Stock Carter Fuel Lift/Transfer Pump...Replacement Quesiton

[keithb7]

Hi folks I own a 1998.5 24 valve 2500. I am currently replacing the stock Carter fuel lift pump, (Right rear side of block) with an equivalent new replacement. This is a preventative maintenance measure as pump on there now is seven years old and making 8 psi under full load. I an interested to see what pressure a new pump will make. New pump is just being bolted down now. Is it ok to install this dry? Will it prime itself once I hook everything up and turn on the power? 

 

I know about the upgrades for these lift pumps. I do plan to upgrade to a more reliable pump with better flow rate, in the future. For now just going with stock until I decide on an upgrade system.

 

Thanks for tips on priming it or not. - Keith

Edited October 6, 2018 by keithb7

[Mopar1973Man]

Problem is you need 14 to 20 PSI for optimal VP44 lifespan. Below 14 PSI the overflow valve is closed. Stock Carter might barely do 14 PSI at idle but will drop it 8 PSI because the plumbing is too small.

[keithb7]

Thanks. Any tips on the priming? Is it required?

[greed]

Including the original, I went through 6 of the Carter pumps. As I recall, even with a 3/8 line kit, about the best I saw was 12PSI at idle. It would drop to 7 or 8 under load. Then the pressure would start to fluctuate. When the pressure started to fluctuate, I changed out the pump. I had bought 4 at the $64.00 campaign pump price. The last one I had to pay the full $180.00 price. I went to an aftermarket pump, and it holds 15PSA continually. Loaded or unloaded.

[keithb7]

Thanks Greed. Did you have to prime the original type Carter pump when you installed them?

 

[greed]

No, I cycled the pump with the key a few times. I had mine mounted back by the tank. Changed one on a friends truck, and we had to crack a couple of injectors to get it to start.

[JAG1]

Yes you have to prime the system. I usually bump the starter a few times having two of the injection lines loosened, just a little, to help refill the factory filter and let the air out. When you see fuel weeping out of the loosened H/P lines re tighten them and crank over till it starts. Rough running at first it will smooth out as long as there are no other leaks in the fuel system.

 

Side note; even with a big line kit installed on my truck, the carter pump could only marginally keep up with the requirements of the VP44 injection pump. Also, I avoided driving my truck till I got a fuel pressure gauge installed.

 

 

Edited October 6, 2018 by JAG1

[015point9]

Not sure how much of my post you can apply to your set up.  I have airdog 95 and have carter pump as a back up only.  Using shut off valves I can install carter in 20 min.  Never had to prime but I dont lose any fuel out of the line because of shut off valves.  My carter 12 psi most and wot 7 psi.  My fuel line bypasses OEM filters,  line goes from pump to vp44 with filters on airdog pump.  Carter pump just keeps me from getting stranded somewhere. 

[keithb7]

Well, the experience keeps piling up. I learned a few things today about my first owned diesel truck. As mentioned, I had planned to replace the stock type lift pump with another stock type. I had recently acquired the truck. I had recently learned about the problems with the lift pump on a few web sites like this one. I had no idea what my fuel pressure was between the lift pump and high pressure fuel pump.

I had read a lot about the update pumps from various manufacturers. I saw a stock lift pump, Carter brand, new on Rock Auto for a good price. I figured what the heck, I'll change it until I get more time to research the various upgrade pumps. 

 

I also ordered the pump pressure test gage tool from Gino's Garage. It all arrived in due time. With Gino's gage, and the questionable pump on my truck,  I recorded 8 psi under heavy load up a hill. I figured, it's not the minimum, but not great either. So I'd proceed to put the new Carter pump on, and see if there was any psi improvement. That was to happen today.

 

I read over the instructions in the manual and got started. I decided to swap the pump from working above the engine. It was not too hard to do while standing on a short foot stool. I could get it done. The old pump came out quick. New pump a little awkward to line up the fuel lines, but I got it together. Upon test, I was sucking air in somewhere. Lots of air. I hooked up a clear hose to the test port on the filter housing. I could see tons of air and little fuel moving up the line to a bucket. I re-inspected everything I had done with flash light and mirror. I could see my fuel line to the intake of the carter pump was not squared up. I was sucking air there. I tried to tighten it some more. I could see things were not lining up. Darn it. I figured I must have cross threaded the fuel line mount bolt into the pump housing. It was not difficult to line up that bolt when I put it in. It went in so easy by hand, it did not feel cross threaded.

 

 With the new pump removed, I confirmed that yes I had cross threaded the bolt. M12 x1.5 I believe it was. I did not have the right sized tap to clean it up. Damaged threads were on the firewall side of the pump. It was hard to reach, unable to see, doing it by feel,  while also lining up the 2 sealing washers. That's what caused me to cross thread it I guess.Oh well. You live, ya learn. That Carter pump housing is awfully soft metal I estimate. It was nothing, to cross thread it seemed.

 

So the old pump is back on and now I will shop for a new high volume pump to upgrade. I did run more fuel through the clear hose off the filter housing with the old pump back in. I was impressed. These things move a lot of fuel. I can only image the the amount of fuel the upgrade pumps must move. 

 

Good or bad, it's all experience. I would still much rather do it myself than pay a shop to. Truck is running and up now.

To complete my original question, the carter type pump is self priming. No need to put any fuel in it before installing. It will suck and even move air and create a vacuum to pull up fuel from the tank.

Edited October 7, 2018 by keithb7

[Mopar1973Man]

9 minutes ago, keithb7 said:

I recorded 8 psi under heavy load up a hill. I figured, it's not the minimum, but not great either.

 

Well below the minimum. The new standard is 14 to 20 PSI.

 

 

 

[keithb7]

Thanks for the updated info on the fuel pressure Mopar1973man. I think I have settled on the FASS DRP pump. Also an A-pillar set of gauges.

[Mopar1973Man]

1 hour ago, keithb7 said:

I think I have settled on the FASS DRP pump.

 

I would suggest against it. Typically the DDRP (Dodge Direct Replacement Pumps) don't address the plumbing issues. So the pressure problem will continue. Also the DDRP pump don't isolate the ECM from the pump so if the pump shorts out you take the risk of eating a ECM. There is no fuse or relay for protection like the bigger kits like AirDog 150 or FASS 150.

 

 

You need a fuel system that replaces everything from the fuel tank to the VP44. So you going to buy a good high power fuel lift pump but force it to suck on a 6mm straw and push fuel through the choked banjo bolts. Not a good idea. Good way to experience this is take your favorite beer put it on the back bumper and get some 6mm tubing and suck your brains out to get your beer. The stock fuel pickup module is also too small to this why most have either modified the stock fuel module or just installed a drawstraw. 

 

[keithb7]

 This is becoming a bigger issue the more I learn. LOL. I will check out the FASS 150 and the Airdog 150.

Thanks.

Edited October 8, 2018 by JAG1

[Mopar1973Man]

I learned this stuff the hard way. I did the Vulcan Big Line Kit. Then relocated the stock Carter pump. Worked good but the pumps where junk. Then upgraded to AirDog 150 but ran in on the stock fuel sender but the pressures were very wild. Once I installed the draw straw I've had zero issues for 13 years and 250k miles.

 

I've installed a few DDRP pumps for locals and all them failed the same way with pump failure.

 

Calculated max flow at the open end of the stock banjo was like 50 GPH really sad to see performance 100 GPH pump pump choked to 50%.