[DosgeThis01]

Ok so here's the deal: when my truck is turned off for over an hour it seems to lose its fuel prime and when I go to start it I have to crank on it and crank on it and it will finally start up, however If I park on a slight incline with my rear wheels at a higher elevation than my front wheels it will crank right up even after sitting for over 24hrs.

In August I installed a raptor RP-150.

This problem started about 3-4 weeks ago.

I know the problem is not within my tank because I pulled the fuel line off the tank and stuck it in a diesel can and came back with same problem.

 

[BigBadTurboI6]

The fuel transfer tube o-rings in the head are commonly blamed for this issue. 6 small 0 rings that are a but of a pain to get to but nothing crazy. Good thing is parts are cheap, couple bucks in o-rings has a good chance of fixing it if that's the problem. You have to disconnect the fuel lines into the head and pull em a bit to the side and a small flathead screwdriver will pop the transfer tubes out. Slip on the new o-ring, slip em back in and bolt the lines down again. The annoying part is getting at all the fuel lines. You'll need to pull the intake horn and grid heater and reach back while practically laying on the motor to get at the back injectors. Some searching will yield more info on this.

Could also be the o-ring/washers on the VP44 feed, return, or the return line out of the back of the head. Those locations all have the washers with an o-ring built in basically. All the parts are very cheap, just a matter of getting in there. Wouldn't hurt replacing all of em for peace of mind. Back of the head is an 18mm I believe, lines to the head are 19mm and I forgot what size you need for the VP44 feed/return lines but remember those being smaller if I'm not mistaken.


I had an issue with priming and replaced the washers at the back of the head, and the o-rings on the transfer tubes and injectors while I did my head gasket and I've been good ever since.

 

[tstevens43]

My old truck used to do this when I would park with the engine side on an incline. Check your entire system for leaks, even small leaks. I was told that the issue was air was seeping in and allowing the fuel to drain back to the tank. Check your Banjo bolts, on everything, like I said you are getting air in the system and it looses its prime. Here is a good thread you can use for reference: http://www..com/24-valve-2nd-gen-do...-loosing-fuel-prime-when-parked-driveway.html

Has multiple fixes.

 

[dirtydan]

What's the easiest way to tell if you are losing fuel prime?

I might have the same problem but I don't really notice that its on an incline. Seems pretty level. Some times it will start up fine. Sometimes it acts like its getting no fuel and just cranks and cranks.

 

[dmigz]

What's the easiest way to tell if you are losing fuel prime?

I might have the same problem but I don't really notice that its on an incline. Seems pretty level. Some times it will start up fine. Sometimes it acts like its getting no fuel and just cranks and cranks.

Typically you dont have to be parked on an incline to lose prime. My truck had this problem a while back, if it sat for any longer than an hour it would lose prime, but within minutes of shutdown it would start right away.

Number 6 connector tube o-ring was cut, check them out its a cheap and easy way before you tear into anything else.

 

[dirtydan]

Thanks dmigz!

Could you elaborate on number 6 connector tube O ring. Not really savvy on the fuel issues. Is that on the injector or some where on the fuel line?


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[gsbrockman]

Subscribing as my '99 RAM 2500 w/460k is doing the same thing.

I've had someone replace the overflow valve with little to no change.

Mine will also start better when parked on a slight incline. Seems like it has little loss of prime whenever I have a full or nearly full tank of fuel.

If it's sat for more than three days or so, I typically "bump" the starter and let the lift pump cycle to reduce crank times. The fuel filter is replaced every 7k to 8k miles (every oil change).

 

[dirtydan]

Here is a link for the rollover valve if anyone needs to replace theirs

http://oemmoparonline.com/catalog/product_info.php?products_id=78739

Also here is a picture of the fuel tank assembly. Rollover valve will be item #13

 

[dirtydan]

Link isn't working. Sorry guys.

After selecting your vehicle select fuel system and then go to page 9. Should be the 4th one from the bottom of the page.

Hope that helps.