2.3L ('83-'97) 2.3 Really bad gas mileage

[John501]

Hey everyone, I have a 1990 ranger 2.3 lima, 5 speed manual around 160K miles. It has the 3.45 rear end and I upgraded to 15 inch rims, with 235/75r15 tires i change the speedo gear to get the correct speed. This winter I've noticed a slow decline in my fuel economy, my last fill up was 14 mpg which is very low for a 4 banger engine. I have new spark plugs and wires, they are the standard copper plugs, and a new denso o2 sensor. I drive like a grandpa, if the truck sees above 2500 then I'm in a hurry. The driving I do is 70% highway/ 30% city, and I usually shift up at 1600-1800 rpm, since I have bigger tires now my rpm at 55mph is 1550ish rpm, and 60mph is a little below 2000 rpm. For the highway driving most of it is at 55mph, and some at 65mph. The city driving is at 45mph and I do shift into 5th but it drops the rpms to 1300. What is effecting my Gas mileage?? My 4.0 explorer 4x4 can get 19mpg driving the same route. I got this truck hoping for mid 20s gas mileage.

 

[Roert42]

engines have an optimal rpm to operate at, too low or too high and you will reduce that mpg. I can not tell you what that is for your engine, but I will say that your operating range seems a bit low for what I normally do, cruse around 1800 rpm.

 

[Dirtman]

You're shifting waaay to early.

Also have you verified your speedo is correct by comparing it to GPS speed? Speedo controls the odometer so if the speedo is off your not going to be able to calculate your mileage properly.

Also winter blend fuel sucks for fuel mileage so take that into account.

Also when is the last time you cleaned the MAF sensor and done a basic tune up (air filter, fuel filter, pcv valve etc)? How old are those plugs? Ford EDIS ingition systems should really never be used with copper plugs, it will destroy them very quickly. You should be running motorcraft or autolite double platinum, or iridium plugs.

 

[racsan]

3.45’s with 235/75/15 tires really puts a load on that engine, for those size tires & that engine you really need 4.10’s and even at that you will most likely be around 20mpg. There could be other issues as mentioned above but I think getting the engine to be about 2,000-2,400 @ 55 mph would help alot, youre effectively driving uphill or with a trailer (as far as working the engine) all of the time. 4.10’s would make it so much more enjoyable to drive. The best milage I ever got from a 2.3 was in a 2wd supercab ranger with 3.73’s and 215/75/14 tires (23-28 mpg) My current ranger is at about 20 mpg and runs 4.10’s with 225/70/15’s (winter) or 235/75/15’s (summer) It also had 3.45’s originally with 225/70/14’s. I didnt drive it much before swapping out the axle for 4.10’s Winter milage is always lower, no way around it unless you live in the south. Also I never use 5th unless im above 50 mph, even with 4.10’s I feel like its lugging.

 

[John501]

View attachment 55204

You're shifting waaay to early.

Also have you verified your speedo is correct by comparing it to GPS speed? Speedo controls the odometer so if the speedo is off your not going to be able to calculate your mileage properly.

Also winter blend fuel sucks for fuel mileage so take that into account.

Also when is the last time you cleaned the MAF sensor and done a basic tune up (air filter, fuel filter, pcv valve etc)? How old are those plugs? Ford EDIS ingition systems should really never be used with copper plugs, it will destroy them very quickly. You should be running motorcraft or autolite double platinum, or iridium plugs.

Thanks, I was starting to think I should leave it in forth in town, I've driven automatics all my life and I'm use to it shift in to od above 45, so I assumed the same for a manual. I did check the speed with gps, and it's spot on. I did a fuel pump and filter, with an air filter 4 months back. I just cleaned the maf, so hopefully that helps. I'm going to now try and keep the rpm cruising between 1800-2400 since I think that's the best efficiency range. I use to get 17mpg before the tires, but it has gotten colder now. Although I still believe some is not working right, since the fuel efficiency is supper low. This truck has an egr, can the effect fuel mileage?

