Lost power

[JCLOPP]

I have an 02 2500 6 SPD manual tranny. Bone stock except cold air intake. Recently truck seems to be losing fuel prime and I can find nowhere it is going. Truck sits overnight and fuel filter housing will be empty causing very hard start problems. When I do get it started seems to idle fine. When I drive it sounds like turbo is not coming in until upper rpm range. Truck will barely pull itself up even the smallest of hills. Lift pump is new (one mounted on engine) and seems to be working fine fills filter housing in under 10 seconds. No DTC codes. Any ideas or suggestions would be greatly appreciated. 

[Mopar1973Man]

Fuel pressure? You need to have a gauge in the cab. I'm going to bet the fuel pressure is really low. You need to keep 14 to 20 PSI while at WOT going down the pavement.

 

As for the loss of fuel prime that is because there could be air leak in the injectors, injector lines, crossover tube o-rings, return banjo at the back of the head. Suction line air leak. Fuel drain on the filter is leaking. Suction side leak are tough because they never drip on the ground. You'll need to put 1-2 PSI of air pressure the fuel tank and hunt for the leak in the system be like a moist spot.

[JCLOPP]

Headed to parts store to get a fuel pressure gauge now. If fuel pressure is low what could cause that as I said the lift pump is new but I don't think this was one of Dodge best designs for lift pump. Would love to put FASS system on but budget constraints make that impossible. Is there an alternative solution that is more economical than a FASS fuel system? Thanks for the advice I will have fuel pressure gauge Installed shortly.

 

[dripley]

You answered your own question on the lift pump, Not a good design. Bad enough that after some time Dodge would not even use one for replacement of a bad one. That is how the intank pump for a 2nd gen was born. Have you parked you truck and just let run and looked over for fuel leaks? Not sure how the filter canister would completely drain with out it leaking on the ground. Not sure but I dont think you can siphon that empty.

 I had hard start issue a few years back and it was on the return line from the head and the VP. It was allowing air in and draining the fuel from the VP. That seems to be a common spot, but as @Mopar1973Man mentions above it can be in other places also. And with the weak power could be from a suction leak letting air in the fuel stream.

[JCLOPP]

I dont think the filter canister is going completely empty maybe I misspoke I mean it is not full as it should be and the return line from head is a good place to start looking. I am replacing the fuel lines with marine grade rubber hose from the tank forward today just to be sure I don't have an air leak there so I will see if there is a problem there. Does anyone know if there is a good replacement or perhaps a supplement pump I can add on that will help get fuel to the lift pump perhaps then it might last longer or maybe even bypass the factory lift pump all together? A FASS system is out of the question on my bidget.

[Mopar1973Man]

Make sure its 1/2" fuel line...

 

Edited August 19, 2018 by Mopar1973Man

[dripley]

I ran a booster bump on mine for quite a while along with the in tank pump. It served me well and fixed some issues with low pressure I had. It did work but I never had much Idea of the pressure nor what would happen if the other pump failed. You can do it but I would consider it a temporary fix and install a fuel pressure gauge to keep tabs on it. I did replace mine about 3 years later with a full AD pump, 1/2' lines and a fuel pressure gauge. Just did not know much about the fuel system back then.

[Haggar]

I have noticed two areas that can easily cause a loss of prime, causing a long crank cycle.

 

The first is the seals on the banjo bolt on the back of the head.  Its a pita (especially with my elephant arms and hands.) 

 

The other (and the easiest to check) if you still have the stock quick connect from the pump to the inlet of the fuel manager.  This O-ring is awful.  It will not leak under pressure, but will under vacuum.....  so the fuel runs back to the tank....   try a glob of grease on the nipple and see if the problem goes away for a few days.

 

For me those just cause long cranks.  I run fine after it starts (no power loss)  but my pressure stays up.  It looks like you may have a combination problem (leak and pump)

 

Otherwise....  its all the things Mike pointed out.  Hope you find it!!!!

 

GL HTH

 

Hag

[Mopar1973Man]

1 hour ago, Haggar said:

This O-ring is awful.  It will not leak under pressure, but will under vacuum.....  so the fuel runs back to the tank....   try a glob of grease on the nipple and see if the problem goes away for a few days.

I forgot about that. The grease trick does work for testing for suction leaks. Typically it will create a seal for a temporary time and fix the problem then return.

[JCLOPP]

By fuel manager I assume you mean the filter housing. I do have stock nipple from lift pump to filter housing will check both of those today. Dropped fuel tank yesterday so clean it shined inside there went ahead and repaired fuel level arm while there. I did find an aftermarket diesel transfer pump that runs around 10 psi. I also located an aftermarket fuel filter housing that I had tucked away until a day like today. My plan is to add the filter to the frame rail just past the tank and then place the aftermarket pump between the factory lift pump and the newly added fuel filter and see if pushing the fuel to the lift pump helps. Bought new gauge to monitor the fuel pressure. Can anyone tell me where to hook the copper line in for the in cab gauge? 

[JCLOPP]

Okay all sorry for the late reply I have been in hospital and havent had time to post. Just wanted everybody to know the outcome. Losing prime was the Copper washers bad on fuel inlet and return at VP-44, I replaced these no more losing prime. The loss of power was the MAP sensor (I learned that on a diesel this is same as the boost sensor) New sensor was over $200 at parts store so before replacing I removed the sensor and used an entire can of map sensor cleaner on it (be careful not to damage the little probe in end) cleaned all the carbon buildup from sensor replaced it and it worked beautifully. Removed the factory lift pump from side of engine and replaced with aftermarket pump mounted to frame rail between tank and filter housing, also bought and installed filter and filter housing between tank and new pump (you can never have too much filtration) ran new fuel line from tank to factory filter housing and installed new pressure gauge in cab. New pump runs 40psi at idle and around 25 at WOT. Truck runs like a new one so far no problems. Thanks to everyone for the advice and suggestions. 

[IBMobile]

I hope all is well after the hospital stay.  It's good to hear you have the truck running tip top again with out a lot of cost.

One thing though is that the fuel pressure is way to high.  You want to get that pressure down to about 20psi at idle and no lower than 14 at WTO. 

[Marcus2000monster]

What lift pump did you get? 40 psi is way to high. Like Martin said 17-14 are your majic numbers. 

[JCLOPP]

Aftermarket pump by Holley. Same exact one with same pressures a friend of mine has been running on his 02 for three years since I have known him, he has basically exact same truck I have he ran 1/2 " line same pump and same pressure as mine his has been 3 years and never missed a beat. I might see if I can lower the pressure some it has two adjustment screws on the regulator. 

 

[Marcus2000monster]

I would be supris d if that pump lasts long. Look into the Airdog raptor series they’re a high quality affordable pump. Either crank that pressure down or get a better pump unless you have $$$$ for a new IP. 

[Mopar1973Man]

Kind of risky being above 20 PSI some people have had the front seal blow out from excessive fuel pressure. So have ran 40 PSI but just risky.