Ok I posted a thread about a hesitation issue and just got around to doing a pressure test. When my truck is at idle the needle on the pressure gauge goes crazy, however once I rev it up it stays at 50psi. Now since my hesitation only happens at normal acceleration and goes away when put on the rug, would this point towards the pump itself? The truck also idles rough and I am hoping that it is just the filter and not the whole pump assembly. From what I have been reading in the repair manual, the fuel filter acts as a filter as well as a pressure regulator. Would you guys say it is the filter/regulator or the pump? The filter/regulator is only $65, so I hoping that is the problem. I presently have the box off the truck so I can easily access and diagnose the pump assembly. Also, before anyone jumps down my throat, yes I read through archived forums to find an answer. Unfortunately I didn't find anything or anyone who had the bizarre pressure reading that I have had. Thanks for reading this post and I do appreciate anyone that can give me advice.

 

It should be steady pressure at idle and shouldn't change hardly at all when you get on it. Maybe a tiny bit after the initial pedal push, but it should recover after a fraction of a second or less.

If its not a steady pressure at idle, something is up with something (there's a profound statement for you). Sorry I can't help whether its the pump itself or the filter part, but thought I'd chip in by saying you're right, you have an issue. I've always been told you can't replace the filter/regulator separately, that you have to replace the whole pump assembly, but I've never done it myself.

 

Hey thanks, it didn't seem right to me either and the fluctuation in fuel pressure was causing miss fires when I had the scanner on it. I guess the reason I figure it is the filter/regulator is because when I rev the engine up it stays at a constant pressure. As for changing it, yes it can be replaced. Here is a link to a site to buy one http://www.car-stuff.com/carparts/do...339831656.html
I called and my local dodge deal has one in stock, I will post pics of the replacement. Thanks again for the quick reply.

 

From my understanding of port injection, the regulator should be vacuum operated and located at the return port of the fuel rails. Sounds like a FPR anyways, just remember if you pump was bad or your fuel filter (in tank not servicable) was bad, you would have performance up to a certain percentage of fuel flow rate where it would nose dive the pressure.

 

That is awesome, I don't know how many times I have heard that one. lol

Well I am just going by what I see and what is in the haynes manual that I bought. My truck has a fuel filter/regulator assembly on the top of the fuel pump, which is serviceable and easy to get at. Well it is easy now that I have the box off. The way it was explained to me was that there is a spring loaded valve inside of the filter assembly that acts as a regulator and may possibly be warn out. This may explain the fluctuation in fuel pressure, I hope. I am just debating whether or not to just bite the bullet and change the whole pump or not. According to NAPA they can sell the pump with filter in it but can not sell just the filter. I have to get that one from Dodge. You would be surprised how easy it comes out, just a little pry with a screw driver and out it comes. It just sits down into a rubber seal on the top of the fuel pump. Anyway, I am going up to the shop to work on my truck and will post some pics of the filter/regulator assembly because everyone I chat with tells me it doesn't exist. Is it possible it is only on v-6 models? Or would it being Canadian make any difference? Thanks for the help.

 

Ok guys I took a few pics of the fuel filter/regulator and thought I would post them due to the fact that I have been told by numerous people that it doesn't exist. So could the regulator part of this assembly be causing the erratic fuel pressure. And I mean erratic, the needle on the test gauge goes crazy until I give it throttle, then it stays at one pressure. When I have the hesitation problem I shove the pedal to the floor, it takes off and works great. Thanks!

 

The part you are holding in your hand is the regulator assembly.

You really should blow the dirt off of that before taking it apart.

 

I wasn't worried about it because I am going to take the tank off and clean it all out anyway. The part is also a filter, my local dodge dealer has it listed as that and the haynes manual I have says the same thing.

 

Hey there, did replacing the fuel pressure regulator help with the erratic reading? I am having the same problem with my truck.

 

Hey, no the issues I was having actually had absolutely nothing to do with the fuel system. It turned out to be the front O2 sensor. I went to the parts store and they actually told me that dodges are famous for temperamental O2 sensors. And before you ask, no I did not have a check engine light but just as soon as I changed the sensor the truck ran perfect. Hope this helps and let me know if there is anything else.