Oops, sorry, I thought you had a C-6

 

Your truck came with electric pumps? Mine has the the old mechanical pump.

Mine's an 86 F250 460/C6, pretty much the same you've got except the year.

Were electric pumps an option?

Scott

 

One in each tank and an inertia switch under the dash on the firewall. One of the guys here at the dealership mentioned that there may be another one underneath also, kind of a booster?

Interesting that your '86 should be mechanical ....

Roger




63,000 original miles

 

what is the top speed in 1st gear?

 

I never take it over 5 mph. I checked the door sticker again, the AXLE code is C5, the transmission code is "F"


Greg

 

Very interesting indeed... I even bought a Carter street/strip pump
for the truck but haven't put it on yet... 9PSI from the pump and I
will run a regulator as well... seems so far that the stock pump is
doing okay... still need to bring the CFM down from 750 to 600 tho.

Scott

 

I think C5 is limited slip 4.10, I believe it is the Sterling axle..

this link.. it has pics. http://www.motivegear.com/tech_info/...nny_guide.html

according to chilton's, code F is BW T-18. [just looked].

 

FWIW - I found elsewhere here on this forum something that sounded just like this as I was having the same problem in my 302 XLT. The thread said that there was a fuel filter designed to last the life of the truck hidden by a cross member between the tank and the "normal" fuel filter that was often clogged and many found it was clogged.

Well I checked my truck and I did have an extra filter but mine was in the bottom of the tank switch. Sure enough it was black and I couldn't even blow through it without a great deal of effort. $3 from the local AutoZone and my power shot up dramatically!!!

My filter was as I said in the bottom of my tank switch and you will need a strap wrench to get the bottom off. The filter is about 3" in diameter. Pretty easy to do though I had a hard time getting the large rubber ring gasket to stay in place to seal it back up when screwing the bottom back on.

Before I had a hard time climbing hills but after changing this filter out, I drove from Palmdale California, through Nevada on the I15 with those big hills and through Utah to South Dakota and was charging ahead at 85 most of the way.

It won't solve the MPG problem but thought I should mention it since your problem sounded more like a filter.

Good Luck,

Lee

86 F-150 XLT
302 EFI, JBA Headers, 3" Exhaust, w Magnaflow Cat and Muffler Mod

 

Tanks for the reply (pun intended)!

If I understand your post correctly... I think your describing the "windsock"
filter that's on the sending unit itself.

Is your truck FI with an electric pump? Mine's carbed with a mechanical
pump and dual tanks... I'll take a look anyway and see what I can find,
if it's the windsocks in the tank, I can always run a pressure test.

Thanks!
Scott

 

Bremen242,

Thanks for all of your information!

Regards,

Greg

 

No, it is in the bottom of the Tank Switch that makes the electrical swap between tanks. It should be on the inside of the frame just behind the Fuel Filter, maybe 2 feet or so. Mine has a round bottom on it and I had to put a strap wrench on it to unscrew the base.

Yes, I I have EFI on my 86 truck.

Good Luck,

Lee

 

using the gauge to judge milage is NOT!!!! accurate enough to base any sort of judgement on it.....

fill your tanks and note the odometer reading, burn a tank of gas, fill the tank and note the amount gas you put in and the odometer reading......

also i find that too many people use one particular driving instance as a judgement on the milage there vehicle gets......

iv kept track of every drop of fuel my 85 f150 4x4 4 speed on propane has used since i owned it and i and i have the records the previous owner kept track of since day one!! thats 413,000 km ago

there are so many factors, my particular truck gets 11 mpg in the city or winter time and about 12 on the highway or summer time, iv scene it get as low as 9 and as high as 14, i find temperature and type of driving plays a huge!!! role in it..... say i was one of those people who judged my milage on one tank of fuel on a highway trip in the summer getting 14 mpg, or say i checked it one time after a tank of fuel burned in the winter driving in the city getting 9 mpg...... see the difference and misconceptions that can happen.......

I dont think its possible to get 3.5 mpg out of your pickup..... 8 or 10 maybe ..... i say keep track for several months and youll get a better judgement for it.....

-gbm-

 

when my choke was frozen shut, it was pretty close to 5-6mpg, on a 300-6.

 

1989 F350 SC long bed dually, 460 EFI, C6, 4.10, ~26'flatbed gooseneck trailer with tandem dual wheel axles empty .... headed to Iowa - 6.4 mpg, coming back with a light, low wind restriction load - 4.6 mpg. We added a 55 gallon L-tank in the bed rigged to fill the main fuel tank on the roll when we hauled AC Gleaner combines with three row cornheads (lots of weight and wind drag). Never had the guts to measure mileage then just glad I didn't have to pay for it!

 

ok i retract my statement about it being impossible to get 3.5 mpg but my main point was figure out the mileage correctly then go from there.....



-gbm-