Injector questions/fuel mileage drop

[blacksmoke94]

I've had a noticeable drop in fuel mileage recently and am leaning towards it being worn injectors. Was getting 15/17 on average and now it's more like 13/14. Air filter recently cleaned and fuel filter recently replaced. Tires are all aired up. No change in smoke or power but engine seems to be running a warmer than normal and the outdoor temps have cooled down. I can hear the fan clutch engaging/disengaging as it always has. The IP has about 110k on it and I hate to say it but I think the injectors are original and have 271k on the engine. I plan on doing a complete rebuild next spring and make many upgrades to it, one of which is getting a Bull Moose pump and Mark II injectors. With my pump still seemingly working fine and turned up 3 flats, would it drive a set of the Mark II injectors? I can't afford the pump and the injectors at the moment but can do the injectors. I hate to buy a set of stock injectors and then replace them next spring. Makes no sense. Is there something else that could explain the drop in fuel mileage?

 

[icanfixall]

Its probably the injectors failing rapidly but it could be the pump timing is changing too. As the pumps wear out the timing changes more towards a retarded timing. You might try this. Make a center punch mark in the pump to housing joint line. Make sure its in the line between the pump and the housing it bolted to. Now move the pump towards the passenger side fender. Thats advancing it. Those bottom nuts are tuff to reach and when the pump is loose it may slip backwards because of the tension the hard lines make on the pump. This is a really bad way to time the pumps but its all we have. You can loosen the easy to reach top lines at the back of the pump to ease the turning. Just remember to tighten them up when done. Move the pump about the distance of the mark made by the center punch. It will look like 2 half circles now on that line. If the engine runs better leave it. If its worse move it back till the half circles line up.

 

[blacksmoke94]

I just had the timing checked and it was at 9*. I want to back it off to about 7 1/2 to 8 to get more low end power. On an average center punch mark, let's say 1/16" in dia., then moving the pump until the corners of the half circles line up, what would that amount be degree wise? All that aside, would my pump drive the Mark II injectors?

 

[Ugly Moosling]

You would be fine putting the Moose Misters in now. The combo will obviously work better once you install the Moose pump but it'll still work with your pump.

 

[blacksmoke94]

That sounds like the next step then. I've never changed injectors in a system like this so I guess it's time to get to learning. It's gonna suck with my bad back but can't afford to pay someone to do it. Like I said, I believe these injectors are from the factory which would be amazing to get that many miles out of them??

 

[crashnzuk]

Did you get different fuel, maybe winter blend? I assume they do that in Reno?
Travis..

 

[blacksmoke94]

They do run a winter blend here in Reno but it's never affected my mpg's before. I also put in at least the recommended amount of Diesel Kleen in just about every fill up. I had the same thought but like I said, this is all new. We just got back from a long road trip and even loaded with over a thousand pounds of payload and many steep grades, I averaged 15/16 and now it's all I can do to squeeze out 13/14 running empty and driving like an old man with no where to go and all day to get there (no offense)