On going mileage problems after replacing cracked fuel line...

[Got Smoke?]

ok many of you know that I had to replace my metal fuel return line last week. Well the truck starts a lot better now, it didn't run any differently so there is no change there, but my mileage is STILL in the toliet! :{



280 miles and I'm on the WRONG side of 1/2 a tank.



Anybody care to throw out any ideas on what to look at? I hate to ask a mileage question cause I've seen so many pop up in the last week or two, but I really need input here.



I'm hoping its not fuel sending unit lying to me. I guess I will find out tomorrow I plan on either filling up tomorrow or Friday. I will see how many gallons it takes. Other than that please share some input. :{

 

[Gene Arnold]

Best advice I can give is ignore how long it takes to get to the wrong side of the gauge and rely on actual mathmatics to determine your true mileage. The first half of mine goes real fast, third quarter is real slow (almost never run lower than a quarter tank), but all in all I'm real satisfied with the fuel mileage (16-18 winter around the city, 4:11 gears)

 

[PUMPERDUDE]

Milage does sound a little low. . Usually the first 1/2 tank = 300 miles BUT as Gene said ,do the math when figuring mpgs... . If it is getting low milage ,checking the fuel pressure is a good start. This will tell you if your injector pump is getting fed right Good luck

 

[nfox]

Low mileage

I would check your fuel pressure to start with and then check your pump timing to make sure it is at 15. 5* or higher. Keep us informed on what you find out!!

 

[Got Smoke?]

Re: Low mileage

Originally posted by nfox

I would check your fuel pressure to start with and then check your pump timing to make sure it is at 15. 5* or higher. Keep us informed on what you find out!!

Been thinking of checking the fuel pressure.



What type of guage do I need? Can the same gauge that's used on a 24V work on my lift pump? I have a friend near by with a Briar Hopper 24V gauge.



Also timing was set to 16* probably two years ago now. 45K miles ago anyways if & when I get the time should I check it again? Same friend has the snap on timing kit I believe?



Still haven't filled up the truck yet to see if the fuel gauge is reading correctly, will do so first thing in the morning. Will also call up that friend and see when we can work on the truck if it comes to that.

 

[esommer2500]

My mileage goes down considerably in the winter, due to blended fuel and on-campus driving. It gets better when I can get out of town and drive, but nowhere near the 550 miles per tank that I see in the summer.



Eric

 

[Got Smoke?]

Originally posted by esommer2500

My mileage goes down considerably in the winter, due to blended fuel and on-campus driving. It gets better when I can get out of town and drive, but nowhere near the 550 miles per tank that I see in the summer.



Eric

I know that mileage goes down with winter blend fuel Eric, but it has never been THIS drastic of a change. :{

 

[wcjp]

Have you checked tire pressure or dragging brake's?

 

[Got Smoke?]

Originally posted by wcjp

Have you checked tire pressure or dragging brake's?

Tire pressure hasn't changed, and I'm sure the brakes aren't dragging. I filled up yesterday and the sending unit seems to be ok. Took 26. 5 gallons to fill up on just above 1/4 tank. Didn't some hand math uncorrected for my 33's and came up with 13. 25MPG usually get low 17's high 16's uncorrected. :{

 

[FreeBMW]

I go about 400-450 on a tank... ... . 400 and the light is on... ... 450 and I start to wonder when its going to run out..... I have seen 500 once or twice on a road trip (empty). Best of luck finding your issue!

 

[Got Smoke?]

Well we checked my lift pump today. Does 15psi @ idle, and 22 psi @ 3K RPM's sound good? Member WadePatton lent me his Briar Hopper gauge to test it with, and also said that it may be an overflow valve problem. Truck has 188. 5K miles on it for $25 I think I will replace the valve just to see if it helps.

 

[Cooker]

The pressures are low. An OF valve replacement is probably in order.

 

[Got Smoke?]

Originally posted by Cooker

The pressures are low. An OF valve replacement is probably in order.

You are correct sir... found this after a quick search.

Originally posted by bmoeller

Fuel Pressure: 18-24 psi at idle, 28-36 at 2000 rpm with no load.



http://dodgeram.org/tech/dsl/Facts/94specs.html

I'll be ordering my new overflow valve first thing Monday morning! Oo.

 

[DSiemens]

I've noticed that on my previous 12 valver that the mileage will decrease when the fuel filter starts to plug. Just a thought.

 

[Forrest]

Is this the round 'screen' filter that you replace from under the truck?

 

[Got Smoke?]

Originally posted by DSiemens

I've noticed that on my previous 12 valver that the mileage will decrease when the fuel filter starts to plug. Just a thought.

I usually change my fuel filter about every 3rd or 4th oil change, I try to at least. Unless I got some really bad fuel I doubt its clogged. Thanks for the thought though.

Originally posted by Forrest

Is this the round 'screen' filter that you replace from under the truck?

I've tried to get those kits from Cummins before and they always "say" they have them..... then can't find them on the shelf

 

[bmoeller]

Originally posted by Forrest

Is this the round 'screen' filter that you replace from under the truck?

http://www.dodgeram.org/tech/dsl/filter/pre-filt_clean.htm

 

[bmoeller]

Originally posted by Got Smoke?

I'll be ordering my new overflow valve first thing Monday morning! Oo.

See what price it is first at Cummins. At my local Cummins shop, they wanted $90. Peirs has it for much less, even including shipping.

 

[krs]

Hi Mark,



If you have the address of the source for a $25. OF valve you won't beat that anywhere. Piers was $65. about a month ago when I bought one.



Did you change the piece of fuel line that connects to the overflow valve - is that the one you mean? If not, have a good look at whether it might be leaking. Sometimes a slow leak that goes down behind the pump will be overlooked.



-ken

 

[Got Smoke?]

Originally posted by KRS

Hi Mark,



If you have the address of the source for a $25. OF valve you won't beat that anywhere. Piers was $65. about a month ago when I bought one.



Did you change the piece of fuel line that connects to the overflow valve - is that the one you mean? If not, have a good look at whether it might be leaking. Sometimes a slow leak that goes down behind the pump will be overlooked.



-ken

Ordering my OF valve tomorrow. The fuel line I had replaced was the rubber-to-metal (both replaced) that runs between the back of the cylinder head and the firewall. The one that commonly cracks and fails didn't... ..... the metal one did so I had both done!