Foot on the floor to keep up @ 55 MPH, poor mileage

[ExploreNW]

Hey! My new '94 Ranger came with "some love required" and she's running a bit slow. I'm no stranger to the under-100hp club where half of my junk has started its life. I've driven two other 2.3s, one '80s and one in a '01 Mazda truck and they weren't anywhere near as gutless as this old girl is. I'm usually in 4th gear up to 55-60 when I shift into OD. Going up any sort of hill I'm almost to the floor, on the floor, or dropping a gear and almost to the floor in order to keep up with Oregon's already pathetically low speed limits. I'm getting 19-20 MPG in a truck rated for 27. Stock ride height and everything else. Scan tools and chips for EEC-IV seem to be a lot more expensive than a carb & cam swap so if anything I'll hit the junkyard next weekend.

Work I've done: intake air restrictor delete, new stock air filter, new "least expensive" Autolite spark plugs.
Irrelevant maintenance: new timing belt & tensioner the day after I got it.

Do you guys have any better ideas for me to either stick some nuts on this thing or get some MPG back?
Cheers

 

[Curious Hound]

Is your throttle cable stretched? Check out the throttle cable zip-tie mod in the tech articles.

Thermostat and fan running ok and maintaining proper engine temperature?

What about fuel filter?

MAF sensor dirty?

EGR working properly?

Honestly, I'm guessing on some of these. Just trying to help think of anything that could have an effect. Are you running stock size tires? If not, that can have a big effect. Also, if running wrong tire size but speedo gear hasn't been changed, that would throw off your mpg calculations. What about aerodynamics? Have you added a ladder rack or anything that would add drag?

 

[Nez'sRanger]

Is your throttle cable stretched? Check out the throttle cable zip-tie mod in the tech articles.

Thermostat and fan running ok and maintaining proper engine temperature?

What about fuel filter?

MAF sensor dirty?

EGR working properly?

Honestly, I'm guessing on some of these. Just trying to help think of anything that could have an effect. Are you running stock size tires? If not, that can have a big effect. Also, if running wrong tire size but speedo gear hasn't been changed, that would throw off your mpg calculations. What about aerodynamics? Have you added a ladder rack or anything that would add drag?

Spot on! I think the stretched cable will definitely be an issue here. I had my dad watch the throttle body on my truck while I floored the gas (engine off, of course), and he said it only opened the butterfly halfway!
Between that and a new fuel filter, you will likely feel a night and day difference!
Only thing here, a 94 shouldn't have EGR, especially with the MAF system, so I'd just be sure to clean the MAF sensor.

 

[Shran]

Sounds about right for a 2.3 in '94. None of mine have ever averaged over 20mpg. Beyond the normal maintenance stuff suggested there is not a whole lot that can be done about it... they are very heavy engines based on a design from the 60's. Deeper gears in the axle(s) will make it feel snappier from a stop and smaller tires can make a difference there too. Tuners and chips and stuff will not make a noticeable difference.

 

[fastpakr]

I'd give it a compression check while you're diagnosing. Knowing that's good will at least tell you whether to suck it up and deal (low compression) or keep looking for other causes. For what it's worth, I got about 19-20 around town in my '94 but consistently got well into the 20's on the highway. As I recall, I hit 26 or 27 on one long trip.

 

[rusty ol ranger]

Pissing in the dark but....

Did this start after the timing belt change?

After having a few 1.9L escorts, i can tell you having that timing gear ever so slightly off will cause exactly what your saying.

If not that, i second the compression test.

 

[ExploreNW]

Is your throttle cable stretched? Check out the throttle cable zip-tie mod in the tech articles.

Thermostat and fan running ok and maintaining proper engine temperature?

What about fuel filter?

MAF sensor dirty?

EGR working properly?

The thermostat is good, I replaced it when I had the timing belt cover off and everything was out of the way. Stock 192*F unit with a jiggle valve, I think Delco. Fan clutch is good, spins free. The dash temp sender does not work, when hot it barely touches the "N" in Normal and this didn't change with the new thermostat. Heater will blow hot. I bought a replacement CTS but the harness has a egg shaped round (?) connector where the new one is the normal rectangular plug. I can't see a reason not to change the fuel filter, just haven't picked one up yet.

Today I pulled the top of the air cleaner and the MAF out to clean. It looks like an aftermarket unit, nice and clean! Blew 1/4 can of MAF cleaner through it just to make sure. While I had the top of the box off I pulled the hot air WTF and cold air intake out of there & capped the vac line. I hooked some line onto the EGR, sucked on it, truck quit right away. Next thing to check is the throttle cable, just need a brick.

