I know theres a ton of these posts here. But i just put in a set of ddp 100hp injectors and now the truck is hard to start. Pressure is being built up in the tank, and/or creating a vaccuum. There is also diesel vapor in the tank when i remove the cap. There is no leaks on the connector lines and tubes, so a buddy of mine said to get a new overflow check valve because that may be the cause of the truck losing prime? if that doesnt work what should i check?

 

I doubt that is the cause. most likely you didn't get the tubes all lined up and seated properly or you have a bad injector, or leaking at the head...

did you replace the injector crush seals and o-rings, as well as connector tube o-rings?

make sure the connector tubes popped all the way into the injectors, and bled the lines to get it started the first time?

 

The injectors are brand new and the crush seals were new as well. Im guessing the cause is either the o-rings on the connector tubes or their not seated right. I just need to find the time to fix it. Im just trying to see what you guys think on here so i know exactly where to start to save some time and money

 

usually always an o-ring or the connector tube didn't seat in all the way...sometimes you gotta jiggle the injector to get it to click all the way in...

also helps to use petroleum jelly on the o-rings.

 

I just ordered some new connector tube o-rings. Im hoping that will do the trick because im pretty darn sure i lined up the injectors to where the connector tubes will seat properly to the injectors. So if i put petroleum jelly on the connector tube o-rings it wont do anything funky? i dont mean to sound stupid but this has been the first time to mess with the injection system .

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but i do appreciate the responses jigabop, ill let ya know if it works

 

petroleum jelly is petroleum based just like your fuel... it is basically to help hold the crush washers in place, and to lubricate the o-rings when placing the injectors in the holes, and the connector tubes in the holes.

basically prevents the o-rings from rolling or getting pinched out of place when installing the tubes and injectors. it will dissolve away after the truck has ran for a short while. that is why you use petroleum jelly rather than grease. grease won't dissolve away without gunking things up.

 

i fixed the hardstart problem, i put new o rings in and it turns out the last two connector tubes werent seating in all the way. I was stoked about that But now the only thing that is there is pressire building up in the fuel tank. Any suggestions?

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as in there is still pressure building in the fuel tank

 

meh, my fuel tank gets pressurized by the time I fill up...

usually means your vent on top of your fuel canister is clogged. you would have to pull the bed or drop the tank to fix that.

mine is because I have a liberty fuel module which is not vented at all. I don't care though as I live in an area with mild climates...heat expansion isn't much of a problem here especially with a white truck.

 

that could possibly be it but it started doing that after I put the injectors in. when I take the fuel cap off there is diesel vapor. the pressure being created is causing fuel to leak out of the top of the tank where your return lines, vents etc. are. Im pretty stumped now.