Bike = Suzuki Boulevard C50 .

Awesome ride today. Can't wait to do it again tomorrow. And it gets like 45mpg!

 

I was driving through Amarillo, Texas and my speedo read 72 MPH and I was pulled over for 79 MPH and given a warning. I am running 37s and 4.30 gears, which I swapped out my 3.73s. I thought for sure my speedo would balance out. I was wrong.

 

ok im having the same exact problem 2002 f-350 4x4 crew cab dually 4.10 gear 130000 miles
mods, gauges, ats turbo, bypass fuel reg (smoother then a str.6 gas), HX crossover (wow), injectors o-rings, and cps done at 115,000, ais air filter. up untill 8,000 miles ago i was getting between 14-15 then after i did the turbo and i was getting 15-16 and now alll of a sudden im getting 12-13 all the time if im lucky and i have checked everything and its drving me nuts idle is smootha as silk have changed everything.
im thinking it has to be my new tires or the trans i upgraded from goodyear rt/s to silent armor this time and at the same time i had the trans and transfer case flushed aand then my mileage dropped and i did all the work since im a part time mechanic so i know the right flluids were put in so my theory is either the more aggresve tires are to blame or my trans is going since this is a truck that pulls my 18000lb horse trailer every week for at least 200 miles since the day i bought if it is time for BTS thank god. sorry this is long but i need advice im no diesel expert but at 72mph im reving at 2200revs which is ideltecal to my friends exact same truck without the mods granted his is twice as loud as mine hes getting better milage but he only has 40000 miles and stock tires help???????????????

 

2 things still come to mind. Use a GPS to check your truck speedometer and odometer. I didn't believe mine was off until I checked. My stock tires were actually making my speedometer show 5% faster than gps. When I went tho 285s actual speed and shown speed were very close. Now with 315s I am off about 9-10%. Not knowing this will affect calculations. And as already stated never ever trust the lie-o-meter on the overhead console. I wish it were right. I would be getting 24.8mpg. I only use it when my Chevy buddies ride with me.

 

Back to the original topic: Is perhaps your fuel filter drain leaking out while you are driving? That would be verified by a wet outlet for the drain next to the right side exhaust manifold.

 

If the fuel filter drain does leak, what is the fix for that?

 

there's an O ring kit on the web page part way down:
http://www.blackclouddiesel.com/Ford/codepigtails.htm

 

Thanks Nut...As a rookie at this diesel stuff, it's comforting to know how to find repair items like this when I need them.

 

have you cheched the fuel pressure in the head with the truck under load? My truck was acting simililar to yours,almost stalling on intial start up, running rough, and had no power. no black or white smoke, or any other symptoms. my fuel milage dropped from 21mpg to 17 mpg. when i checked the pressure, at idle it was 55 psi, but when under load, it dropped to 35. the pressure should not drop at all under load

 

That's exactly what mine was doing! And I fixed it by replacing the fuel pump.
https://www.ford-trucks.com/forums/s...d.php?t=440448

 

How about a clogged inlet screen?

 

That's exactly what the problem was in my pump. Clogged screen. I could have gotten away with cleaning it out and reinstalling it, but by then I was on a roll and the new pump was going in!

 

Can't argue with that Kwik! There's your pre pump pump for pushing fuel thru
i nice MG inline fuel filter.
Nut

 

Is there a good way to check fuel pressure under load? Easy to check at idle, but what is the best way under load?

 

An FP guage in the cab...about $125 with the isolator OR... on a chasis dyno??
Nut