lifter pump?

rubicondon53 · **Joined:** Fri Aug 25, 2006 6:37 am **Posts:** 15

Hey Guys !! My wifes CRD has been performing flawlessly now for 95,000 miles, until Monday....
It will run not much over idle, and not much over 20 mph. Tromp on it, and it stalls. wait a bit and it fires back up.. first thing I did was replace the filter, to no avail,, same symptoms,,, I've narrowed it down to the lifter pump. Any thoughts??

CATCRD · **Posted:** Sat May 19, 2012 11:36 am

I'm not quite sure what you mean by narrowing it down to the lift pump. A stock CRD doesn't have one. Some people add one to get a more reliable flow of fuel through the filter and avoid sucking in air. Air could be your problem. Have you checked the electrical plugs on the front of the filter head? Pull them out and look for leaks, maybe give the primer a pump or two.

rubicondon53 · **Joined:** Fri Aug 25, 2006 6:37 am **Posts:** 15

CATCRD wrote:

I'm not quite sure what you mean by narrowing it down to the lift pump. A stock CRD doesn't have one. Some people add one to get a more reliable flow of fuel through the filter and avoid sucking in air. Air could be your problem. Have you checked the electrical plugs on the front of the filter head? Pull them out and look for leaks, maybe give the primer a pump or two.

wait a minute,,, isn't the stock fuel pump on the crd located in the fuel tank?

rubicondon53 · **Joined:** Fri Aug 25, 2006 6:37 am **Posts:** 15

CATCRD wrote:

I'm not quite sure what you mean by narrowing it down to the lift pump. A stock CRD doesn't have one. Some people add one to get a more reliable flow of fuel through the filter and avoid sucking in air. Air could be your problem. Have you checked the electrical plugs on the front of the filter head? Pull them out and look for leaks, maybe give the primer a pump or two.

CATCRD wrote:

I'm not quite sure what you mean by narrowing it down to the lift pump. A stock CRD doesn't have one. Some people add one to get a more reliable flow of fuel through the filter and avoid sucking in air. Air could be your problem. Have you checked the electrical plugs on the front of the filter head? Pull them out and look for leaks, maybe give the primer a pump or two.

i just replaced the fuel filter this AM,, primed all the air is out of the lines,, it idles perfectly,,, where else might it be sucking air and only at higher rpms? I'm definitely lost on this one!!

ChooChooman74 · **Posted:** Sat May 19, 2012 6:09 pm

rubicondon53 wrote:

CATCRD wrote:

I'm not quite sure what you mean by narrowing it down to the lift pump. A stock CRD doesn't have one. Some people add one to get a more reliable flow of fuel through the filter and avoid sucking in air. Air could be your problem. Have you checked the electrical plugs on the front of the filter head? Pull them out and look for leaks, maybe give the primer a pump or two.

wait a minute,,, isn't the stock fuel pump on the crd located in the fuel tank?

No fuel pump in the tank on these.

It's funny that this topic came up, just finished putting a universal inline fuel pump in today.

warp2diesel · **Posted:** Sat May 19, 2012 10:21 pm

Bean Counters deleted the Lift Pump, just so they could cut costs, which sucks.
A suck it out of the tank system can leak air into the system at any joint, coupling, hose clamp, ect.
Put a pump in the tank and the air leak from suction will no longer suck.
Just remember, if the fuel system sucks fuel out of the tank, it will suck air at any place it leaks.

papaindigo · **Posted:** Sun May 20, 2012 7:36 am

The CRD has the CP3 fuel pump mounted on the engine and driven by the timing belt. Decades if not generations of engines have done just fine with a fuel pump located on the block; often directly driven by a cam. This design is IMHO not a "bean counter" issue as the CRD runs a high pressure fuel injection system and an intake fuel pump simply cannot supply that type of pressure nor would I want it driving that pressure all the way from the tank to the injectors on the engine.

The bean counter issue is that they cheaped out on the fuel lines and used the same intake pump/fuel level assembly, minus the pump, and fuel lines as for the gasser KJ. The problem is in the lines which has at least 2 quick disconnect fittings that are designed to keep pressurized gasoline in not air out when diesel is being pulled thru the lines. FYI those old systems, mentioned above, typically had solid metal fuel lines with a short fuel hose connection at the tank (I've seen those go bad and suck air also or go bad enough that the hose walls collapsed when fuel was sucked thru the line).

Assuming you have not air leaks in the fuel filter head (1s gen head was prone to this) you can install a lift pump either in the engine bay, typically before the fuel filter head (be sure to put a small inline filer before the pump to protect it), or on a "frame" rail back near the fuel tank (there is wiring for doing so under the left side of the rear seat); or to replace the intake assembly with one that includes a pump; or to replace the quick disconnect fittings with fuel hose and clamps.

warp2diesel · **Posted:** Sun May 20, 2012 1:02 pm

In the Book published by Bosch on Diesel Fuel System Management they recommend the use of a lift pump. But to sell systems, their Salesmen/Saleswomen will promise anything the Bean Counter Wants to make the sale. That is why some go with the suck it out of the tank system.
The cam actuated lift pump mounted on the block or head was designed for gasoline engines that used carburetors where the fuel was dumped into a bowl and the bubbles came to the top and any air was sucked into the engine.
A diesel fuel system is hydraulic and air is not its' friend. When manufacturers used the cam driven diaphragm pump they would often put in an check valve air vent to bleed the air into the return line. Lines were robust and the connections were of the best quality to keep the air out of the system. Hose clamps on rubber hose was laughed at by Diesel Mechanics and Engineers of the time, because they knew they would fail and air would be sucked into the fuel system and the driver would be bleeding out the fuel system on the side of the road or walking. Been there done that. The quickie snap gasser pressure fittings used on the CRD would have made the Mechanics and Engineers of yesteryear split their guts laughing. Since our CRDs do not have a place to mount a cam driven pump, thought of the virtues of a diaphragm pump is a waste of effort to say the least.
As the operating pressure goes up the air can be more of a potential problem. The tiny bubbles that some who claim to be Engineers who act like they are gods above the laws of physics, ignore the side effects of fuel aeration which relates to ignition lag, higher operating temperatures, and loss of fuel economy, shorter injector life, shorter injection pump life, and on and on.
When you have Bean Counter management (Detroit) who are penny wise and mega buck foolish, threatening you with job termination, it clouds your views of what is best. When the Bean Counters screw up, they blame the Engineer and not them selves for being the fools they are. Fools who could not grasp the concept of Cost Benefit Analysis to increase the bottom line instead of short sighted Cost Cutting.
If you don't want the headaches go for the lift pump option.
Just keep in your mind, "AIR in the FUEL SYSTEM is EVIL".

lifter pump?

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