starters and batteries from that method. Disconnecting the IGN connector while bleeding minimizes the air being pushed through the IP and injectors.

[Corpse]

It's more simple than that. Unplug the IGN connector at the IP (usually the pink wire, powers the ESS with key on). Change your filters. Crank to bleed the filter(s) as necessary, primary first. (no way around that, unless you have an electric pump). Reconnect the IGN connector. Crank to start. It should start immediately and may stumble a bit after a minute at idle, but shouldn't require extensive cranking to restart and finish the bleeding.


ok so built that fuel cap you mentioned, super easy to do (advice to anyone else -buy a long stem valve, disassemble the cap and just drill a hole in the top + reassemble... took 10min and $15)

IGN - ignition?
IP - Injection Pump?
ESS - ???

1) unplug the pink wire at the injection pump
2) replace both filters filled with fuel and seals lubed
3) pressurize tank
4) open the valve at the top of the firewall filter to allow air to escape, then when fuel flows out, close valve
5) reconnect the pink wire at the Injection pump
6) crank/start motor... run for a few min till motor smooths out


correct?

thanks for the help!

[DmaxMaverick]

ok so built that fuel cap you mentioned, super easy to do (advice to anyone else -buy a long stem valve, disassemble the cap and just drill a hole in the top + reassemble... took 10min and $15)

IGN - ignition?
IP - Injection Pump?
ESS - ???

1) unplug the pink wire at the injection pump
2) replace both filters filled with fuel and seals lubed
3) pressurize tank
4) open the valve at the top of the firewall filter to allow air to escape, then when fuel flows out, close valve
5) reconnect the pink wire at the Injection pump
6) crank/start motor... run for a few min till motor smooths out


correct?

thanks for the help!

ESS = Engine Stop Solenoid. The fuel shutoff solenoid on the IP. Powered by the pink wire, to open fuel flow.

Correct, otherwise. I don't fill the filters, as that leaves a chance of your fill fuel to contaminate the clean side of the filter. This allows unfiltered fuel to get pushed to the IP. It takes a little more bleeding, but allowing the system to push fuel through the new filters eliminates this as much as we can. It isn't much more effort, if any, to do this if you use the pressurized tank method. Dirty fuel = shortened fuel system life. Every little bit helps.