I have a 2001 3500 dually 4x4 quad cab long bed, stock tire size, nv4500 5 speed with 3:55 gears. What is the average fuel milage expected from these trucks? The only "mods" done that I know of are a FASS ddrp pump in factory location and the exhaust has been replaced but nothing crazy. I measured the tailpipe it's 4" but have not measured the rest under the truck yet. So to my knowledge it's pretty bone stock with 141k on the clock.

 Last I checked I was at about 15mpg. Mainly to and from work, about a 20 Mile drive, about 5 of that is considered city the rest is state route 60mph or highway about 65mph.

 Just curious if I'm around the norm for what I have. Thanks.

Stock form they did about 16 to 17 MPG. I had kept fuel logs from back at 20k miles.

 

Tuner and injectors are the most important things. No need for exhaust or intake stuff. You won't be flowing much anyways. Quadzilla tuner will combat the low timing the ECM provides. Injectors are typically wore out at 100k miles. Fresh injectors with a bump in pop pressure helps for bigger injectors like what I run. But typically you need your boost near zero and EGT's below 600*F. Timing does that by allowing injection event earlier and more power made on the piston not blown out the exhaust.

 I was just reading your write up on low pop pressure and how to recognize it. I have an obdII scanner with live data. I will plug it in next time I drive it and check the engine load at idle. Mine tends to idle a bit above 800 rpm so I am now wondering if it is due for injectors. If so, would it be better to go with a slightly bigger injector? Like a 50hp or 75hp? 

My truck had some 75hp when I got it so I couldn't tell you stock. Best i got was 19 out of that set up. I've been getting 16.5 or so combined hwy/city lately and in warmer weather at same driving habits I'll get close to 18. If I want to get over 20 I need to drive around 60mph, same goes for my vw tdi, it gets best mpg at 60mph, I've hit 52mpg last summer. Now it's been low 40s. Still beats 16 that truck gets and I get to drive a diesel 

Mine got around 17.5 cruising interstate 70 or so when it was new. RV275's and the edge comp got me to 19.5  cruising 75 on the interstate.

@Doubletrouble your current mpg’s aren’t that far off, considering its winter time, are  you running winter blend diesel? That will reduce your mileage by 2 mpg or so 

 Yes it is winter blend diesel around here (northwest Ohio) so I imagine it would improve some in the summer.

 I also snapped a couple pics of the live data scanner while the truck was idling. I've attached them for y'all to look at. I'm new to diesel pick ups so let me know if you think something might be off.

 

 And yes, the abs light is on. It flashes constantly. Not sure why, my scanner won't link to the abs system. Brake light is only on when parking brake is set.

What sticks out to me is a 0.0 for engine load.  It shouldn't be 0, there should be some reading at idle .  Also your throttle position is reading 9.8%.  If this is at idle then your throttle position should be 0%

Not sure what those readings mean.  Could be just your reader or could be real issues (injectors, TPS, or ?).  Hopefully someone more educated on these things will chime in.

13 minutes ago, hdpwipmonkey said:

What sticks out to me is a 0.0 for engine load.  It shouldn't be 0, there should be some reading at idle .  Also your throttle position is reading 9.8%.  If this is at idle then your throttle position should be 0%

Not sure what those readings mean.  Could be just your reader or could be real issues (injectors, TPS, or ?).  Hopefully someone more educated on these things will chime in.

 

You are 100% right, it shouldn't be zero. However, some trucks don't report an accurate engine load on the communication bus. Quadzilla for example, for this reason, I believe simply reports 0-100% fuel command as load. So that zero might not be accurate.

17 hours ago, Doubletrouble said:

And yes, the abs light is on. It flashes constantly. Not sure why, my scanner won't link to the abs system.

 

98.5 to 2002 requires the DRBIII tool to read the code. I've got a expensive Innova Scanner and it skips my truck. Typically the ABS light is a bad tone ring in the front axles or bad sensor in the front axles. If it was rear axle you would of mention speedometer not working. 

