Bleeding fuel injection lines-108 M130

[mbgingerbread]

I am running on the cold start valve-not much else.......
Is there a recommended procedure for ensuring that I have good fuel pressure at the injectors?

[Todd Miller]

If this has a mechanical injection pump and steel lines to each injector, you crack the line fittings at each injector, and then crank 'er over in 10-15sec bursts until you have fuel coming from the loose fittings. Then snug up the fittings and it should fire up. Typically, holding your foot to the floor and making the pump go to full enrichment will help in all of this.

[mbgingerbread]

Thanks, Todd
I will be wrenching this weekend eliminating run problem.
Reading one of the Pertronix posts I had to change to a 3.0 ohm coil in order to follow set-up instructions-the supplier sent me a 1.5 ohm by mistake.
I haven't operated this vehicle much in between doing this and that so I may have bled the injector lines insufficiently. In the meantime I have been replacing parts but with a 37 yr old car it's worth doing so when your long term goal is a good as new vehicle. But the best part is really getting to know your car................

[Todd Miller]

My suggestion would be to get it running correctly with the original ignition set up. The Pertronix is not going to "cure" or "fix" any running or driveability issues, and right now, while you're just trying to get the car running, it could be adding an extra (uneeded) variable into the mix.

[mercmad6.3]

Air in the lines shouldn't be an issue with MFI unless you have a fuel flow or supply problem. The injection pump needs a supply pressure of 14 PSI but the pump builds the pressure up to the injectors. Try changing your fuel filter.

[mbgingerbread]

With the help of my 'Senior Manager' I bled the injector lines-fuel at each injector. I tightened the injectors 1-6 to be sure that I didn't have any leaks beforehand....Fired up and voila!-ran for 20 minutes with a short trip around the neighborhood. When I pulled into the garage voila-instant stop.
So, I had noticed that the small section of rubber hose between the fuel filter discharge line and the suction side of the injection pump and the cold start feed pipe was partially collapsed. Decided to change fuel filter-disgusting crud in the bottom of the filter housing.
So, will change and re-post with the results.
Thanks.......

[Todd Miller]

Let that fuel hose and filter be a BIG warning to you about the condition of your fuel hoses (back at the fuel tank), the screen in the fuel tank, and the screen at the entry port on the electric fuel pump back below the fuel tank. Same with any rubber fuel lines in the engine compartment.

Regarding the bleeding the injectors on mechanical injection; It's needed on both diesels and gassers, if the system has been opened. It's the pressure pulse from the mechanical injection pump that opens the mechanical injectors. If there's air between the injectors and the injection pump, the pump isn't going to be able to open the injectors and purge the air in the lines (very fast.......if at all).

[mbgingerbread]

Hi.
Replaced fuel filter and small rubber connector. Good results. Set timing at 3ATDC with vacuum connected and idle at 550 using the screw adjustment at the intake.
Good run for over 45 minutes. Can see the need to replace rubber and steel lines as well as pull the gas tank for a proper cleaning. Had replaced the fuel pump and tank screen earlier so the dump which I got in the old filter may have been related to that work. But as I mentioned before will basically re-do fuel system connections as time permits.
Is it OK to use copper and or stainless for the replacement fuel lines?

[Todd Miller]

Isn't idle spec up in the 750-800rpm range? 550 is pretty low.

You might be able to just blow through your existing lines with compressed air and continue to use them. Or roto-rooter them out a thin piece of steel cable with a slightly freyed end, and stick the cable into your drill. Then flush with carb cleaner and finally compressed air.

[mak]

Most helpful advise from Todd to follow ,copper pipes are not recommended for some reason.
mak

[mbgingerbread]

Thanks,
I like the idea of the frayed cable to clean the lines-very effective in combination with the carb cleaner.
Increased the idle speed to reflect the correct reading as you suggested.
I also used a glass bead blaster to clean the warm running device which should help the initial idle roughness on cold start-hopefully.

[Todd Miller]

Keep picking away at it. Great way to learn and you'll dial it in more and more each time until you have it running like a watch. These cars are all about finesse.

I'm guessing copper fuel lines would have a chemical reaction with the fuel and create that weird green oxidation sludge.