mfi reassembly questions

[jkeyzer]

For the MFI gurus:

On the throttle bodies:
1. Should I grease the return springs or bushings after having solvent cleaned the throttle bodies? Any special concerns elsewhere?

I removed and cleaned all the injectors (ultrasonic), so they are all nice and shiny inside and out, this leads me to:
2. Do the fuel lines and injectors need to be primed somehow before trying to crank the engine, or will they prime themselves? Should I be expecting to crank for a long time to work the air out of the lines?

Thanks!

PS. If anyone has any of those rubber fuel line retainers for the TBs lying around, let me know. See pic below.

[jkeyzer]

[Rustbucket]

Wow!
That's clean.

Sorry I don't have any advice.

Future MFI guru.

[Rot 911]

Jeff, on my 72E I did the same thing when I had the engine out. On the throttle return springs I sprayed a dry lube on them. On the throttle rod cups I used Swepco grease, same as I use on wheel bearings. I don't know any easy way to prime the pump and lines, I just pulled the spark plugs and let the engine spin for about 10 seconds, put the plugs back in and it still took about 5 seconds of turning the engine over before it fired up. One more thing, now is the time to set your throttle plates prior to reinstallation. I believe the correct settings are to adjust the throttle screw until the throttle plate just closes and then open each one back up 3/4 turn.

[Early_S_Man]

Jeff,

Those throttle assemblies look brand new! You should be proud of them!

I have used Permatex Anti-Soeze Compound on the cups of the ball-and-socket links for years ... it does not 'run' out, and even when dry, the lead-copper residue is still an effective lubricant and takes up any gaps due to wear.

You can make new guide blocks from a used, scrap motorcycle tire ... preferably one of the rear semi-slick designs, by cutting into the appropriate sized block with a hacksaw.

As far as priming the injectors does, it won't be necessary. When you have the system ready to attempt restarting, let the fuel pump recirculate fuel for five minutes before you crank, then try the restart. It shouldn't take more than a couple of 20-30 second crankings to fill the lines. Good luck!

[Oldporsche]

I know that the pieces inside your injector nozzel are mild steel. You might store them in an air tight container with some sort of moisture absorbent. I would just put them in a can of oil until they were going to be used. You might check the spray pattern on them. Use kerosene or paint thinner from a pressureized container. You could put a pressure guage in line with a Tee fitting to check the opening and closing pressures.

For MFI they are higher than CIS.

You can use a unisyn to check the air passing through each stack at idle. There are a lot of adjustments that are possible with this system.

One of the tricks I learned was to disconnect the cross linkage between the banks. You can check the reaction of the motor seperately on each bank. This can help you trouble shoot your motor. You can find a misfiring cylinder, etc. This will also help you in setting up the injection, especially at idle. When you are done you can adjust one link to make the cross bar connection "neutral" and have the same amount of movement in all six butterflies.

As you know, when this system is sorted out, it can't be beat.

Good luck,
David Duffield

[jkeyzer]

Kurt -

I have completed all the adjustments to get to a baseline but expect to have to do some tweaking once I get the engine started again. Thanks for the tips on getting things back together. I was expecting a lot more cranking to get the injectors running on fuel again. That's good to know it should only take a few seconds if everything is working.

Warren -

Thanks for the tip. As you can see those rubber pieces are pretty much shot. Everything else looks good though and I have high hopes that the stacks with synchronize up. I didn't rebuild these other than just cleaning them out very thoroughly. I should put a "before" pic up here but it's ugly.

David -

I didn't realize corrosion could be a problem. I'll be putting the injectors back in within a day or so though so they haven't been on the bench for very long.

Thanks for all the replies so far, as usual they are very helpful.