 The speedometer works just fine. The light is an annoyance more than anything. Once it warms up I will address it. A buddy has an expensive snap-on scanner that does abs. I'll see if his will read the codes. If not I can just replace the sensors and see if that fixes it or take it to a dealer for scanning. Just don't like going to a dealer for much of anything. Very expensive just to plug into it.

On 2/9/2020 at 8:31 AM, Mopar1973Man said:

f it was rear axle you would of mention speedometer not working. 

I had an ABS light come me and go. In summer it would come on after 10 minutes of driving and stay rest of the day, in winter it would take a lot longer before it came on and lots of times it would shut off then it could come back on or stay off, never same. 

After front sensors then hub assemblies it was still acting up, then I had abs module rebuilt, same thing, then changed rear sensor again, changed it once when problem first started, and no more abs light. Idk wth is with these trucks and random wire/sensor issues. 

I had the ABS/brake on a couple years back with new front bearings on. I replace the rear sensor and the light stayed on. Then about 2 months later it went off and has not been on since. The ABS works as it should now, though it did not while the lights were on. I have no idea as to why it took so long and never lost the speedo during the entire episode.

I think a lot of these jobber sensors may not have the correct gap between the sensor and tone wheel. Also explains why it changes with temperature, as things expand and contract. I experienced this with my 1999 Jeep Grand Cherokee with a 4.7L V8. Lost a crank sensor. Replaced the sensor with a jobber from a local auto parts chain. Would run for a few minutes until things heated up, and then it would die. I ended up replacing the PCM and wasted hours troubleshooting. Finally I went and bought a sensor from the dealer, which ended up being cheaper than the jobber, and the problem was solved.

 

My point is if you replace a sensor, and your problem doesn't 100% go away, and nothing else makes sense, don't be afraid to try another sensor. Quality of manufacturing in every industry is suffering as costs are cut to appease shareholder dividends. Auto parts are definitely not immune to it. It's a worldwide disease. 

 

Sorry for the negative twist lol. Trust nothing!

Edited February 11, 20205 yr by kzimmer
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Your probably about right on mpg with a dually. You may be able to raise it up a little bit a dually just won’t get the mpg a single wheel truck will.

 I was just curious if she was in the average range for what it is.

 As far as the abs sensors, I had a Chevy suburban that the abs light came on. Had to remover the sensor and clean the mating surface. It would get a bit of rust build up under there and increase the gap between the tone wheel and the p/u.

 I haven't checked for this on the Dodge yet. Honestly, it's been cold and I haven't felt like it. Lol

46 minutes ago, Doubletrouble said:

 I haven't checked for this on the Dodge yet. Honestly, it's been cold and I haven't felt like it. Lol

 

I hear that... Going down to -24°C tonight. I discovered a small fuel leak on my fuel pressure sensor after work. Work on it in the cold, or turn off the needle valve? ... Needle valve.

Needle valve is a wonderful thing!

4 hours ago, Mopar1973Man said:

Needle valve is a wonderful thing!

 

Yeah I was pretty thankful that I could stop the leak easily.

 

This is off topic (sorry @Doubletrouble), but I'm having a really hard time getting my quadzilla threaded fuel pressure sensor to seal. I've been using yellow Teflon tape. Should I clean that stuff off and try that white liquid pipe dope?

 I don't think I would try the liquid stuff. You certainly don't want any of that making its way into the fuel line. That would cause a lot of havock. 

 Doesn't loctite make a thread sealer as well? Though I read about it somewhere while looking for something else.

I do a lot of hydraulics and pneumatics at work.  We use the loctite 545.  There are others like vibra tite and such that have a similar product.

 

We use it especially in the pneumatics, the ports are so small  just a smidgen of tape or basically anything can cause a problem in the logic.    In the hydraulic systems and booboo extra just becomes miscible in the fluid and goes away. 

 

HTH

 

Hag