91 Explorer 4x4

[ExplosaBlazin]

I have a few questions so please bare with me. One of them is I was wondering how everyone's mileage is on the old 4.0 OHV that I have in my 91. It currently has 148,000 miles on it original engine and tranny. Mobile 1 and premium octane have only been used. Only mod that I have is a K and N airfilter. I accelerate really slow because I feel that my car is going to die because of things I have heard about the old Explorers. My car is in prestine condition and runs very well. The odd thing is with my slow acceleration, typically under 2k rpm, I get about 15 mpg with a little bit of highway driving.

 

[ExplosaBlazin]

Another question that I have is how far should I go offroad when I take my explorer in the dirt. I have goodyear tires that aren't made for offroading, they are just snow tires and I was wondering if it was going to trash my car if i took it in the dirt, but didnt do anything crazy. BTW, the 4x4 has rarely rarely been used.

 

[Alec]

The motor should last a long time. However, you're not helping it my giving it higher octane. I recommend running about 3 tankfuls of injector cleaner and using 89 octane from now on.

It's not the motors you have to worry about, it's the tranny.

 

[Alec]

They're made to go offroad, so as long as you know your limits you'll be fine. There are many of us that have taken our trucks on really hard trails in stock or mostly stock form.

 

[ExplosaBlazin]

Well, my dad has always put it in and since he pays for gas he wants me to put in 92. I heard that it's better to put in the recommended. If it were me paying for gas, i would definately be putting in 89...Is it wise to switch or just stay with what I'm putting in. What is worth using in my gas tank and what products are gimmics. I want my car to last a long time and run strong.

 

[Alec]

higher octane doesn't help anything unless your computer is designed for it. You're just causing possible damage to the engine and catalytic converters. Please run a few tankfuls of fuel system cleaner and/or get your fuel injectors professionally cleaned and then run 89 octane. You are actually causing more harm than good with 92.

 

[ExplosaBlazin]

What fuel system cleaner do you recommend and what will it do? A friend of mine has a 93 trans am and uses restore for his car and says it works.

 

[Alec]

I usually use Chevron techron concentrate, Gumout concentrate, or STP cleaner.

 

[ExplosaBlazin]

I used STP gas saver or whatever, I heard that all of those chemicals are hoaxes and don't do any good.

 

[poconosms1]

I have 178k on my 92 w/original trannie - I service trainnie 80-90K.

Running high octane all the time is generally not good for non-high performance vehicles. High octine burns hotter, which is why it "cleans the motors".

If I can rember this the right way. The octane the manufactures call for is a different rating than the octane displayed at the gas station. The for ex call for 89 octane based on the "research method". this translates into 87 octane at the gas station. Next time you pump gas, you will see the formula for determining the octane printed on the pump.

 

[MyExpWork]

I have a 91 XLT 4X4 with 167,000 miles. I have typically used 87 or 89. It runs great on original motor and tranny. Its my daily driver.

I just got back from a trip to Vegas which as you know living in LA its about 300 miles. We got there in about 4.5 hours and home in about the same averageing about 80mph, no problems.

I have a k&N cone filter and a bigger MAS on mine. I am pretty easy while driving but when need to pass or something I have full confidence. I usually average about 17-18mpg in 50-50 city & highway driving.

I also tow a 2500lb trailer every weekend in the summer.

Good luck with it.

Brian

 

[ahhjaws]

I have a '92 with about 145K. Engine is fine, but I had to replace the tranny. I take it offroad all the time, it is very capable.

I use 91 octane now, just because I have a chip and it requires 91.

 

[andypinto]

Hi guys:

I very worried after read this thread because here in my contry you can only get 93, 95 and 97 octanes gas, and my mechanic (from a Ford dealer) suggested that I only pump 97 octanes gas to deal with a pinging problem in my 92 XLT 4x4 X.
By the way, after change from 93 to 97 octanes the pinging just dissapear.
But now you guys tell that in no good for my X engine.
Could anyone explain how an expensive, full of additives and detergent high octane gas can harm the OHC 4.0 engine?

Thanks in advance and happy trails

 

[woodychitwn]

It does dammage by burning hotter, thereby causing more wear and tear on the internal components. But if that's all that's available, check you owner's manual. Ford probably compensated for the higher fuel ratings in Chile by making adjustments to the engine's computer.

 

[ExplosaBlazin]

I was also wondering if a K and N airfilter does anything in performance or gas mileage. I installed one and i noticed that it does have a little bit more power, but didnt notice it in my mileage.

 

[TPLYNCH]

If your engine is pinging using 87 (or 93 for AndyPinto), the first thing you should do is clean the MAS. A dirty MAS will cause your pinging problems. Next thing to do is retourque the intake manifold gaskets (don't remember if there are upper/lower) that are known to come loose especially on the first generation Ex's. Putting in high octane gas in an Ex is a waste of money (unless you have a performance chip as mentioned above), and if you're doing it for pinging, not fixing the real problem.

 

[andypinto]

TPLYNCH, when you talk about MAS, that mean the Mass Air Flow sensor?
Well, I already clean the MAF sensor, as directed in other thread, and a little hesitation in idle just dissapear (the filament of the MAF was very dirty, with 10 years of accumulated dust and other stuff).
I didn't retorque the intake manifolds but I try to do soon.
I believe that my X computer don't have any compensation to deal with the gas octane avalaible in Chile, because I bought my XLT in USA.
Anyone knows about a chip that make the computer to deal with?
Woodychitwn says that the high octane fuel burns hotter than the lower octane gas. That means that the overall temperature of the engine is higher than normal?
I never noted any overheating in my X engine, neither when I switch to 97 octanes gas.
The coolant temp gauge always stays in the normal zone even with the A/C in full in a hot day (as usual in my city, wich is located in the Desert of Atacama, the dryest of the world.).

Thanks

 

[Alec]

Higher octane gas does not cause problems by burning hotter, it causes problems by burning incompletely. The left over carbon from inefficient combustion leaves carbon deposits on internal engine components, esp the injectors. It also fouls the cat sooner because the cat tries to burn the unused fuel itself.

 

[Msupertek]

Ford Certified Technician

Just to let you know my X has about 150,000 miles on it and tons I mean tons of mods and my GAS PEDAl only has two positions UP or DOWN TO THE FLOOR, my gas mileage is (who cares) and thats good enough for me!

 

[TPLYNCH]

Andy, there are several chips out there. Run a search for "performance chips" or "chip recommendations" and see what comes up.