terrible fuel mileage
11-11-2006, 02:35 PM
#17
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http://dodgeram.org/tech/dsl/filter/pre-filt_clean.htm
Not a bad idea to tighten all 8 of the boost boot clamps to 10 ft/lbs. I usually check them on my trucks every service.
11-13-2006, 12:51 AM
#18
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no boost leaks i check truck over pretty well about once a month look for things like loose clamps boots rubing anything or any new leaks of any kind as a auto repair tech i have learned keeping a close eye onthings can prevent many costly repairs in the future
11-13-2006, 12:54 AM
#19
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ordered a new overflow vavle from tst the other day will be here next week hope i fixes teh problem couldn't resist it had to also buy a new goodie i purchased the afc spring kit also
11-16-2006, 01:09 PM
#20
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just checked with the dealer for overflow valve. they wanted $159 for the overflow valve and $35 for pre-filter screen.
cummins wanted $6 for overflow valve (check valve)
still shocked at the price differences...
cummins wanted $6 for overflow valve (check valve)
still shocked at the price differences...
Thanks to infidel for the pic of the overflow valve.
You may have to grind the notch a bit to get the old one out. Pretty simple job if you don't lose the washers. Takes about 5 minutes. Don't bend the line to get it out though, makes it terrible hard to get lined up again.
The prefilter is located inside the fuel preheater assembly. Look to the immediate left of the lift pump and you have the assembly. Takes a 17MM?? wrench to open it up (from the bottom) and the screen is inside.
You may have to grind the notch a bit to get the old one out. Pretty simple job if you don't lose the washers. Takes about 5 minutes. Don't bend the line to get it out though, makes it terrible hard to get lined up again.
The prefilter is located inside the fuel preheater assembly. Look to the immediate left of the lift pump and you have the assembly. Takes a 17MM?? wrench to open it up (from the bottom) and the screen is inside.
11-16-2006, 06:36 PM
#21
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mmmmm, I think you're saying cummins wanted $6 for the prefilter repair kit. Not for the overflow valve. If so, let me know which cummins it is. Cause here in Portland they want $90 something for the overflow valve. All the dealer does is buy stuff from cummins and then double or triple it. Dealerships are usually good for nothing.
11-16-2006, 09:42 PM
#22
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nope cummins quoted $6 for what they call a check value. was described in correct locatioin.
so we'll see if $6 is correct tomorrow. still don't understand why a overflow valve would affect mileage?
so we'll see if $6 is correct tomorrow. still don't understand why a overflow valve would affect mileage?
11-19-2006, 08:39 PM
#23
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So did the overflow valve end up really being $6 bucks? And did it solve your problem? I am having similar issues, so I'm interested. And if you got an overflow valve for 6 bucks I think everyone is interested.
11-19-2006, 10:06 PM
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11-20-2006, 05:54 AM
#25
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visited the cummins dealer friday.
yep they flat goofed quoting me the $6 price. correct price is $94 from Cummins. since they goofed on original price and couldn't sell for $6. they sold me the overflow valve for $59.
found out from cummins tech that overflow value does more than dump fuel upon pressure too high. overflow valve actually regulates fuel pressures.
they test pressure by isolating line. fuel pressure should read 23lbs or better if overflow valve is working properly.
tech recommended changing to new pre-filter basket instead of cleaning.
yep they flat goofed quoting me the $6 price. correct price is $94 from Cummins. since they goofed on original price and couldn't sell for $6. they sold me the overflow valve for $59.
found out from cummins tech that overflow value does more than dump fuel upon pressure too high. overflow valve actually regulates fuel pressures.
they test pressure by isolating line. fuel pressure should read 23lbs or better if overflow valve is working properly.
tech recommended changing to new pre-filter basket instead of cleaning.
11-20-2006, 11:32 AM
#26
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So you think you'd notice a drop in mpg's if the overflow valve was no good? I don't want to dish out a $100 for a new overflow valve and then realize it made no difference. I feel like there's something wrong with my fuel economy as well. Can't seem to get better than 15-16 on the highway going 60-65 empty. That was before all my mods and driving it very conservatively.
11-20-2006, 12:57 PM
#27
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You may want to just remove the overflow valve; carefully pull out the spring and steel ball. Stretch the spring to slightly longer than 1/2". Then reassemble and tighten back up. You can do this a few times until the spring gets "tired" and won't keep the stretch for very long.
As for the clicking sound mentioned earlier, you should price a new lift pump to install while you're down there replacing the pre-heater filter screen. They usually let go at around 150K - 200K miles. Clicking is the most obvious symptom; but low fuel pressure to the P7100 is the end result. Cummins will be less $$$ than Dodge dealer.
As for the clicking sound mentioned earlier, you should price a new lift pump to install while you're down there replacing the pre-heater filter screen. They usually let go at around 150K - 200K miles. Clicking is the most obvious symptom; but low fuel pressure to the P7100 is the end result. Cummins will be less $$$ than Dodge dealer.
11-21-2006, 04:54 AM
#30
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You can replace when the fuel pressure drops or there is a member on this board that recommends replacement every 75,000 miles. You can also diagnose an overflow valve problem by pinching off the return line to see if the problem clears up.