After not towing for five years with my 92 D250 I bought another fifthwhell which weighs around 11,000 pounds. Before leaving on a trip I turned down my fuel about 2 turns and tightened up my star wheel 2 turns along with setting the timng back to the original setting in an attempt to make the engine last longer, well long story short my fuel mileage was bad, only getting 9.7 mpg. So while I was on the trip I set the timing back up, well the mileage went back to 12 mpg but now when I pull a hill and the boost gets over 15 lbs the engine starts missing almost like a gas engine with a bad plug wire. Could I not be getting enough fuel for the bigger injectors? My injectors were called Power Wagons back then but I don't know the specs. They have always performed well without too much smoke. I just got home this evening so I haven't had time yet to do any troubleshooting. The fiel filter only has about 5,000 miles on it. Any ideas?

 

No one huh? Well I guess im on my own troubleshooting this one.

 

Give it some time, Sundays and mondays can be a bit slow, someone will chime in, I promise ...Mark

 

What sort of lift pump do you have? It sure sounds like you're fuel starving. I assume you've changed your fuel filter again. sometimes you could get some dirty fuel and plugged it up.

 

If your still able to achieve the same boost number when this is going on I can't see it being short on fuel. A miss like that is not easy to describe or explain in a post on a forum. I would just take a look at your fss and its wiring to make sure you don't readily see something that could cause an intermittent loss of power their. They can sometimes act like an engine miss.

 

For me, this is not quantitatively descriptive enough to help diagnose the problem.

What does the Manifold pressure gauge do? The pyro? Smoke? Fuel pressure? Is the truck shuddering with the "miss"?

 

I don't have a fuel pressure gauge, the lift pump is just a standard pump. The boost gauge fluctuates a little as it is missing, the pyro holds steady. The truck is not shuddering but just a jerk kind of like something pulling it back and then letting go. It starts when the boost gets to about 15. No problem on level ground but seems to have a lack of power when I floor it from about 60 mph. The smoke is still about the same as it was before. My boost tops out at about 25, it was over 30 before I turned the fuel down. It stormed all day today so I didn't get to work on it, I am going to change the filter tomorrow and try turning the fuel back up a turn to see what happens. Everything else is back to the way it was before I set the timing back.

 

As mentioned above, Check the connection of the FSS. It really could be that simple, that the connection is a bit iffy and it loses contact when you are pulling hard...Mark

 

I will for sure. Probably will put a screw on connector because it did come loose once and died in the middle of the road.

 

I meant the color of the smoke, if any, when the problem occurs. If you start to smoke bluish grey, then I would guess a clogged fuel filter or other fuel supply problem.

I also forgot to ask, is it rpm dependent?

These are only valuable questions if it is not a flaky FSS.

 

Let me guess. Your running some type of waste gated turbo. Either way, it sounds like turbo surge to me. Engine can’t digest = bad flow.

 

Rlyons, just a friendly tip on putting in a ring terminal and screwing the terminal down with the factory nut- I don’t know how large your hands/ fingers are, but it is tight getting to that area to complete that task. Not to mention awkward, and having to turn into a contortionist. The hardest part will be trying to thread that nut back on, without accidentally dropping it deep into the engine bay.

My advice, is to go to your local sporting goods store like a Big5, and go to the baseball section. In that area they carry a stick of rosin, made to add sticky grip to the bat handles. I originally purchased that to place it on the bottom of my scope ring mounts on my hard hitting rifles, to avoid scope movement.

I slapped a tiny bugger of that stuff on my index finger, and stuck that nut on there. Laid the nut right on the FSS stem, a twist of the index finger, and the nut threaded on enough to hold. From there, the index finger and the thumb threaded it on all the way down super easy. Wrench to lock things down.

Since then, that’s how I install tiny nuts and bolts in tight spaces anymore.

 

I have learned something new! Thanks.

 

Good tip bigragu

 

My opinion only, but if your going to go thru the trouble of soldering a ring terminal on, do cut that back side bracket, the one directly behind and attached to the VE pump. The excess is about 3” long, past the last set of bolts that mount the bracket to the pump. Hack it off, so getting a tool in there to remove the FSS in case a replacement is needed, is much easier.

Also, tie in a switch somewhere in between that electrical wire that your going to put the eyelet on, and mount the switch inside your cab somewhere. Makes a good anti- theft device as the truck will not start with no power to the FSS. No way, no how, lol!