Fuel injection high pressure pump question.

[Bruce B.]

Re: Fuel injection high pressure pump question.

John,
Well I checked the 4360 and here is what I found.
The Tee is a number 25. This is a 0.025" restrictor as described in a RP Field Service Bulletin dated 2-1-57 shown in Kens book on page 576. I checked the orifice with a 0.031" drill and it would not enter so it is probably really 0.025". I have to assume at some point in the life of the unit it was upgraded to this restrictor. This small restrictor should call for less fuel, isn't that correct?
But, the coasting shutoff valve is still on my unit so maybe that makes my previous statement incorrect. I'm not sure exactly how and when the coasting shutoff valve functions.
Last but not least are the nozzles. They are Q12 type.
After reading an old post of yours it seems they are correct for 4360 the 283 HP version. My 250 HP unit should have Q11 nozzles.
Could any of this info be responsible for my poor gas mileage.
But as I said the unit runs and starts great so this stuff is not a issue although a little more gas mileage would be good.
Bruce B

[John D.]

Re: Fuel injection high pressure pump question.

Bruce, Once in a while I hit it lucky on a wild guess. I think you might try replacing the .025 Branch T fitting with a later 57 style. Your fitting has a huge hole in it. I never saw one with a .025. Whew!!!
Try a .016 or even a .018 T fitting from a 4800 or so unit. What that will do is tame down your fuel meter a tad so it won't be using up so much expensive fuel.
Happy to hear you have '4520 nozzles in your '4360. Although the 4520 nozzles are still short and stubby they are a far site better than the originals.
So you still have the coasting shut off valve hooked up?
Since you are from Ohio did you know Frank Cichon? He spent 1/2 of his life trying to prefect 4360's. Frank was my pal for many years. He worked very hard and spent big bucks trying to make the coasting shut off valves work. Frank's gone now. Gail Parsons worked hard on the CSO too.
That whole idea was a flop you know. RP gave up on it after a few months and came out with a bulletin on how to eliminate it. The kit included another Branch T with a smaller restrictor fitting, a wild set up to block off the big hole in the end plate of the hi-pressure pump, etc.

Don't tell anyone but here is a super cheater for your 57 FI fans that are running a '4360 or '4520 unit that you just can't tame down. One that just runs too fat and your are stuck and don't want to spend major bucks to have it worked on.

Use a smaller restrictor fitting on the main diaphragm cover. You will have to make this yourself though. Put a restrictor in the T fitting that is about .014 to .016. This weakens the signal to the fuel meter making it use less gas.
Is this the kosher way to do this stunt. Nope. Gail Parsons wouldn't approve of this as told me so. But I will tell you it works like a miracle.

Story: One time a local fellow had a 4520 unit that we just couldn't fix. It always ran fat. Now this was a good 30 years ago and old JD was still in learning stages. (still am).
I remember reading about the cheater restrictor fitting so we made one up with solder and drilled a hole in the solder with micro drill bits.
I mean it worked like a charm. Well we didn't believe it so we took out the .014 fitting and put the .022 fitting back in (wrong fitting to start with) and the car ran rich.
Proper way to tame down a '4360 unit and a '4520 unit is to put a blead in the air meter like Gail did. My way is not correct but it works.

[Bruce B.]

Re: Fuel injection high pressure pump question.

John,
Thanks for all the info.
I will study it over the winter and decide what to do.
Have a Great Christmas and a Happy New Year.
Bruce B