Only thing here, a 94 shouldn't have EGR, especially with the MAF system, so I'd just be sure to clean the MAF sensor.

I seem to have EGR, it's not a Cali emissions truck either. What did Ford do that year for CA?

Sounds about right for a 2.3 in '94. None of mine have ever averaged over 20mpg. Beyond the normal maintenance stuff suggested there is not a whole lot that can be done about it... they are very heavy engines based on a design from the 60's. Deeper gears in the axle(s) will make it feel snappier from a stop and smaller tires can make a difference there too. Tuners and chips and stuff will not make a noticeable difference.

Looks like you run lifts, I haven't gotten that far into the project yet but if I'm at 20 now I'll get better mileage in my F250... Not surprised about the heavy engines or Ford under-gearing the 2wds. What do you make of the stock mileage chart on this site? 80s trucks at 35 MPG on carbs?

Pissing in the dark but....

Did this start after the timing belt change?

After having a few 1.9L escorts, i can tell you having that timing gear ever so slightly off will cause exactly what your saying.

If not that, i second the compression test.

It seemed just as bad before swapping belts. Seems to idle a little shaky, otherwise no symptoms that'd come with low compression but I'll certainly check that out.


Thanks for all your help guys! I spent some time in the garage today and tore into this thing a bit more. Ended up finding the manual pouch and complete service history through 150k tucked in under the drivers seat, it looks like she took it into Point-S every 5k for oil and the filters were all changed on schedule. It seems well taken care of but well used. Still stock ride height with 215/75r14s on stock mags. With the hot air WTF pulled out of there and a clean MAF it seemed to do a lot better on the freeway but ideally it'd have an e-fan conversion. Feels kinda gutless and the journey is still out on mileage - might take it up to Spokane this weekend to see my folks.

 

[Nez'sRanger]

I take that back. I was getting the 2.9 and 2.3 messed up. Yours does indeed have an EGR... Which should be checked!

 

[RonD]

Use Vacuum gauge, best tool to diagnose gasoline engines, $20

No matter how many things "they" add or change, the engine is still a self power air pump
And you test pumps by testing pressure, in this case suction pressure, vacuum

Good read here if you don't use vacuum gauge much: http://www.gregsengine.com/using-a-vacuum-gauge.html

Exhaust back pressure is a big power robber on older vehicles, you can test for that

 

[ExploreNW]

Good news! Drove the truck around all day yesterday. Removing the hot air intake wtf valve (not sure what to call it... the horsepower deleter?) and cleaning the MAF gave me a whole different truck. Doesn't feel as good as the older Ranger I drove so I'm still a bit concerned about the truck. However I got over 100 miles on 1/3 tank, I know the gauge isn't the accurate way to measure but I was only getting about 200-225 miles per tank before.

I checked the EGR with the vac line & mouth method and the engine died right away. It seemed to take very little vacuum to snuff out the engine so I'm not sure about that but the vacuum diaphragm and flow tubes do work. Next step is, as RonD says, hook up a vac gauge. My cousins suggested a delete but I want to keep the EGR for more highway MPG.

The engine has almost no blow-by and doesn't smoke. It sounds like there is an exhaust leak in the system somewhere so I crawled under there and coudn't find where it could be. Possibly a plugged cat or a really restrictive stock unit behind the factory shorty. I've been planning on installing a 2.25"-2.5" exhaust since I got the truck as I have a ton of 2.5" exhaust parts (anyone want a fresh cat?) sitting around in the shop. That project might happen sooner than expected.

 

[adsm08]

Exhaust back pressure is a big power robber on older vehicles, you can test for that

What about network back pressure? I never really understood how that worked.

 

[BPLP]

Seems to idle a little shaky

This makes it sound like you might have a vacuum leak somewhere. It wont hurt you MPG's that much but it is something that you should clear up.

 

[rusty ol ranger]

I take that back. I was getting the 2.9 and 2.3 messed up. Yours does indeed have an EGR... Which should be checked!

2.9 does have an EGR to. Atleast 86/87

 

[Nez'sRanger]

2.9 does have an EGR to. Atleast 86/87

Yea... By the time my 89 came along, it was history. When doing the MAF conversion on a 2.9 with EGR, the conversion requires you to remove it. I didn't realize they still used EGR in other engines well past that year till I looked at my work truck (a 92 2.3 ranger) and after a quick Google, I guess lots of vehicles still use it. Learn something new every day, right! That's why I love this website!

 

[tomw]

I'd check fuel pressure and delivered volume over time. If you starve it of fuel, it will need WOT, and the compute will stuff in as much fuel as it can(almost) even when limited by faulty pump or plugged filter.
tom