What are y'alls opinions on installing a fuel cooler and/or lift pump. Are either necessary with your ECO tune? Without it? If it helps, my CRD is 99% a DD vehicle.

I have yet to experience air in the fuel problems and am under the impression that the factory injectors are intended to work without a lift pump. The problems I've heard about seem to arise only if you have a weakened vacuum seal or "O" ring. Your thoughts?

Thanks.

A fuel cooler is not necessary on the KJ CRD. The temps rarely get over 130 F and only in low fuel level situations. Towing a 5000lb trailer with low fuel one can see up to 175 F with less than two gallons remaining in the tank...ie. with low fuel light on. Not something most people would ever consider doing. A fuel limitation starts around 160 F and progesses up to 195 F at which time the engine will only idle. We have never seen temps near this high.

A fuel cooler can be a drawback if living in cold climates, there is more potential for line freeze with a cooler and the fuel heater on the vehicle does nothing for frozen fuel lines near the tank.

Damn this is a great reference!~ Keep up the good work GDE!~

Thanks, what about the lift pump?

Fyi, I just got a hand-calculated mpg of 25.4 in town on your tune! This was with 117 miles of in town (80% 35-45mph) driving pre-tune and after having the CRD sit for 10 weeks with a tank of B5 festering away - plus three trips to a mechanic for various fuel changes and who knows how much idling around.

Approximating a pre-tune mpg of ca. 19-20, this means I got around 27-28 mpg around town with your Eco tune on a tank of old (and not high quality to begin with) bio!

Thanks so freaking much for all you guys do!

If the vehicle is functioning correctly there is no need for a lift pump. Our vehicles have been updated with the new fuel filter head assembly that fixes the fuel heater circuit wiring issue so the system will not pull air through the filter unit. It is important to change the fuel filter as recommended in the service manual to prevent a large pressure drop across the filter unit.

If one is having issues with hard starting, or engine shut-off due to fuel starvation there is a leak in the fuel system somewhere. We would recommend root causing the leak, but a lift pump would also address the issue. Our concern with the lift pump is having positive pressure on a fuel system that could possibly have a leak, there is a possibility that the pump could push fuel out the leak path onto the ground or in the engine compartment...this could lead to a potential fire hazard. The lift pump should be very low pressure, 2-4 psi would be plenty.

The system was designed not to need the lift pump, but the system also has potential for leaks so this is catch 22 and requires preventative maintenance.

May I ask when the new assembly you refer to came out, and should it have been fitted as a matter of course by a dealer during servicing?

GDE,

Thanks, that's exactly what I figured. A lift pump doesn't solve air in the fuel issues, it just may make them less readily apparent. The solution is to fix the leak, not pump the fuel harder.

Thanks!

I am glad I read this, I was beginning to believe I would need to add a lift pump, but I will keep the fuel system stock, regular filter changes, and trouble shoot when I get the P0093 DTC.

Lancer wrote:May I ask when the new assembly you refer to came out, and should it have been fitted as a matter of course by a dealer during servicing?

I realize this is an ancient thread, but I too would like to know what the "new" (now old, obviously) assembly is.

The original assembly had thin power wires going to the fuel heater element. The wires were heating up and melting a small void around them letting air in. You can tell if you have a stock fuel filter/water separator assy by looking closely where the power wires come in. If you see signs of burning (brown coloration), congratulations, you have the stock assy. The upgraded assy has heavier duty wires. It's a pretty easy install.