Hi all, I hope someone can help with this. I am having a problem with my 1999 dodge ram 5.9. When the truck sits for 15 to 20 min. or longer it will turn over for 3 to 5 seconds before it will start again. I have checked the fuel pressure on the fuel rail after it has sat for 10 min. and there is none so I will turn the key to the on position once and then check it and all that comes out is air but if I cycle the key 3 or 4 times it will be solid gas. This happens wether the tank is full or not. I wonder where it is getting this air from or if this is normal. How long should it hold pressure and what is causing this to start so hard after sitting. Also If I cycle the key on and of 2 or 3 times it will start right up like it should. Could this be a fuel pump, pressure regulator, filter, or a leak some where. Any help would be very much appreciated.

Thank you very much,
Ramtuff 8

 

I'm not an expert, but what I do know is that according to my manual, the fuel systems on these newer Rams is supposed to have constant pressure. So when the engine is shut off, the system is still pressurized. In yours, the pressure is bleeding off and if air is getting in there, it sounds like there might be a leak also. But where the leak is, I don't know. The pressure regulator is what is supposed to keep the system at a set pressure, regardless if the engine is running or not. A relief valve is fitted to route excess fuel from the high side to the low side and then back to the fuel tank. A leak, to my way of thinking, might be on the low pressure side of the system, and when its shut down, the air comes back through a possibly faulty relief valve. That also might be the cause of the loss of pressure. Another cause might be the pressure regulator itself. That is located on the fuel pump assembly and is also housed within the fuel filter. The assembly is a single unit in the tank. Although the manual says the filter and regulator can be replaced, I've had mine off and I don't see how it can be done. Its a factory sealed unit. Total replacement of the assembly is about the only way to go on this one, and it can be expensive. That's as far as my thinking leads me.

I'm sure that there are a few others around here with much more experience than I. Hopefully, they will chime in with their thoughts on the subject. Good luck.

 

ljpierce_ely is right... there is only 2 places for the gas to go... back into the tank and into the cylinders... 1st thing I'd recommend is to pull the plugs after the pressure has bled off and see if any of them smell like raw gas. if they do then you might have a bad fuel injector that is stuck open...

how does it run? is there any miss at all?

 

This sounds like it may possibly be the fuel pump. When you cycle the key you are priming the pump. When you turn the key can you hear the pump whine (you may need someone to listen at the tank for you)? When it does have pressure what is the reading? Is it within spec? After it starts, what is the pressure?

 

I pulled both rails with the injectors and I could not see any of the leaking raw fuel. It will bleed down the pressure in just a couple min. now. I have followed all lines and with it bleeding down this fast I would think I would be able to see it leaking while it is running or not. As for how it runs it seems to be fine with no misses. If I turn the key one time I get about 10 to 15 pounds of pressure and if Iturn the key 3 times I get about 39 pounds of pressure.

 

I also want to thank all you guys for any help givin.

Ramtuff8

 

sounds like the one-way valve in the fuel pump assembly is bad... it's supposed to hold pressure for quite some time... I dont think it's serviceable either... I'll go check the manual and get back to you...

 

Help is what this is all about!! Not to mention sharing information. Anyway, according to the drawings in my manual, and from what I remember about my fuel tank, all the valves and connections are on top of the fuel pump assembly. The return/relief/rollover valve is located there as well. It may be servicable, but if you go through all that to remove the tank, you may want to think about just replacing the whole unit. But beware, as I said earlier, it can be a little pricey. I took the liberty of looking up a fuel pump for your truck. 99 Ram 1500 with the 5.9L It had two options. Vin codes Z and 5. I picked VIN Z.

http://www.teamautoparts.com/cgi-bin...1999&x=23&y=17

It gives 3 different pumps for your vehicle depending on cab and tank size.

Presuming the link above works, you should see the prices. I'm sure that others here have links to other parts outlets, so don't buy the first one you see. Heck, if someone comes up with a link that is less than this, I'll use theirs myself!

Good luck.

 

according to my manual... the regulator is replaceable... it says that you can pull the regulator out of the pump assembly. it's held in by a ruber gromet. there is a fuel line tube attached to the bottom and they say not to pull it out more than 3" or you'll damage the tube. cut the clamp that's on there, remove the regulator/filter and replace it...

quote from the book..." the regulator acts as a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine. A seond check valve is located at the outlet end of the electric fuel pump"

fuel pressure should be 49.2 psi +/- 5psi...

this coming from a 2001 dodge shop manual.

 

Yep, my manual says that too. But when you actually look at it, pull the tank, and try and do it, it's a real pain. The regulator is factory crimped to a plastic tube. Putting it back together has to be done right, the first time. Personally, I spent the money and replaced the entire unit. But to each his own. That was my choice, not necessarily the right one for everyone.