Engine/Transmission (1998.5 - 2002) Fuel pressure going up.

[JTroiano]

OK, usually everybody has low fuel pressure problems. I am having the opposite problem. My fuel pressure is almost 30psi at idle some times. I have a gauge mounted to the pump. When the fuel pressure goes down to normal 25-26psi I can hear the pumps laboring. It would almost seem that the grid heaters are on. I measured the voltage at my Carter pusher pump and it will drop to about 12. 5 volts when I can hear it laboring and then go to battery voltage and then the pressure is high. I don't have any idea about this one and am waiting for something to crap out. I have a separate relay being powered from the stock fuel pump to run the pusher pump. I though maybe it was just getting a little cold out but after running for about 2 hours it still acts up. The coldest it has gotten is about 35 degrees. It is like the injection pump is upping the pressure some how. I didn't think it could do that but maybe some one knows. Any help or ideas would be great.

Jon T

 

[jmeehan]

How's your fuel filter look?

 

[Gary - K7GLD]

YUP - sounds like your fuel filter downstream from your guage is getting plugged, forcing increased system pressure back to the pump... That's why it's a good idea to put the guage at the inlet to the VP44 - you get pressure readings where they are most important - and still get adequate indication as to when the filter is getting plugged by watching for DROPPING pressure...

 

[jerryrigg]

First are you sure the Gauge is accurate... who makes it and what is the error tolerance at full scale deflection... most gauges are designed to be most accurate at mid-scale or full scale... . over time this error can increase... if yours is designed for mid-scale you could have a full scale error exceeding +/- 5psi... do you still have the schrader valve in your system... you might want to get another gauge like Briar's to check the system and verify the gauge. .



But also look for a blockage in the fuel lines

 

[Rob Thomas]

Or, it could be a faulty pusher pump, which was the case with mine. Like above, it started climbing, and about a week later it was at 31psi, pre filter AND post filter (yes I have 2 gauges).



I bypassed the pusher, and whola, 11psi across the board. Took the pusher apart, to no avail, smacked it with a hammer, reinstalled it, 31 psi. I decided to scrap the pusher, stock lift-pump, and stock lines.



Made an entirly new fuel delivery system.



Later, Rob

 

[andrewkoperdak]

Check your pressure using the schraeder valve and a mechanical fp gauge. You will know for certain what is going on then. The mechanical gauge can be had at you local parts dealer for cheap. I used this process to find that I had air trapped in my fuel line.



R,

Andy

 

[JTroiano]

Thanks for all the posts. I get my fuel pressure reading from were the schrader valve used to be after the fuel filter. It is a Isspro gauge 0-30 psi. The fuel pressure sure seems to be fluctuating a lot more and I would suspect that the pusher pump may be starting to take a dump. Have all the tools with me to by pass if needed and an extra pump for the main. I need to get a new system. Theses Carter pumps S**K!

Jon T

 

[Gary - K7GLD]

"I have a gauge mounted to the pump. "



Then:



"I get my fuel pressure reading from were the schrader valve used to be after the fuel filter. "



My mistake - I thought you had your guage mounted at the pump, not AFTER the filter...



Ya gotta stop throwing us curves like that it's HARD to shoot advice at a moving target!

 

[JTroiano]

I'm sorry Gary, I have a hard time getting my thoughts across clearly. On the way home tonight it almost hit 30psi. When it reads normal I could swear the battery voltage is low, like the heater grids are turned on. When it does this I haven't been able to check them with a DVM but I have a funny feeling I might have two separate problems going on. Thanks again for the input.

Has any body found a pump that is good and that will flow enough? I don't want to spend another two or three hundred dollars for another piece of crap.

Jon T

 

[Bigsaint]

Has any body found a pump that is good and that will flow enough?

The PE pump I'm using is doing fine, has a bit over 7 months under it's belt now. Good thing is that it comes with 2 year warranty, un-conditional mind you. I'll throw a parade is it makes it through the winter



http://www.productengr.com/PE_4300.htm





Scott W.

 

[Rob Thomas]

Thanks to Scott (Bigsaint) I'm using the same pump as him, but only for a few weeks , seems to be great so far. Thanks again Scott.



Later, Rob

 

[JTroiano]

Thanks for the info. I am not trying to be disrespectful but my Carter pumps lasts 7 months. I want something that will last for a 100k. I'm taking my kids over the mountain this weekend and going to be about a hundred miles in the woods in freezing weather and just a little worried about the pump. I could probably get it fixed out in the woods but it wouldn't be fun. I'm thinking about researching a pump from another diesel truck. Any ideas? Not just the other two truck brands but maybe a big rig electric pump? Thanks again.

Jon T

 

[Motorhead]

Could your pressure relief at the inj pump be sticking and not opening?

 

[JTroiano]

Motorhead, I was thinking about that but I would think that it would get lower because of wear but I guess anything is possible. I have to wait until after this weekend to check anything out. I think the first thing I'm going to do is by-pass the pusher pump and see what my pressure is. Then if it is the pusher pump causing the problem I will probably look into a new fuel system because I don't think the Carters are up to the task. I like the looks of the pump Bigsaint is using but I don't know, seven months is not a long enough test period for me. I'd be willing to put up some cash with some other interested people to have one of the PE pumps that are being used by Bigsaint or someone else to have it sent back to the factory and disassembled and checked for abnormal wear. It would maybe prove that they are the best pump for the job. The motor looks a little like the Mallory pump if I'm not mistaken and they are having problems with the brushes. I am just frustrated with the whole lift pump problem.

Jon T

 

[Bigsaint]

Jon, I know what you mean regarding the frustration level. The problem with finding a pump that will last ( we all want one that will go 100,000 ), is that it takes real world testing. I think you idea of pulling a used PE pump and seeing how it's wearing is a good thought, but it's 12F outside as I type this and I don't want to pull the pump until the spring thaw ( lack of a garage that will fit the beast). The workmanship on the PE pumps is second to none IMHO. So are the folks at PE. When I spoke with them initially they said that, if the pump started to show signs of failure, they would next day a new pump to me so that I could remove the existing pump and send it back to them for their own failure analysis. That, coupled with the 2 year warranty, convinced me to try it. The motor on the PE is built for constant duty, so they say. It's is also a vaned pump, rather than a geroter design that the Mallory uses.



In my own experience, the cold winter months seem to be the hardest on the pumps. If you are undecided, why not just slap another OEM pump in for now and watch for continued feedback from us that are running the PE ? That's about the best advice I can offer right now.



The only other pump that I know of and that is doing well( other than the twin pusher pump set up) is the Aeromotive that CSutton is using. PM Chris if you are interested in the details of his install. I believe that Chris has over 2 years ( or close to it) on that pump.



Scott W.

 

[JTroiano]

Thanks scott, I have one more new Carter to use up. That should get me throught the winter months. It may not even be the pump but it sure is looking that way.

Jon T