DiamondSCattleCo
Well-known member
Faster horses said:
For anyone who wants to do their own checks, or have someone do it for you, from my experience, once the lift pump gets down to 7 or 8 PSI of fuel pressure at idle, you'll start seeing a hit to power and economy. Brand new is 15 PSI. Dodge uses some kind of garbage volume test now, but the volume they use is insufficent to ensure proper economy. When I owned my performance shop, we dyno tested a couple thousand Dodge's and saw up to 40 HP hits when the lift pump pressure dropped to 7 PSI at idle. At 6 PSI, you would have insufficient pressure to supply the injector pump at wide open throttle and you'd do damage to the injector pump.
If you find you are having alot of lift pump issues, the best fix is to buy a set of drilled out banjo bolts. There are 5 bolts in the system (2 lift, 2 fuel filter canister, 1 injector pump) and they are very restrictive. So restrictive that they drive the lift pump into a rapid cycle bypass mode (bypassing on and off quickly) and it would destroy the bypass valve. The banjos are available for around 40 bucks, and are very easy to change. We found it gave us another 100,000 klicks of pump life on stock trucks.
On the intercooler issue, rigging a test on your own is fairly simple. Take two pieces of 3" pipe and weld ends on them. Make sure they are air tight welds. On one of them, drill a hole and tap it to accept a Schrader valve (tire valve). Pull the intercooler boot off the air horn, and put the valve equipped end in the hose and clamp it down. Then pull the other hose off the turbocharger and put the other test adapter in that boot. Air the system up to 35 PSI, and use a bottle of soapy water to spray the intercooler down. Whereever you see bubbles, you have a leak. Also, I forgot to mention the clamps. Dodge used the cheapest clamps available, and they'll tend to back off over time. I should have mentioned this before, as its more common than the tank cracking. So spray down all the clamps and check for leaks. Spray all the boots down too, as its not unheard of for a boot to spring a leak, especially in salt heavy areas.
Faster horses said:
Interesting. You guys are one of the few. Up here in Canuckville, our diesel is of relatively poor quality to US diesel, so we saw even greater hits. My 2001, stock, used to run about 18 mpg. My 2003 (introduction of the common rail) dropped this average to 16 and my 2005 is down to around 14 mpg. The 2001, with the addition of a timing box and a good set of balanced injectors, would get upwards of 22 mpg. Using US fuel, and correcting the gallons back to Imperial, I'd get 24 with ease.
I'm actually selling my 2005 and stepping back into a 1994 - 2002 truck. While I like the handling of the 2003+ trucks, the seats on the 1997 - 2002 trucks were far more comfortable (in so far as premium leather ones were concerned anyway), the 16" tires much cheaper to replace than 17s, and I still have a few performance parts for the older trucks kicking around that I never sold when I shut down.
Rod