2000 DODGE DAKOTA 4.7L V8 SOHC : Emission : Vapor Canister

 

If you mean it won't hold pressure, you're right. The fuel pump will run for a few seconds when the key is first turned on but then will shut off if the engine isn't running.

I missed it in your post. Are there any codes showing? When was the last time the throttle body removed and cleaned? Don't forget the IAC passages.

In 2000 it was the NV231, I have one. Mechanical shifter.

 

no codes are put out, i havent removed the tb to clean or check it since i have had the truck. By the truck not keeping pressure i mean when the truck is in the on position and i press the schraeder valve on the fuel rail very little fuel comes out, whereas when i do it to another car (in this instance a 94' plymouth van) i can start a small building on fire with the amount of gasoline i can get out. Tomorrow when i work on it i will try getting it started (i can usually get it started once every couple hours) ill press the schraeder valve to confirm i am not getting enough fuel pressure.

Now this vapor canister thing, could this cause the issues i have with fuel pressure?

The truck acts just like a vehicle that has run out of gas, this is why i think its because the fuel delivery system is at fault here and not the TB.

 

No the vapor canister is just an emissions thing it wont do anything if you take it off. There has to be a pressure release valve to route extra fuel back to the tank. Maybe there is enough pressure to pop open the valve when you turn they key that is lets off most of the pressure.
Check to see if your fuel pressure is between 44 and 54 psi

 

Well thats good news. Ill be checking the pressure tomorrow. If i am getting low pressure what else would be the culpret since the fuel pump is brand new? From my research nothing in the fuel system would cause low pressure besides blockage in the fuel line. It could be possible i knocked something loose when i put seafoam in my tank and ran it.

 

Thats what im thinking. How much fuel do you have in the tank now? also is it pretty fresh gas?

 

Could be a vacuum leak. Take some starting fluid and with the truck running, spray a mist over the vacuum lines and listen for a change in the idle. If it idles up then you have a leak in the vacuum lines or around the throttle body.

 

I had just filled the tank up from about a 1/4th of a tank the previous day that the problem occured, pretty fresh gas. I dont think its a vacuum leak there are no vacuum lines associated with the fuel line. (from what i understand). I just tested the fuel line pressure at the fuel rail. when key is turned 'on' the psi hit 30 immediatly and just started rapidly dropping to where it stayed at 15. There are no leaks and the fuel pump is new. Could this be a ASD malfunction? Im so confused by this right now. I dont think it could be a leaky injector as the truck would probably start run fine and just mis and backfire alot from my theory. any ideas?

 

You're not measuring the pressure correctly.

Hook your gauge up, then start it. With a warm engine note the note pressure gauge reading. Fuel pressure should be 49.2 psi +/- 5 psi at idle.

But, your pressure should not drop as fast as it is. The manual states it should not drop below 30 psi in 5 minutes. It can be the check valve, a fuel line, or it can be an injector leaking. A leaking injector (maybe got some dirty gas that messed it up) can make it run like crap - absolutely.

 

Well unfortunatly i truck rarely starts right now. When i dod actually get it started i will re-measure, in the mean time where is the check valve at? I looked it up on o'reillys and its cheapish so i think im going to replace that anyways just to make sure.