I was reading another post and came across another probable issue with my truck. My '89 f250's motor (351w) sounds like a "quiet diesel" so to say. I have checked for exhaust leaks, none found. The fan clutch is seeming to be engaging/disengaging the way its supposed to be. Is this a common sound for these trucks? I have a glasspack exhaust on the truck and ALWAYS hear the motor over the exhaust at both high and low RPMs.

Also, im still having the issue with the gas mileage on this truck. Its getting 7 to 8 mpg with a mix of town/highway miles(only about 40 miles on highway). I took my 33x12.50x16.5 tires off to see if this would get any better, and low and behold, it didn't. Any suggestions?

And i have heard the PLatnium plugs aren't the best for this truck. I was told to go back to the motocraft coppers. any input on all this ?'s will be appreciated.

Vehicle Specs:
1989 F250 w/ 351w
4.10 gears
fuel injected
K&N FIPK intake
autolite plugs and wires (Platniums)
C6 tranny
All fluids are full synthetic
31,000 org miles
245/75/16 BF goodrich all terrains

 

sorry i cant help about your prob... maybe chek the EGR for leaks..?

but highway 40 mpg?????

 

Have you performed a compression/leak down test?

I think he was saying he only travelled 40 miles on the highway, not that he was getting 40mpg.

 

I ran the codes on the truck and the only code it gave me was a 33. Which is "EGR valve opening not detected". So maybe its stuck closed, or faulty? How would i go about replacing this?

 

I ran the codes on the truck and the only code it gave me was a 33. Which is "EGR valve opening not detected". So maybe its stuck closed, or faulty? How would i go about replacing this?

 

I can't remember but does you truck have dual tanks and is is pumping fuel from 1 tank to the other?

Unfortunately with the gearing and tranny you have(C6), you won't get anything resembling good milage at speeds over 50mph, that's life without overdrive.

 

How about stupid stuff like a vaccumn test and fuel fliter? maybe your fuel system is working harder b/c of a restriction. good luck just wanted to chime in so you can solve the problem, good luck, 31,000 huh, wow

 

Yes, it has two tanks.... and the sending unit for the fuel gague doesn't work for the front tank. Idk if there is any rust or anyhting in the tank, so i dont use it. The gague always goes wayy past the full mark on the front tank. I should probably block this tank so there is no cross flow. Is there a way to do this? Or should i just replace the tank and the sending unit?

 

The fuel filter was changed about a month ago... Maybe ill just take it to a shop and have them do some tests and run some diagnostics and see if they can find out whats going on with this truck