Horrible fuel mileage

galute · #1 (**permalink**) 10-28-2009, 09:50 PM

My truck is getting horrible fuel mileage. As in 8 to 10 depending on how I drive it. I think the timing may be off. It does not start as good as I think it should but it runs great. The line up marks on the fuel pump are way off. The pump is turned to the pass side about 1/2 inch between the marks on the pump and cover. The pump has most likely been swapped at some point but should the marks be that far apart? I don't have the tools to check the timing and can't find anyone near here who does. Is there a way to set the timing without a ferret or whatever it is called?

87crewdually · #2 (**permalink**) 10-28-2009, 10:30 PM

1/2" is pretty extreme. Usually you only need to move it 1/16 or sometimes less towards the pass side. I'd consider backing it back towards the driverside a little at a time with test drives in between to see if there is improvement.

redbrutis · #3 (**permalink**) 10-28-2009, 10:40 PM

The lines don't necessarily have to line up and often don't. They are ther for the installation of the pump and often the pump is adjusted from there. 1/16" is probably about the norm. If it's too far advanced the motor will sound like it wants to blow up. (I've had experience

). Interestingly though, I got my best milage with "over"-advanced timing.

87crewdually · #4 (**permalink**) 10-28-2009, 10:43 PM

Quote:

Originally Posted by redbrutis

The lines don't necessarily have to line up and often don't. They are ther for the installation of the pump and often the pump is adjusted from there. 1/16" is probably about the norm. If it's too far advanced the motor will sound like it wants to blow up. (I've had experience

). Interestingly though, I got my best milage with "over"-advanced timing.

Read his post. He stated 1/2" between the marks. Thats HUGE.

galute · #5 (**permalink**) 10-28-2009, 10:54 PM

Just wondering. Are all pumps indexed the same from the factory or does someone mark the cover and pump after they are installed? If they are marked afterwards that could explain why the marks are so far apart if the pump came from a different motor.

joe f350 · #6 (**permalink**) 10-28-2009, 11:00 PM

how old are ur flitter

87crewdually · #7 (**permalink**) 10-28-2009, 11:07 PM

The pump itself is marked with the scribe calibrated to be installed on an engine straight up to get it running. From that point it should be timed with either the proper equipment (which alot of shops rarely have anymore) or a good "ear". Some guys will bring the timing mark towards the passenger side 1/32" at a time until at a cold start the engine will have a "power stroke" rattle and warmed up the rattle goes away. You need to know what to listen for to use this method.

galute · #8 (**permalink**) 10-28-2009, 11:31 PM

Quote:

Originally Posted by 87crewdually

The pump itself is marked with the scribe calibrated to be installed on an engine straight up to get it running. From that point it should be timed with either the proper equipment (which alot of shops rarely have anymore) or a good "ear". Some guys will bring the timing mark towards the passenger side 1/32" at a time until at a cold start the engine will have a "power stroke" rattle and warmed up the rattle goes away. You need to know what to listen for to use this method.

So, if I understand you correctly about the marks my timing is way off or the pump is installed incorrectly. I will try harder to find someone with the proper tools to time it. Thanks for the info.

galute · #9 (**permalink**) 10-28-2009, 11:33 PM

Quote:

Originally Posted by joe f350

how old are ur flitter

The flitter's were all changed about 2k miles ago when I change oil. LOL