I just had my first LP failure after 110K miles. I have read all the posts concerning the problems that everybody seems to have with these pumps and wanted to know why so much trouble with the pumps. I disassembled the pump to see how bad is the wear, and was really suprised to find that there was little to no wear on the vanes or other surfaces. The failure was the internal presssure releif valve had fallen apart. This would indicate that the failure was catstrophic and not a gradual loss of fuel pressure. Since the valve is nothing more than a spring loaded ball bearing, I suppose a failure could happen at any time, assuming this is the weak link in the chain.
I am wondering, has anybody else looked into the failed pump and discovered the same or a different situation?
'01 RAM 2500...Carter stock pump
Shand

 

The pumps will fail at the check ball and seat. I have seen one go 185,000 and fail. The brushes were completely wore out.

Were you monitoring yours with a fuel pressure guage? If so were there gradual symptoms of failure?

I have a vulcan big line kit and campaign pump for when mine gets bad enough or plain quits. I think i will replace the pump and lines with the glacier diesel kit. Since i bought the vulcan kit and campaign pump i have read a lot on the glacier kit and i feel thats best bang for the buck.

 

Welcome to DTR

That is a great post my friend, and welcome.

You hit the nail on the head. Most of the problems with these pumps are the pressure relief valves. They have been bad right out of the box,and they have lasted 110K miles. Although I can tell you it has been failing for a long time. The only way to know is to monitor the fuel pressure with an in cab fuel pressure guage. You need to order and install one right away. Your pump may have been dead for months and you didn't know it. There are no symptoms of a failing LP except when your $2,000 injection pump (installed price) burns up. The injection pump can suck enough fuel to keep running, but it had no fuel for cooling. The "extra" fuel pushed by the LP is used to cool the IP and returned to the fuel tank.

Get a fuel pressure guage right away.

Get a FASS II or Walbro replacement LP installed right way also. Don't try to figure out the stock piece of junk. It will still be a piece of junk after you are done trying to fix it.

Been there, done that.

 

Thanks for the input and advice guys. I can see you aren't foing to let me rest untill I forget about this stock pump and monitor my pressure. I expect you are right....I was trying to rationalize by making myself think there isn't any damage to my VP44, believing the pump just failed when the truck stopped running. Sure is discomforting, thinking the old girl is going to quit out in the nevada desert and cost me a fortune to get 'er towed and repaired by a crusty old desert rat. That oughta cost 'bout $3000...

I'm still looking into the old pump...'cause that's the kinda guy I am. i'll keep you posted.

New plan:
Geico266...if what you say is true, about the injector pump sucking enough to run the truck, what if I connect the LP output to the tank return line with a check valve? That way when the pump has pressure, the flow is normal, but if the LP fails the injector pump will suck air through the check valve from the return line and therefore kill the engine, saving the good old VP44.
Will it work....Hmmmmm?

 

The injector needs fuel for lubrication, run it dry aint a good idea. The vp44 injector pump needs a constant good pressure from the lift pump for lubrication. Most guys are mixing 2 stoke oil, marvel mystery oil, and powerservice in the fuel tank to help lube the vp44 also.

A fuel pressure guage is needed to monitor what your vp44 is getting. Your lift pump could have been trash many miles ago and maybe the injector pump diaphram is torn too and the timing piston trashed.

Good luck!

 

I may be missing something here, but how can you run it dry? If there is fuel to make the engine go, then there must be fuel to lubricate it. I can better understand the theory of over temperature, due to not enough fuel to keep it cool, but running dry.....I can't figure....I need more help, I guess.

 

You said you were going to rig something up to make your vp44 "suck air" . That what I was refering too.

 

oh, I see...You are saying that the short period of time that it takes for the air to rech the injectors is enought time to wipe out the pump. I think there is enought residual diesel on the moving parts for that short period to do the necessasry lubrication......No?

 

For any that are interested, I dismantled the carter LP and found something interesting. For the most part, the pump is very well built and looks like it should last the entire life of the engine. The brushes still had more than 75% length remaining. The pump had almost no wear. As I stated before, the releif valve failed. The coil spring that seats the ball is larger inside diameter that the ball size. The spring coils that contact the ball are smaller so that the ball should not be able to slip inside the spring. Guess what? You can push it right through the narrow coils with very little effort.
I beleive this is engineered into the pump purposely, for no other reason than to cause premature failure. I can not imagine any competent engineer desigining something like that in error....It had to be on purpose.
There oughta be a law.....

 

The only OEM LP I've dismantled is one that has 198,000 miles on it. No wear on the vanes or vane holder. The plastic coupling between the motor and pump had disintegrated. Found two small pieces of the coupling which appeared to be plastic. Someone told me that the coupling was made of plastic. The motor runs fine but we need to separate it and check the ball and spring for wear.

 

Here is my experience with a lift pump which should convince non-believers (like I was until I installed my FP gauge) that you really do need a FP gauge.

Ok, everyone knows that when you turn the key and wait for the light to go off, you can hear the LP running. Great, you know its working.....turn the key, she pops off and away you go, no worries right? Wrong!!!

I just installed my first FP gauge at 113 k miles. I would turn the key, hear the LP start running, and watch the FP gauge go up to 11 PSI. The lift pump would cut off, FP drop, the "wait to start" light would go off and start her up. FP goes right back to 11 PSI. Everything appears fine. If you stop here, most people might assume the LP is fine. But 10 mintues down the road, every time, FP goes to 0 and would only come back to 1-2 PSI at idle. Park the truck and shut if off for a few hours, and go through the same thing all over. The LP works great at startup and works for about 10 mintues. Without a FP gauge, you hear the LP run during the pre-start cycle and you assume it is working. Wrong! I have learned the hard way and now since I have installed the FASS pump, I have the hard start issue which means there is damage in the VP44. Question is, how much damage and when will it go south and is there anything that can be done now to prevent it without paying 2k for a new one. Anyway, point is, don't think that just because you hear a LP running that it means it keeps running while you are running down the road.

 

Hmmmm....Nothing plastic in my oem pump.

Please understand me fellows, this is not an argument on wheather the pump failing will damage the vp44 or that the need for a pressure gauge is important. We all are in agreement that the LP is a problem and that the possibility exists for further problems. It's good to discuss the inner workings of these components. Thats how improvements are made.

I would also like to know more about the inner workings of the vp44. anybody know where the information is?

 

Is there any way to replace the spring? I have never taken one apart so I do not know if this is a dumb question. It would be cool though if you could replace the spring and get more miles out of it.

My philosophy on LPs is thet they are a maintainence item. I have spent less on my CTD over 100,000 miles than any other car I've ever owned. If there is a solution to the problem and a spring is it...well it is worth a try.

Anyway thanks Shand101 for your investigation into this. I have an old LP and I have been waiting to tear it down, so I appreciate your motivation.

-Geoff

 

Sorry Hillcountry, You are thinking like an engineer now, but unfortunately, the pumps ar hermetically sealed and can't be disasembled without destroying them. Any improvements would have to be made at the factory. Best to follow the advice of others and select a beter pump. At this point, I have no idea which is better...a red one or a blue one....

No queston is dumb if you ask it ....only if you keep it to yourself

 

Neither! A pump that is cylindrical and bears the name "Walbro" is your best bet ... may even bear the markings GSL392 ... unless, of course, you'd prefer a FASS. Just my 3 short of a nickel!