Hey guys i need more help!! the injection pump and lift pump are 3months old, they replaced the cam senser and not it dosent have the hot hard start as they put in a new pressure releaf valve. well it fires up no problem cold, but when its warm it cranks over about 8-10 cranks before it fires up. it has new batterys do thats good. The other thingn they said it could be would be too much fuel pressure, i have 20psi at the IP .. is this to much to have at idle? what can i do to fix this if it is the problem? its the BD maxflow pump i believe. or should i be looking for another problem? thanks

 

I don't think you have to much L.P. pressure. I would rule that out. Do you have air in your fuel system somewhere? Maybe a cracked hose or something to that exstent? I am not too sure about what else to look at just giving my
.02 about the fuel pressure.

 

ok thanks. i heard that around 24 its too much. i did have a cracked line on the fuel tank but they fixed it. also put in a new sender unit. it never had hard start before the IP and LP were replaced. i thought about the fuel leak but it wouldnt start better after sitting over night or till it cools. it would be worse the longer it sits so i dont think its that

 

try disconnecting the lp next time you do a hot start, that will tell you..... some VP44s are more sensitive to higher pressures .they are designed to operate at no more than 15 psi.

 

what he said^^^^^

 

ok they tested that and it fired up right away thats why they replaced the pressure releaf valve. i will try it again today.. also if i am running too much pressure for the pump can it hurt it? or would it be alittle better as at WOP it wont be as low?

 

it won't hurt it. but hot hard starts are not good for your starting motor.... is your lp wired into the OEM wiring?or is it wired thru a relay directly off the ign switch
the ECM cuts the voltage down so you don't get high pressures at start.....

 

im not sure it has a relay they put in on the firewall as the pump is mounted on the frame rail now. it fires everytime even when its warm. but it cranks 8-10 times before fireing.. cold its 1.5 cranks.

 

the shop thats im having trouble with (cough cough bd cough) is saying the LP is good but they think its the diaifram in the injection pump... could this cause long start? they want me to drive 4hr so they can look at it again.... they were suppost to change the pump last time i was down there...

 

Do you have the original ECM in the truck, and if so, has it been reflashed lately by the dealership. If not your ECM might being going bad. mine did the same thing that you have been describing, and a new ECM cleared everthing up.

 

it is the original one in the truck.. how much does it cost to get reflashed? when i had the edge ez chip in the truck i got a no communcation between the ecm and the IP, but i sent the IP back and they said the electroincs on the pump where bad. i havent had that code since. why would the ecm only go back after the truck is warm?

 

what about putting in a check valve? is this different from the ip overflow valve? would the check valve limit the fuel pressure into the pump?

 

anymore help on this.. the truck is still hot starting and driving me nuts. the lift pump has a relay . how do i test to see if it is cutting back the power at cranking

 

MIne is doing the same hot start problem, i don't notice it in summer, i am leaning towards maybe thin winter fuel is causing problems. If that is the case im thinking it might be my vp44, has anyone made up a gauge on one injector line to see if there is pressure while cranking. I cracked one line and it seemed like there was no fuel at first than it caught and started. Would a smarty do a reflash?

P\S starts great when cold.

 

Trying to hook a pressure gauge to the injector line would not be a good idea, it hits over 2500psi. if you think its a high LP pressure on the hot start, then unplug your LP and try starting if it fires instantly then the LP pressure is too high, if it still starts hard there could be issues else where