Hi Guys I just bought a 2001 Dodge 3500 5 speed manual 74000 miles. The original owner never drove it much and when I got it I noticed it wouldnt rev above 2400 rpm. I put on a fuel guage and it has 14 psi at idle or when i bump the key and around 5 to 7 at wot under a load. I took it to autozone and had the codes checked and there was none. any advise on what to check or do. I put on a new fuel filter and nothing changed.

I am going to assume the truck has the oe lift pump on it. If so an after market lift pump would be what you need to get the pressure up and keep it up. You need to see what kind of lift pump you have. When you bump the starter can you identify the location of you r pump? If it is the oe it is either going to be on the block just behind the filter canister. IF it is a dodge after market it is going to be in the tank. Neither is good and are notorius for weak pressure. Fass and Air Dog both also make a block mounted pump, they should be easily identified by their logos. Another thing you could do for us is to go to the user cp and fill out your signature with what ever you know about your truck,if its stock thats fine, just put that in there. everyone can see what you have any time you post.Congrats on the new truck, sounds like got a very low milage one.When you say it want rev above 2400, do you mean you can put the pedal to the floor and it goes the 2400 and no further?

It has the lift punp in the tank and when I bump the key it goes to around 14 psi and yes when I push the pedal to the floor it will only rev 2400 the fuel pressure goes down to around 5 psi and comes back to around 10psi. Thanks for the reply

Lift pump is dead... VP44 might have some damage on it. The VP44 should rev clear to 3K or a bit more. But free rev is not a proper fuel pressure test... As in my video you only see about 2-3 PSI drop from idle to WOt which is normal any more that 5 PSI drop or pressure drop below 10 PSI is a instant fail.

http-~~-//www.youtube.com/watch?v=grl72Up-8T0

You want to keep it in the green.

Looks like lift pump time I sure hope the VP44 is ok Im not sure how long they have been driving it like this. I took it for a drive with the fuel gauge hooked up and it dips down to 5 psi at wot.

Looks like lift pump time I sure hope the VP44 is ok Im not sure how long they have been driving it like this. I took it for a drive with the fuel gauge hooked up and it dips down to 5 psi at wot.

ok - dont kill me but going to throw this in here. IF his truck has no codes and he is mainly getting +10-14psi fuel pressure - why do we think its the lift pump and VP44 ?? I know the fuel return only happens at over 10PSI ... but it doesn't mean he HAS done damage to the VP44 right ? Especially with no timing cant advance errors or codes So why wouldn't we look to more normal things like ....put in new air filter and new fuel filter or at least clean them ... Im just confused specifically what he said here MUST be a lift pump and vp44 issue. ? Doesnt the factory lp only run at like 5-7 psi at WOT ?

I did put a new air and fuel filter in the truck but didnt help me any. Im pretty much at a loss since I just got the truck and don't know the history.

--- Update to the previous post...

I checked the codes by turning the key and also took it to autozone twice and they hooked it up to check the codes and nothing so is there any other way to check for codes on a diesel or is that all i can do.

Well lets ask this question then. When you say that you rev it and it drops to 5 psi then builds to 10 psi are you just free reving it in the drive way? IF so go out and hit WOT under load and see what the pressure is. Chance are you are going to see near 0.It is possible the VP will run quite a few miles more. Mine lasted for 70k after lift pump (oe) failure and survived the intank pump for a while before it started acting up. I put a booster pump on it that helped but some damage was already done. It held up for the last 40k of the 70 before I replace it. My thought is the lift is crap but the vp might hold together for good while longer, it is hard to say. I was not saying do them both at once. ther is hope for the vp. I guess I just dont trust the oe lift pumps especially the in tank ones.

It drops to 5 to 7 psi at wot while driving. I think I will put a new lift pump in and see what happins. It wouldnt hurt to upgrade the lift pump anyway. I will just drive it till the vp44 loses performance or goes LOL then replace it when my bank account recovers

I use to run factory Carter lift pumps with a big line kit they will hold well above 10 PSI at WOT. But even the Carter lift pumps won't last very long I ate three lift pumps in about 60K miles costing nearly $200 a pop. After that I upgraded to a AirDog and never had to worry about it again...

I remeber looking at the new fangled lift pumps and at $500 I thought they were quite pricey. But after an in tank pump $900+ and a booster pump to help it $250+ it they started looking pretty darn cheap.

Well, I own a lower mileage 01.5. I had a wiring fault shut down the stock lift pump which I converted with an AD150 & big line kit. But my VP44 seems to have survived it. My suggestion is to get the trouble prone stock lift pump out of it, before it costs you a VP44. Your IP might be just fine.

Im thinking of going with the Airdog system. It seems to be the choice of diesel truck owners, plus I seen fass has no warrenty. Any thoughts.

Fass has a lifetime warranty just like AD. Read at the bottom. http://fass-fuel-pumps.com/fass-fuel-pumps/fass-fuel-air-separation-systems-spec-sheets.htm

i would suggest before replacing the vp44, do all the fuel mods needed to upgrade, then try reset the APPS. (accelerator pedal position sensor) When my vp went out the door i could still rev to the limiter (for testing) so if he has no codes could possibly be the APPS or its blocked to where the pedal isnt going all the way down.Would hate to see someone replace a VP when it could have been something else. VP should be last IMO on this situation.Thoughts anyone?

Well got my new airdog system on today and it still rev's only 2500. I checked all lines and its getting 15 to 17 psi it barely drops at wot. :banghead:

sound like your fuel pressure problem is solved, now you need to get your codes read and see what they are pointing to.

When suggesting big purchase buys for repairs I like to have two smoking guns. In other words we already got a low fuel pressure problem which is the first smoking gun. So now lets check error codes write them down then clear then out and go for a right and then check again. If we come up with a second smoking gun (P0216, 1688, 1689, 0251, 0252, 0253, etc) then I would say its time for a new VP44 injection pump.

He already stated that there are no codes. I agree with the apps reset. My truck with a weak lift pump only pumping 5 psi wot would run 3000 rpms down the road. I dont think his revving issue is related to fuel pressure. Granted it is low and could have caused some damage to the vp, it should still rev. nNow he has got the fuel pressure in check, we shouldnt ask him to spend a fortune on a vp just yet. There are many other fault areas that can be checked. Starting with the apps. You should get a scanner that can do live data and check the throttle percentage as you push the pedal down. It should go from 0 to 100 percent. If not then you could have a bad apps sensor.

I went back and re read this thread and did not see where anyone told him he needed both a lift pump and a VP. The intank pump he has was pushing minimal pressure and I have seen and experience bad things with that pump. It was also mentioned that some damage to the VP might have already occured, but no recomendation to buy one. My VP survived that and lasted another 70k after restoring good pressure to the VP. Other folks have had the same result. Like MIke said two smoking guns might confirm it.Vdub, Have you reset your apps since installing the AD? If not, disconnect the battaries for about 30 minutes then reconnect them. Turn the key to the on position(no start) and slowly depress the throttle to the floor and slowly release it. Turn the key off and you are done. Then see if it will go beyond 2500 rpm. While you are out have some one check for codes again. Maybe someone has one that can read live data and see if your apps is sending the proper signal.

I went back and re read this thread and did not see where anyone told him he needed both a lift pump and a VP.

Correct, just making sure he isnt mislead by mistake.