starting after replacing glow plugs, injectors, etc.

[Neal Evans]

Good evening,

First, thank you all for advice on another thread regarding recommended glow plugs (Motorcraft all the way).

So, I've finish replacing the glow plugs (no breaks!), fuel injectors, and return lines. I also had to disconnect some of the steel fuel lines to check if they were still in good shape. Presumably, there's air in the system now. Is there a recommended procedure to crank the truck after doing all that? A friend recommended I bleed off the air by loosening the FIs. Is this a good idea and if so is there a recommended order to do so?

Basically, I don't want to risk burning out the starter by turning it over for 3-5 mins to clear the air.

Thank you for your advice!

-Neal

 

[gandalf]

Crank the starter no more than ~20 seconds at any one time. Let it rest for a couple minutes after that. So, crank ~20 seconds, rest the starter a couple minutes, allowing the starter to cool. Our engines run a 20:1 compression ratio. The starter works hard turning the engine over, fighting that 20:1 ratio. If you crank too much without a cool down period you WILL burn out the starter. That's not a pleasant experience.

 

[Selahdoor]

Crack the lines at all the injectors, before you turn it over.

Then crank only 20 seconds or so, and let it rest a few minutes.

Keep doing this, until you see fuel dripping from the lines at the injectors. As each injector shows fuel tighten it up. Leave the rest loose.

Crank again. Do this until all the injectors have shown fuel, and have been tightened.

That should bleed the air from the system.

Then let the GPs run, tap the go pedal to the floor and let it back up. And then start 'er up.

 

[chillman88]

Also, as you're cranking, keep the throttle fully depressed. I don't know for certain if it helps, but it certainly seemed to any time I needed to bleed air from mine.

 

[Neal Evans]

I got it running by bleeding at the schraeder valve until it was squirting fuel. Smoking like the devil, but running well. Thanks!

 

[Tod Rockstead]

Easy prime for fuel system

Recently I had to replace the lift pump, O ring's on the injectors & install a few segments of clear hose to help diagnose air intrusion on my 86 F250. So all fuel had drained from the tank forward. So i went out to a local auto parts and purchased a Fuel Hose with a inline pump ball, like you would find on a motor boat and attached it to the steel fuel line from tank to the input on lift pump. It is also helpful to install a segment of clear 1/4 " Fuel hose at the fuel filter to the fuel return cap on the front injector. With Ignition in the Run position prime fuel lines by squeezing the priming ball until you see fuel flowing into the return lines with little or no bubbles. then crank engine to start. Once engine spins up and all air is purged from fuel lines use vice grips to seal segment of clear hose connected to the metal line from the tank & detach the priming ball and remaining hose from from fuel pump, recreate fuel loop and reattach hose, tighten clams on hose input of lift pump & remove vice grips.



86 Ford F250 6.9 IDI AUTO 4x4

 

[Big Bart]

You should also now check your timing. New injectors can change your trucks timing. Basically injectors brands and older injectors have slightly different opening PSI's. So old tired injectors likely open early so they add more BTDC timing. Newer injectors will open later at a higher PSI, so a later BTDC or possibly ATDC timing if your truck was timed with aging injectors. Just a good best practice!

All the best!

 

[Neal Evans]

It’s running pretty great, not even much smoke, so timing is hopefully pretty close to optimal.

 

[IDIBRONCO]

Glad to hear that.