 

[Dirtman]

Around town my truck gets much better gas mileage if I turn the overdrive off. I only turn it on if I'm going over 50. Like has been said if your RPMS are too low the engine is actually working harder. My truck is obviously an automatic but cruising at 65mph in OD my RPMs are around 2,500. With that I get mid 20 mpgs.

For your second question, if the EGR is clogged and stuck partially open it can definitely effect your mileage. The engine would generally run rough in that case but its never a bad idea to pop it off and clean it out/make sure it still moves. It's not too hard on a 2.3 provided the tube actually comes off the valve without snapping.

Have you checked it for any codes? It's obd1 system so sometimes there are codes without a check engine light on. There's a way to read the codes with a paperclip or by turning the key in some magical sequence but I can't remember the trick lol.

There's some other tests you can do like a range of vacuum tests, fuel pressure test, and a wet and dry compression test. These will rule out a internal mechanical problem, clogged exhaust system, leaking fuel injector, or failing fuel pump.

 

[John501]

Around town my truck gets much better gas mileage if I turn the overdrive off. I only turn it on if I'm going over 50. Like has been said if your RPMS are too low the engine is actually working harder. My truck is obviously an automatic but cruising at 65mph in OD my RPMs are around 2,500. With that I get mid 20 mpgs.

For your second question, if the EGR is clogged and stuck partially open it can definitely effect your mileage. The engine would generally run rough in that case but its never a bad idea to pop it off and clean it out/make sure it still moves. It's not too hard on a 2.3 provided the tube actually comes off the valve without snapping.

Have you checked it for any codes? It's obd1 system so sometimes there are codes without a check engine light on. There's a way to read the codes with a paperclip or by turning the key in some magical sequence but I can't remember the trick lol.

There's some other tests you can do like a range of vacuum tests, fuel pressure test, and a wet and dry compression test. These will rule out a internal mechanical problem, clogged exhaust system, leaking fuel injector, or failing fuel pump.

I'm going to experiment with the truck and only use OD Above 60mph and see how it effects the mileage. I haven't looked at codes yet it's been something I've wanted to do but never knew how. I'll look up instructions to do it. I did notice when I changed the spark plugs last, that they seemed to be running lean, so I believe there might be a vacuum leak somewhere. I'm going to guess the truck should idle at 700-800 which mine idles at 1000. I'll attach a photo of one of the plugs, and I'll post the rest when I get back home. I replaced everything back from the cat in the exhaust, the only issue being an exhaust leak where the cat bolts to the exhaust manifold. I won't get much more work done till after the the cold front where I live passes.

 

[Dirtman]

Yea 1,000 rpm is high idle for a manual trans truck. There's a quicky test you can do to tell if theirs a vacuum leak. Warm the engine up and unplug the IAC valve while it's running. The engine should stumble and almost stall. If it doesn't then you have a vac leak.

 

[scotts90ranger]

Back in the day my '90 would get 28mpg, I miss that... but that was with 3.08 gears and 195 75 14's, and that was in the 2000-2004 timeframe before the ethanol deal... everything I did to make the thing look better or whatnot worsened the mpg until it got down to ~23mpg, when I went to 4x4 it went to about 21mpg if I remember right, that was with 4.10's and 31" tires. Then turbo'd it and got about 18mpg, bigger tires and lower gears and 16... In all there's been 4 axles in the '90, 3.08, 3.73, 4.10 and 5.13 ratios

The '97 on the other hand is staying a commuter so I'm still going to screw with it but try to keep the MPG up. It has 4.10's and I've been screwing with tire size some hoping for better mileage but it doesn't seem to care... It had 225 75 14's when I got it (27" tall), got 22mpg (extended cab, somewhat heavy foot, but that doesn't seem to matter too much, I'm getting there) with the odometer verified with the speedo check section on the local freeway. Found a set of 235 75 15's (29" tall) and figured lowering the rpm would help, after checking the odometer with the freeway again it was 10% low and still 22mpg... those tires are hard so I found another set of tires in 225 75 15's this time and the odo is 7% low and now get 23.5mpg... I think a more efficient tread pattern is the key here...

