Do you need a injector pump on a6.9 or can you by pass
 

Ok so I bought a 84 f250 6.9 and was told it had air in the fuel lines so I replaced the injectors and went to bleed the system and found that the guy by passed the injector pump. I'm worried this will mess up the motor or just not run any help? Do want to mess up a good motor.

?? there is no way to bypass the Injection pump .. or are you refering to the Lift pump on the Passenger side of the block ??? :humm:

I would not recommend trying to bypass the injector pump.

:td:..LOL.. not a good way to get fuel into the injectors that way .. LOL..:nope:

Ya sorry it's the lift block that's been removed. I put two new batteries in it bleed the injectors and bleed air out of the fuel filter and it fired right up I bleed the injectors with it running and haven had a problem starting it all day but it's blowing a lot of blue smoke when it's idling and if I rev it up its spits and then catches and blows huge clouds of smoke. I was thinking it's because the injectors are out of time and the injector pump needs turned down but not sure.

Your injection pump would be out of time not your injectors, seems unlikely if it has not been out, if it has been out then look at that first.

The smoke issue, blue at idle untill you step on it, then it blow black? Or a lot of blue?

It blows blue, I'm not sure what to do but I know I'm not getting rid of it I love this truck

Ok so after talking to the guy I got the truck from here's what's been done. He by passed the lift block and the water separator rewired it and put the glow plugs on a push button and he put 5 inch straight pipes on it. Not sure if putting big exhuast on it with no mufflers has anything to do with anything but don't I need some back pressure so it runs smooth

blue smoke is an indication of oil being burned.

No, Back pressure is not a factor.

I would get the truck timed, putting new injectors in will alter it and you should have it rechecked.

i am not a crazy idi guy.
but why would installing injectors alter timing what so ever?
it just goes against basic diesel principle bring that is a PNL system:humm:

When the injectors get old, the spring pressure changes. New injectors will have a higher pop pressure than the old ones causing the timing to change. It wont change by much, but it's still a good idea to have the timing checked after swapping injectors.

i do not see pop pressure altering timing more than maybe .005*
i understand what you mean, but you have to think about the degree we are talking here,
Not aware what these nozzle's are set at, but lets say 260 BAR, them dropping down to 200 BAR is not going to change injection pump timing. if that is the case, timing would somewhat retarded at the moment. (in theory) but when you set timing anyway, you are setting injection pump timing already taking the pop pressure, line size, line length into factor. you do not time the pressures and when the nozzle pops off. :humm:

The science of it all leaves me scratching my head, numbers were never my thing. I know I have changed injectors before which resulted in excess smoke and having the truck retimed took care of it. These IDI injectors between age and different manufacturers can change the pressure by several hundred PSI.

The nozzles are set using BAR, it is practically impossible to happen. You could put a spring from a clicky pen in the nozzle body to hold the needle against its seat and you may be advanced .8* of timing (fuel actually getting into the engine) the ip timing would not change at all.
If timing slips that is another story. That has nothing to do with the nozzles

I don't understand any of that but I had a buddy that's a diesel mechanic look at it and he was under the hood for about an hour or so and when he was done no more smoke and it runs smooth. I asked what he did and he just said he had to adjust the injector pump and that my fuel filter gasket was bad and it was sacking air. But thanks for all the help

Glad you figured it out, sorry for jacking your thread!

No problem I may not understand what you all where saying but I will I bought this truck for the sole purpose of built a awesome diesel and to learn how to build it myself my buddy has a old 6.9 that needs rebuilt so he's going to help me built so I can learn it first hand

That is a great idea, you will learn a ton hands on, and become very good at turning wrenches, to get extremely smart, you either need ALOT of money to pour into them, or do a lot of reading, and a lot of learning? Find someone very smart than can help you, I do not mean someone that has been a diesel tech for 40 years, when it comes to the crazy stuff it is best to have a friend that may be an engineer for the diesel field, a professional engine builder, something along those lines! :tu::c::c:

He works for a local logging company fixing everything from a flat tire on a log truck all the way to rebuilding the skidders motor which he was working on then I showed up. But he's been running the shop for 15 years now I figure I'll either learn how to do it myself or go buy a bike and ride to work. Lol

It all depends how far you want to take it, I personally build engines all day :rocking:
It's not as great as it sounds :ouch: