Engine/Transmission (1998.5 - 2002) Fuel Delivery Question

[JGamble]

TDR,



So I didnt know whether to put this thread here, or under products, I am at a lost. So I have a DDRP on the truck in the sig line. I have religiously changed the fuel filters every 10k and had the DDRP replaced back in 09. I had a load of bad fuel in 2010 and had to replace the inj pump. So that is replaced. Now the question. Since the inj pmp install, I had about 17 psi standing and WOT about 10. I am now down to 13/14 psi at idle and am too afraid to see WOT as moderate accelerating will drop me to about 7 psi (pretty sure that is BAD for the stock VP) just to get up to highway speed. SO my first thought, the inline filter wasnt changed when i had that load of bad fuel. Could that filter be so clogged with garbage that I am seeing less numbers OR do you think my lp is going south OR something else? I would really like some feedback, this is my daily driver and want to be proactive. So I open the table to you, the most knowledgeable thread on this here internet... thanks in advance.



Regards,

J

 

[WestTN]

Did you install a big line kit? Those banjo fittings are horribly restrictive.

 

[JGamble]

I do not think so. I know for a fact I personally didnt. Due to the fact this my first and only CTD, I couldn't reference the difference between a big line kit and stock tubing. Any new ideas?

 

[Bob4x4]

Big line kit will be rubber-stock is hard line.

If your tank had bad fuel it should have been dropped and cleaned and all filters changed at that time not after another problem shows up. Don't trust a filter to catch everything when the fuel was so bad it plugged filters.

 

[CAPTPHIL]

What did you do ? Break your finger. DDRP will not support enhanced performance.
Paw Paw

 

[JGamble]

I swear PAW PAW, it held this long... . LOL. Maybe need some creative insight to get the extra 40k out of it. And yes, forum, def does have vulcan line kit. I will be buying some new inline filters tonight along with some other goodies. Keep ya posted on the outcome... . now on to other issues...

J

 

[SAndreasen]

I have the dealer. installed in tank fuel pump supplying a Dodge Direct replacement lift pump my psi wil not go below 9 under a big load and redlined on the rpm. I have edge five stage Programmer and 275 injectors the guy I bought it from had it set up that way for about 8 years. if your filter is plug before the pump that would limit your pressure I would think

 

[BMelhuish]

I too have a DDRP, and I use the inline filters. I know that the instructions tell you to change the filter every 8k, but I do mine at every oil change. I had some bad fuel a while ago that clogged the filter. If I hadn't had a pressure guage, I'd of riden the horse into the ground. After clean up and a new filter, I noticed that the fuel pressure started to drop off at 4-5k. I changed the filter, and it's back where it should be. So, now I just do it every oil change-whether it needs it or not. I do, however, start to notice a slight drop off in pressure at 3-4k. I now keep an extra filter in my bonnie kit.

 

[Bob4x4]

Are you talking about the little metal filter?if so they were never meant for the amount of flow we have

 

[KATOOM]

If you still have the OEM fuel lines and banjo fittings then you still have the shrader valve fuel pressure test ports. Go rent a fuel pressure test gauge and make sure your in-cab gauge is reading accurate. Fuel pressure gauges (both electrical and mechanical) must have a snubber device installed otherwise the hydrodynamic fluid pulses from the VP will hammer the electrical sender or the gauge itself, which will result in inaccurate or failed gauges.

If you find that the gauge is reading accurate then start looking for a blockage. IF and only if you have the fuel pressure reading from "after" all the fuel filters then either the fuel filter is dirty or the inlet line pre-screen is dirty on the fuel pump or the fuel module is crammed with crude.

 

[BMelhuish]

Guys. I no longer have an issue. I just got a load of bad fuel. I cleaned it up and changed the filters without further issue. My initial thought was to check the gauge and pump, but I was in the field at the time without many tools. I thought instead of the filter since that was the easiest possible solution. I blew out this yellow gunk. The pressure problem was temporarily solved until I could get home and do the job.

The inline filter came with the DDRP and installs between the tank and the the DDRP. Like any filter it becomes clogged over time. Fass recommends that you change it out every 8k. As I stated before I noticed that the pressure dropped a lb or 2 around 5-6k. Not significant, but I now change it every oil change. At $5 a filter, it's pretty cheap insurance. The last time I checked the gauge was accurate.

 

[KATOOM]

Good to know.
Curious though, when you said you cleaned it up, does that mean you cleaned out the fuel tank too?

 

[BMelhuish]

No. I ran it virtually dry, changed all filters, and put in fresh fuel. I decided to wait and see what happened before dropping and cleaning the tank. That was last July without a repeat performance. When it went down before, it went down fast and steadily. I hadn't gone 100 miles on my trip before I noticed that something was amiss. It was not the small drop off that I noted above.

 

[KATOOM]

I only asked because you'd be surprised how much garbage can be sitting idle in the fuel tank. The only protection you have before it makes its way up the fuel lines is the pre-screen on the bottom of the fuel module basket. If that pre-screen ever acquires a tear or separation then all that crud will quickly work its way up the fuel lines and plug things up. So if you find a lot of debris in the filters then you have to assume that the fuel module isnt stopping anything.

 

[BMelhuish]

Good point and something to keep in mind. Thanks.