a lift pump should defiantly help. it wont cure problems but it may allow you to not have to address it for a long time.

all of the hoses leading to the CP3 after the filter are capable of collapsing and causing restriction. i would, while you have it open replace them all. if you still have starting problems and you dont want to replace the CP3 then add a lift pump

 

okay so this truck confusing me! i replaced all the rubber lines going to the cp3. theres a good amount of fuel getting to it.

it thought i had it fixed yesterday when i replaced the one line that was trashed. well i couldnt get it started today unless i used ether. i tried everything again. i pressurized the tank, i tried pumping the hand primer while someone tried starting it but it wouldnt start. so i then took that line off that hooks right into the cp3. there was alot of fuel in it and it even had quite a bit of pressure built up from me pumping the hand primer.

anyways, i stuck a 2 foot piece of rubber hose to the cp3 inlet, filled it with fuel and then pressurized the line with an air compressor. and then had my brother crank it over while i held the line under pressure. he had to crank for like 10 seconds then it finally fired up. he shut it right back off after it started and then i filled the line with more fuel and had him try start it WITHOUT me pressuriizing it this time. it fired right up and we let it run for a little bit. shut it off, an then we started it again. i hooked it back upto the regular fuel line comin from the fuel filter. it would start up fine for a couple more times but then it keeps getting a longer and longer crank to start it. and then finally it wont start anymore.

so for some reason, the pressuirized air fixes the problem for a little while but then it stops working. does this seem like a sign of a bad cp3? or injectors? its about got to be one or the other unless its the fuel regulator?? but i unhooked it again like you said and that dont help.

 

rig a can full of diesel connected to the hose on the CP3. do the same test but a bunch of times, now that you have a lot of fuel. if it continues to have the same results then it is likely the CP3 or its regulator.

if it seems to start fine then it is still pulling air or it has a restriction in the lines somewhere.

it should suck about one gallon of fuel in a few minutes unless you disconnect the fuel return line on the drivers side near the fire wall and route it back to your test can.

 

I would really take it easy on using all that starting fluid

 

Finally got time to look at my truck again. and ya ive been trying to not use the starting fluid anymore after people started telling about how harmful it can be.

Anyways, i went out to the truck and held my finger over the inlet hole in the cp3 while i cranked the motor over. i didnt feel like any suction at all there. i then hooked up my hose and feeled it with fuel and pressurized it. i couldnt get it to start like i usually could when doin this. finally it started once. then tried it again with out pressurizing it but it wouldnt start. it had a little suction now on the hose but not much at all.. its like it keeps getting weaker and weaker.

What do you guys think?? im thinkin its the cp3, and im bout ready to order one and put it one but you guys Know more than me.

 

well im gettin pretty upset with this truck i bought a new cp3 and got it put on. i primed the fuel line and it fired up. shut it off and it started again. i did notice it seemed to still crank a little llonger than normal. so i drove it around and bout the tenth time i shut it off it wouldnt start. i thought i mighta fixed it but obviously not.

i noticed earlier, right after i put the new cp3 on, when watching the fuel pressure after i would shut it off that it would be around 1500 then slowly drop to bout 100. now when i shut if off its like always at 100-200. whats the deal? why did it work after i put the new on? what keeps the fuel rail holding its pressure?

also what keeps the fuel pressure up an not just letting the fuel pump back to the tank? i need ideas!!

 

check valve (ball) in the cp3. but as you replace it, it is not likely that.

my fuel pressure does the same thing when i shut it off. i think that part is normal.

this now puts me back at the beginning, where i suggested injectors. the new cp3 with its higher flow may just barley make enough pressure to fire the injectors. other times it cant.

will it now start up every time you prime it or are you still having to use ether?

 

if i reprime it, it still wont start. i cant get it to start without either.

its doin the same thing it did when i would pressure the line with an air compressor and start it. it would let it start fer like ten times after that then it wouldnt work again.

whats causing this? its like its letting a valve close so the fuel pressure is able to build up but then it starts to stay open a little more and more and soon its always open and then it wont start. i had to keep cranking on it longer and longer each time i went to start it and then finally it wouldnt start at all.

i just dont understand how injectors would cause this

 

"i just dont understand how injectors would cause this"

now that you mention it, it doesn't make sense to me ether.

the only thing i can think of now is to cap off each injector and see if it builds pressure. i guess you could also try to cap the line going to the passenger side fuel rail and see if you get lucky.

have you tried putting a vacuum gauge on the fuel line coming out of the filter yet? there is a port made for testing this located to the left of the alternator pulley. i think the max is -8 psi

 

havent tried a vaccum gauge.

went out this morning and it dint start. i unplugged fuel regualator at cp3, still didnt start so i gave it either with it still unplugged and got it runnin. i then shut it off and tried startin it and it fired right up. it was running at like 26000 psi. when i shut it off i can watch the fuel rail pressure go down but if i try starting it before it shows its below like 8000 psi itll start otherwise i gotta use either because the cp3 cant pump enough pressure up.

what i wanna know is what holds the pressurized fuel in that junction box where the lines go in and out of? what keeps the fuel from flowing straight to the tank so it doesnt build pressure? is there some sorta regulator in it?

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also the return line from that junction box splits off and goes to the main return going to the tank and the other part goes back behind the motor but i cant see where..

one more thing, everytime i drive the truck i smell burning oil. like when an old truck has a leaking valve cover gasket and it runs on the exhaust. but i cant figure out where the heck its at. i doubt that has anything to do with this, just thought id trow that out there