Truck seems fine normally. It's not the quickest but keeps up with traffic. But when I tow with it it seems very underpowered. Cant really take trailers on the highway. Usual have the pedal to the floor I can make it up to 65 in 4th gear eventually. But when I shift to 5th gear I drop down to 60mph. Trailer weighs about 2k lbs. Truck is rated to tow 4k. Is it just my engine or is the OHV normally have no *****? I was thinking about overhauling this engine, but maybe I'm better off swapping it out? The SOHC has maybe 100 more HP. If I cant even pull a small trailer on the highway the engine may not be worth it to rebuild.

 

4.0l OHV has 160hp but 220ft/lb of torque
4.0l SOHC has 207hp(premium gas) and 238ft/lb of torque

So a bit but not much gain for pulling with the SOHC and you would need to run higher octane to get that extra torque

Have you checked the throttle cable?
these stretch over time and you lose full throttle and never even notice it happening, just notice less power
Use a stick to hold gas pedal down then check at the engine if you can open throttle more
If so google: ranger throttle cable mod
easy fix

Check vacuum at idle, 18-21" is expected
Lower means less power

O2 sensors
They last 125k miles or 10 years
Then they start to show lean and computer runs engine too rich so less power, hows your MPG?
If its been slowly dropping could be time to change upstream O2s

 

Truck is 27 years old with 190k miles. O˛ sensors look original. Truck tends to run rich I believe. If I put the air filter on I get a rich code.

 

As far as throttle cable goes I know that's not a problem because I get peak power pressing 1/4 way to the floor. If I press gas pedal more it doesn't go any faster.

 

MPG will improve with new O2s, they pay for themselves 2 or 3 times over for the next 125k miles

4.0l OHV makes best power/torque at 2,400rpm so you want to keep RPMs in the 2,200-2,600rpm range when pulling a load, and this depends alot on rear axle ratio and tire size, as to what gear will work best, 3rd, 4th, or 5th, not speed, base it on RPM


Stock air filter has 200% air flow so would have to really dirty to restrict flow to engine
Pull out and clean the MAF sensor

Also change PCV Valve, every 3 oil changes
And check Breather hose for oil residue, that means PCV valve is not doing its job

 

its not factory air, previous owner put a CAI on it. An aluminum tube with a round filter on it. Its basically black the filter is so dirty. I want to reuse factory air box but need to find a intake tube. Or maybe I can rig up that aluminum tube with some elbows to reach factory box?

I'll look into replacing o˛ sensors. Pcv valve was dirty but it still shook loose. Although there was a good amount of oil in the intake area.
4th gear runs high on the highway. About 2500-2800 rpms doing 65mph maybe 3k rpms doing 70. 5th gear says overdrive on the stick. That runs about 2100 rpms at 65.

 

5th(OD) would be fine with no load but can't be used with trailer or even heavy bed load, even going up a steep hill you should be in 4th at 65mph

My 1994 4.0l has same setup as yours, 2,100 at 65mpg in 5th, so you probably have a 3.73 rear axle ratio if tires are 28"/29"

5th is a negative ratio, under 1:1, 0.79:1 I think, so not alot of torque anyway, its there for better MPG when cruising at highway speed with no loads

 

Just a lil discouraging with all the cars blowing by way faster than me as I struggle to do 65. Average speed is 80mph here.so I'm going about 15mph slower than everyone else with my engine screaming like a jet engine in 4th gear. Feel like I'm gonna break something at that high of an rpm. Over 2500 rpms engine doesn't sound happy. Usual like to keep it around 1500.

My last truck was the f150 with the 5.0 motor. I could tow a trailer like this and forget its back there. So I guess I'm expecting too much from this engine.
5.0 puts out 412HP I'm reading

 

I guess I'm wondering if its possible to make a bunch more power with these engines? It's only about 20hp more than my honda civic. Thought it was the pushrod design holding it back but the LS motors used in corvettes are pushrod engines. Nascar uses pushrod. For a relatively large engine there has got to be a way to make at least double the stock power. Is there?

 

Then drive at 75-80mph in 5th

I had a bad fan clutch that vibrated above above 2,400rpm when I first got the 1994, so didn't think the engine liked the higher RPMs, lol
When it finally got worse I figured out the problem, then it was fine

The 4.0l OHV doesn't make best HP until 4,200rpms so it can be REVed as much as you need, but if it "feels" funny then could a have a failing fan clutch or water pump bearing

 

yeah the fan is always blowing. And blows real hard when the engine revs.

