Do I need an OBD1 to check my poor gas mileage

[Angry Possum]

Would an OBD1 computer help to diagnose my hectic gas mileage. It's truly horrific at 11mpg combined highway and city. It's all tuned up, plugs, wires, air breather, fuel filter PCV, I really don't get it man.
4800 lb 1993 XLT Ranger Extended Cab 4.0l, Automatic 4x4. I'd be happy with at least 14 combined.

 

[Angry Possum]

Would an OBD1 show the fuel air ratio etc?

 

[Angry Possum]

Someone said to change the 02 sensors, for better gas mileage. Is this true?

 

[gaz]

@Angry Possum ,

Is your engine using (burning) oil or does it maintain a constant oil level until the oil change is due?

Are you using a crank shaft driven fan/clutch?

What is your gear/tire ratio/size? What tire pressure do you use? What do you torque your wheel studs to? Is your alignment good?

Are you using the stock size exhaust tubing?

What type of air filter are you using? What size and type of spark plug wires did you select? What brand and heat range spark plugs are you using? What temperature T-stat are you using? What percentage water to coolant do you run? How much do you use your a/c? How fast do you drive on the highway? How quickly do you accelerate from a stop? How soon do you take you foot of the gas when approaching a stop? How much extra gear to you keep in your rig?

I would not be happy with less than 20/25 city/hwy or better mpg with the OHV 4.0l.

It has been said that the worst aspect of a vehicles's performance is the operator, the efficiency of the power plant and chasis can be improved.

 

[Angry Possum]

@Angry Possum ,

Is your engine using (burning) oil or does it maintain a constant oil level until the oil change is due?

Are you using a crank shaft driven fan/clutch?

What is your gear/tire ratio/size? What tire pressure do you use? What do you torque your wheel studs to? Is your alignment good?

Are you using the stock size exhaust tubing?

What type of air filter are you using? What size and type of spark plug wires did you select? What brand and heat range spark plugs are you using? What temperature T-stat are you using? What percentage water to coolant do you run? How much do you use your a/c? How fast do you drive on the highway? How quickly do you accelerate from a stop? How soon do you take you foot of the gas when approaching a stop? How much extra gear to you keep in your rig?

I would not be happy with less than 20/25 city/hwy or better mpg with the OHV 4.0l.

It has been said that the worst aspect of a vehicles's performance is the operator, the efficiency of the power plant and chasis can be improved.

I don't over accelerate, I drive like an old man some tell me. But I am 60. My Highway driving is in the low to mid 60s tops. I'm using a decent fan clutch I got off Rock Auto with the regular stock fan blade. Wires are Motorcraft. Bosch Fuel Filter. Titanium Spark Plugs. No AC Yet. Tires Stock Size 235/75/15 and well inflated I may add. Thermostat unknown. 50-50 Coolant. I do have a stock cap on my truck also (pic enclosed), if that helps. Regular new air breather. New PCV valve.

 

[Angry Possum]

Again, Would an OBD1 help me gauge how my truck is performing? That's my biggest question.

 

[superj]

obd1 i don't think gives as much info versus later stuff. might be better the put a vacuum gage on the engine and see what that shows.

 

[Uncle Gump]

@Angry Possum ,

I would not be happy with less than 20/25 city/hwy or better mpg with the OHV 4.0l.

I'll just go ahead and say it...

20 city and 25 Highway is unrealistic from a 4x4 4.0L. It exceeds the original EPA estimates by 3/5 mpg's. The factory numbers were rarely achievable when new.

I'm not saying 11 mpg's is ok by any means... because it's not.

OBD1 has limited functionality when it comes to scan tools. you can't just pick your parameters and monitor them like on OBDII vehicles. They're really glorified code readers.

 

[rumblecloud]

This is from my '94. I doubt yours is much different...I don't drive mine enough to know - or care - what I am actually getting.

 

[Blmpkn]

02 sensors, yeah, meaningful effect on efficiency. They degrade with time/miles, whats @RonD always saying... 10 years or 100k miles?

 

[holyford86]

Higher end scan tools can give you some very limited live data if they are equipped to do so and the EEC supports live data (some don't) 11mpg is pretty standard from a 4.0 automatic in combined driving, at least in my experience. My 4.0 swapped first gen with 4.56s, 6 inches of lift, an M5OD, a heavy duty fan clutch, and a Buick supercharger cobbled on the top somehow gets 15-17 MPG. The completely stock 93 Explorer that the engine came out of (A4LD equipped) was lucky to get 13mpg. Kind of an apples to cheeseburgers comparison but it should give you an idea.

 

[Angry Possum]

Thanks everybody for the posts. I'm gonna try the 02 sensors. I'll probably get them from Rock Auto, I think I need 2 total.

 

[superj]

Man, that 4.0 in a ranger almost gets the same mileage as a full sized truck. No wonder the four cylinders where the most common version sold.

 

[Angry Possum]

Man, that 4.0 in a ranger almost gets the same mileage as a full sized truck. No wonder the four cylinders where the most common version sold.

Tell me about it. I'd be happy getting 14 city and 20 hwy. But 11 mpg combined, is F¢π...ing atrocious, especially with the high gas prices now. This engine is literally a Pig. I may try installing a new MAF and some new O2 sensors. Let's see how that goes.