hard start
 

I just grind the cam plate and turned the pump up and now i have to pump the throttle to start it but after its warm it starts. I think it could be the lift pump because it runs about 12 -15 on idle but when running it dosent change much and when i get in to it goes max to 20-25 and goes down it dosent hold i checked the heater grid its fine i replace ofv it helped with smoking but i dont want to replace if i dont have to but if so i was thinking about putting a 6.0 duramax fuel pump on it because the hold up 55psi so i would kinda be like a air dog just not as $$$.

wats idle rpm.

it idles at 500-600 rpms that's never changed

i think the idle is a little on the low side. 750 to 800 seems a little better. just my 2 cents:jump:

but do u think it would matter on the start up?

yep do u know how to adjust it

no i dont, let me ask u i put a fuel psi gauge on it and my max fuel was 25psi do u think after the truck sits the pressure bleeds off and a few hour start up it has to repressure's the system and thats what could cause the ruff start?

truck should idle at 750 rpms with the truck in drive and the a/c on, after i did my fuel plate i had the same ordeal, i gotta give it a little throttle to start, no big deal and everything is normal plus it blows a little smoke when it starts :)

no like i have to hold it full throttle for it to start and its like i have to repressurize the system. i have the fuel plate slide half way now and the pump turn back down. i just ordeted a fass fuel pump to get rid of the lift pump.

fass pumps are a waste of money on 12v's. 12v's dont need crazy hi fuel pressure like 24v's do. Yes, readjust your idle. That will help. I'll bet money you dont need to have the go-pedal floored (remember; this is a mechanical truck.. it's doing the same thing w/ your foot partially on it as it is floored). I ALWAYS had to hold my foot just barely touching the go-pedal for it to start when it was below say... 50*.

are you sure you dont got no air in the lines does it like pop start with white smoke

^oh this is also a good point.. try bleedng the lines

i guess i havent bleed the lines how do u do that? and how do u adjust the idle

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how do u bleed the lines and set the idle

I think with the 12v's you just crack the injector lines and turn over the motor or use the pressurization bulb. Idle I'm not so sure; think there is an idle screw in the afc? Or around it?

WHAT?

This is not accurate info.

The "pressurization bulb"??? Idle screw on the AFC???

Even after changing the fuel filter on a 12 V you rarely need to bleed air out of the injection lines. You usually can get a 12V started and the air will gradually work its way out of the system. I have changed many fuel filters on both 12Vs and 24vs over the last 8 years and Ive never had to bleed the lines at the injectors.




Corey,

First - from the fuel pressure numbers you gave - your fuel pressure is somewhat low. iirc, it should be 22 psi min at idle and increase to around 32-34 psi under full load. It looks to me like you might need a new lift pump. How many miles are on the stock pump? You do not need an electric pump fass or duramax. The oem lift pump will support 450+ hp.

Heres a how-to for lift pump replacement:

Diesel Ram lift pump replacement


Again, how many miles are on the truck? You say you "turned the pump up" - meaning what??

You injector pump may have some wear. Its fairly normal to have to give it a little pedal to get it started. Bumping your idle up a bit may help (you should be @ 750+ rpm in gear with ac on). Heres how-to bump your base idle if you dont know how:

Ram Diesel Problems



It might be worth changing your fuel filter and cleaning/checking the pre-filter. Heres a how-to on that:

Fuel Pre-Filter Cleaning on Ram/Cummins

Another possibility is that you may be losing prime from either dry rotted fuel lines (have the rubber lines ever been changed?) or from the fuel heater (this is a very common problem as well).


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Good luck.

Oops guess cracking the injectors lines is a 7.3 thing. my bad.

Bleeding lines to the injectors is sometimes needed on a 12V but it will generally start and work the air out of the system after a few minutes.

And why is that? Why can the 12v's self bleed but a 7.3 will run like ballsack if they aren't manually bled?

I dont know the first thing about a 7.3 and its way off topic for this thread.

UMMM hey there you are wrong the 12v takes 35 psi at wot
the 24v is max of 17
get your facts straight before spilling them
and as for the fass system it is a great addition to the truck or an airdog

the 24v is max of 17
get your facts straight before spilling them
and as for the fass system it is a great addition to the truck or an airdog[/QUOTE]

Agreed The first gen 24v at much over 18psi turns out deadly for the VP44 my buddy smoked his down thata way.. and My opinion in seeing alot of these cummins or any Diesel engines fuel systems Airdog 2 is about the only way to go for a reliable fuel supply :tu:

Were talking about 12V's here - for a street driven truck this is absolutely not true. IMO, the stock pump is more than adequate for your everyday driver.

Tune the afc?

Ahh sue me. Musta been tired. It's not the fact that 24v's need a LOT of fuel; it's that the vp44 needs CONSISTANT fuel. Whereas the 12v's arent finnicky like that.

I agree. I just messed up my reasoning haha. The vp44s need consistent fuel or else they burn out.

hey bud just lettin you know if you steer someone in the wrong direction it can cause bad things just research somthing is all i am sayin

No I appreciate it actually. I knew what I was talking about, I just wrote somethign other than my brain was saying. I know its not so much the high fuel pressures that matter with the 24v; it's the inconsistency of fuel that kills them. Hence, an airdog helps worlds on those and not 12v's.

thank u that was so helpful! thats what i had thought about the air been in the line it would work its way out. on the pump what sucks is i just bought the pump becaus i plan on changing out the injectors and maybe trying to pull a few ponys out it and the other reason was we couldnt get the fuel line that my machanic that helps me wanted to get and with the fass it came with it and for the cummins pump was $365+shp so it was almost as much as the fass and the fass holds up to 600 so if i deside to go bigger i can and not have to worry about fuel i guess. do u think the ldle could have anything to do with it?

An OEM lift pump is less than $100.

Yes, if you dont have 750 rpm in gear bump up the base idle. Wouldnt tell you to do it - if I dont think it would make a difference.