In short, keep the R's between 2000 and 3000 and don't lug it down much lower than 2000 and I think that's the sweet spot with Lima's

 

[John501]

Back in the day my '90 would get 28mpg, I miss that... but that was with 3.08 gears and 195 75 14's, and that was in the 2000-2004 timeframe before the ethanol deal... everything I did to make the thing look better or whatnot worsened the mpg until it got down to ~23mpg, when I went to 4x4 it went to about 21mpg if I remember right, that was with 4.10's and 31" tires. Then turbo'd it and got about 18mpg, bigger tires and lower gears and 16... In all there's been 4 axles in the '90, 3.08, 3.73, 4.10 and 5.13 ratios

The '97 on the other hand is staying a commuter so I'm still going to screw with it but try to keep the MPG up. It has 4.10's and I've been screwing with tire size some hoping for better mileage but it doesn't seem to care... It had 225 75 14's when I got it (27" tall), got 22mpg (extended cab, somewhat heavy foot, but that doesn't seem to matter too much, I'm getting there) with the odometer verified with the speedo check section on the local freeway. Found a set of 235 75 15's (29" tall) and figured lowering the rpm would help, after checking the odometer with the freeway again it was 10% low and still 22mpg... those tires are hard so I found another set of tires in 225 75 15's this time and the odo is 7% low and now get 23.5mpg... I think a more efficient tread pattern is the key here...

In short, keep the R's between 2000 and 3000 and don't lug it down much lower than 2000 and I think that's the sweet spot with Lima's

Will do, I'll keep the rpm there and see how it does, also just a question. How fun is a ranger with the 2.3 turbo'd?

 

[scotts90ranger]

It's a blast, but since it's been a decade since I put it together for the most part some things need attention, there's times I wish I'd done a 4.0L swap instead since the 8:1 turbo motor has almost no bottom end, but when you get it up on the pipe and get it moving along it works great... I'm pretty sure it would leak less oil if I'd taken more than a month of evenings in the winter to put the engine together using only the best my spare parts box had to offer... which is why it doesn't get driven much anymore... that and the alignment moves too much, I'll get it dialed in then go wheeling once and the steering wheel is off 1/4 turn...

 

[Shran]

My last tank in my 4 cylinder truck was 13.8mpg. I think that's also the worst I've ever done. Something is going on with it lately but I have been very unmotivated to work on it at all. Usually I'm around 20 in the summer, high teens in the winter.

 

[Dirtman]

I don't even bother trying to check MPG in winter, it's always depressing...

 

[racsan]

In winter theres too many things that effect milage that you cant do anything about. (1) winter -blend fuel, (2) heavy oils that wont warm up right away when driving, like differentials, (3) youre engine isnt at top effenciancy until its fully warmed up, getting from 80 to 190 doesnt take nearly as long as when its 20/30 out. (4) if you’re driving through snow, thats more resistance and likewise youve got more weight in the back to help with traction. (5) tire choice, even with the same tire size, the tread design/aggresiveness can affect mpg’s, the best tires for quiet smooth summer driving and optimal mpg’s arent well suited to winter driving.
Thats a few things I can think of, Im sure theres more, just by themselves every item isnt much of a milage-killer but all of them added up does make a very noticeable difference. When I did check winter milage regularly it was generally a 4-6 mpg drop over summer mpg’s.

 

[Dirtman]

Ethanol content matters as well. You never really know how much ethanol is in the fuel you buy unless you test it. Most places allow up to 10% some I think go to 15%. But that doesn't actually mean there is 10 or 15% in it, its just the maximum allowed. The more ethanol in the fuel the crappier the fuel mileage.

So if one time you fill up and by some stroke of magic you get a tank of pure gasoline with zero ethanol and then next time you get a tank full of the maximum allowable ethanol content you will see a drop in MPGs between tanks. Not much but not nothing.