 

heck, my first Flathead would do 130 with no overdrive (speedo read to 100, needle passed that, passed the odo, stuck on the backside of the zero peg). Probably a Merc 255 cube. My 4.0 pushrod has lots of power, when it isn't trying to shake itself to death.
Engine off, spin the fan. If the clutch is shot and locked, fan won't spin, Good spin should give at least a 1/2 to 1/2 turn before it stops,

 

I can move fan but feels like its moving through molasses.
as far as my engine goes I suspect there is a misfire as the exhaust sounds like I have a cam in it. Just wondering if I bring this thing back to its former OEM glory will it be a good tow rig for small trailers? Or should I sell it and find a used f-150. Only thing more common in the old beater category than the ranger or s10 is the f-150. Americas most popular car for ages. Local junk yard has like 30 f150s maybe 8 rangers.
I really did want the gas mileage of the ranger though.though combined gas mileage in the 20s was quite the selling point. Guess there is a tradeoff. Power or economy

 

You will never get MPG in the 20's with 4.0l OHV or SOHC, the 4cyl Rangers could do that
17/18mpg with a 4.0l would be about the best, all highway and under 70mph

A later model F-150 can do about the same depending on engine and cab setup, of course


To test a fan clutch, start Cold Engine, count to 10 slowly, so 10-15 seconds, shut off engine, spin the fan now should be easy to spin, unlocked

After getting home from at least a 20min drive, shut of ngine and spin fan, should be hard to spin, locked

If fan feels Locked when cold, fan clutch is bad

 

I'll try that test when I get the cooling system put back together.
The f-150s in my price range lucky to get 12-15mpg. Around $1000. I know the new EcoBoost engines do that but dont want to spend $15k+ on a work truck.

 

Part of my criteria picking and old project is how common it was how easy it would be to find other parts vehicles etc.. saw an old triumph two seater sports car for sale for 1k body was descent but needed work to be drivable again. Kinda looked like a lil Ferrari. Then I found out why it was so cheap. Nobody makes parts for it. Rock auto had maybe 2 parts available for the whole car. Basically I'd be fabricating stuff. That's why it was so cheap.

 

This 94 ranger I bought for $900. If I got it in good working condition and fixed some cosmetics at most its probably worth 2-3k I've probably put a grand into it already. Wasn't planning on putting more than the trucks worth. That way I could just turn around and get my investment back. But I'm starting to like this lil truck. Getting everything done I want to do would be overspending the value. But I'm thinking I'll do it.

 

On older vehicles its never about what its worth, its about what it will cost you to drive it for X months or years
If you spent $2,000 on a vehicle and can drive it for 2 years, 24 months, thats $83/month and then its free and clear
If you spend another $1,000, so $3,000, but then it would maybe last 4 years, 48months then its only costing you $62/month

And then you still have the value of the running vehicle after that

That's why buying a vehicle with a bad engine or transmission might not be a bad deal, if the rest of the vehicle looks like it can take another 2 to 5 years of driving for a $3,500 investment(vehicle and repair) then its way better than a $200-$800/month car payment, lol

 

Great points. Also with an old vehicle you can stop repairing it any time. Last truck was a leased f-150 that cost $500/mo $600/mo with insurance. If money got tight I was still on the hook for that price for 3 years. With this if I have a slow month I can just put it on the back burner. I have another car so I dont need this. Just need it for pulling trailers. And that I cam put on hold if needed.

 

I'd assume with 2WD models its not to hard to change out the rear axle (i would assume for speed accuracy there's a way to change out the speedometer gear at the transmission like I did with my Wrangler). I would guess you have a 3.08 like mine. If I was doing a lot of towing I'd sacrifice the MPG for a 3.55/3.73, I'd also be nervous about putting to much strain on the A4LD transmission (If its an automatic) with the 3.08

 

manual transmission with that 8.8" rear end idk gearing.
It came with 16" wheels from previous owner. I bought some 14" wheels for it the oem size. Gets much more torque low end with those but highway speeds are at a much higher RPM. Used to do 80MPH at 2300 rpms. Now it goes about 68 at same rpm