so uh what do i need to fix to get the mileage im supposed to be getting?

[mn_smokeater]

so the truck got filled up ehh a week ago full to teh 16Gal capacity and im on E now.

so travel distance was 190 miles, idle time under 1 1/2 hr total.

i know i should be able to go farther then that but why caint i?

Sensors?, Winter Blend Gas?, Injectors off?

 

[gwaii]

you been on the twin-turbo and 600 nitrous shot too much?


that could do it.

 

[mn_smokeater]

you been on the twin-turbo and 600 nitrous shot too much?


that could do it.

yup all that

only goes 55MPH 90% of the time

 

[gwaii]

no cel on?

i would think some sort of sensor is off.coolant temp or hego could do it.

 

[mn_smokeater]

no cel on?

i would think some sort of sensor is off.coolant temp or hego could do it.

one pops on and off

when il be going down the road it pops on and it shuts off when i key off

HEGO?

 

[kunar]

HEGO?

heated exhaust gas oxygen sensor

 

[gwaii]

my first guess would be the hego.....coolant temp would not be as likely to cycle on and off.any driveability issues?

 

[mn_smokeater]

yeah I got no power. Takes pedel to rhe floor to dojust 55

 

[RustedRanger]

One thing is to fill it up,drive it until you think your about out,then fill it up again and figure the mpg from the actual gallons used. Have you tuned it up recently? That makes a big difference. Driving style can up the mpgs as much as 30% also.

 

[rusty70f100]

It's probably a sensor or some combination of sensors.

Look through the tech library and just start testing things.

I'd start by putting a new o2 (hego) sensor on it.

Then fix the EGR if equipped.

Then test the TPS. Those are a yearly replacement item for me.

Make sure your air blend door is working. If it's sucking in -10F air all the time, the computer will compensate with a lot more fuel.

Check your timing, plugs, plug wires, cap, rotor...

Check your fuel pressure. Also check that the fuel pressure regulator isn't leaking fuel back into the intake.

If that all doesn't take care of it, then just start testing sensors. All of them.

 

[IRKillroy]

Rusty, I love your intentions but how can you tell him to test stuff then say to just start replacing expensive sensors?

@OP, More than likely you're getting crappy milage due to the fuel being used. the Ethonal in fuel has reduced fuel economy in the US since it was mandated to put AT LEAST 10% in there in order to reduce hydrocarbons emmissions. (god my spelling sucks).

Take into account that your ECU doesn't start to listen to you inputs until it's at 90 degrees, so if you don't cover your radiator like school buses and deisel truck owners do you'll probably never get there in the short trips you take (I'm from Michigan and it'd take 10 miles to warm up some days). I'm also willing to bet you got a fan attached to your engine that has seized up and is constantly "on".

As a note, when a HEGO stops working it'll usually tell the computer to run lean, and you'd get better fuel economy of sorts and really crappy performance.

let me know what you find to be the problem.

 

[rusty70f100]

-Sigh-

In order...

The only one I told him to replace was the O2 sensor. The only one. I told him to test the others. Usually the problem is the O2 sensor, so just doing that first could save a lot of effort. I know from personal experience on multiple vehicles that a failing O2 sensor will cause bad mileage.

Usually the EGR on these trucks is either non-functional due to years of neglect, or has been disabled by some half-wit that has no idea how it's supposed to work. The end result is the same, that being bad mileage, and a motor that pings itself to death. Perhaps I should have told him to check it then fix it.

The TPS should be checked because the computer uses it to know, well, the throttle position! When it goes bad, it can develop dead spots, usually off idle. The computer thinks "OMG he floored it!" and runs it rich for a little bit until the O2 sensor or the MAP sensor tells it otherwise. In other words, it screws things up when it's bad.

A lot of times on these older vehicles, there is more than one problem. Take the time to find them all.

As per your comments, I get over 20mpg in the winter with my '87 B2. Last tank was 21mpg, all short trips. Last summer I got 26mpg out of it on a trip. All I ever run is E10. His 2.3L should be able to do better than that.

The fan clutch is a good thing to check. I'm glad you brought it up.

 

[exbass94]

so the truck got filled up ehh a week ago full to teh 16Gal capacity and im on E now.

Broken/inaccurate gas gauge. Find out your actual mpg and get back to us.

 

[mn_smokeater]

will read more of this in morning brain to sleepy to combrinrehend cafffeein going out crahing time

 

[bruker]

Two obvious thing come to mind.

1) Is ther a small hole in your gas tank or fuel line?

2) 1-1/2 hours of idling, I know you're not using a lot of fuel but when idling you're getting 0 mpg.