It's a '93 wagon and I drove 148 miles with all but eight being highway. I drove mostly between 70 and 75 mph (solo with only a light tool box on board) and I calculated that I got 13.2 mpg. It ran good but idled a little rough when I got off the freeway.
That seems low compared to the last 240 (90 sedan) I owned, but I could be mistaken.
The previous owner told me he bypassed the OD solenoid by creating a channel between the two holes on its top.
So, if that is low mileage what might be some not so obvious reasons for it?

Thanks for all of your responses.
Yesterday as I was checking the grounds on the intake manifold and testing the O2 sensor I discovered that the small hose with the check valve (which is for?) was disconnected. After reconnection the engine runs smooth again.
So I'll retest my mileage, which is about half and half highway and city but should be better than 13 mpg.

The one at the top of the manifold that sticks out towards the passengers side? That's the HVAC vacuum check valve, if it was disconnected, none of your vent/defrost would work.

I've been calculating my mpg for several years with my daily driven stock '90 245 AW70 which includes a variety of city and highway driving. I actually just put 900 miles on it this past weekend between my gf's parents house in the Poconos, back to our place in Baltimore, as well as my Parents house outside of Philadelphia. I average about 19 city and 24 hwy, a bit better coming back from the Poconos because its all down hill. I typically drive between 75/80mph on the highway turning ~3k rpm, I'm really not shooting for good mileage, I just monitor it.
These numbers have been very steady over the past few years, but I plan on pulling the intake mani, cleaning it out, putting in lower mile injectors and replacing the FPR and intake gasket; hopefully I can pull a little more out of it.

Your numbers are pretty low, I would definitely look into what issues might be occurring. Have you ever cleaned your throttle body? Tune up? What do your plugs look like?

Have you checked for any stored codes in the OBD?

I always find the experiences of others in the arena useful. We all have different driving conditions, styles, volume of stuff/passengers, etc. With my 1990 240 AW70 sedan I averaged very similar in the 8 months per year I could get "summer blend" fuel but once winter blend hit, I dropped to about 17 mpg city part of this was surely longer idle times while I fully cleared the car and bit from from pure joy of doing 4-wheel power slides in the snow on the deserted roads into work at 5 AM.

My 940 NA AW70L Wagon drops to about 16 city but that is 100% my fault. I wring every last bit of performance out of the B230F as the heavier car really is taxing the limited horsepower. If I drove with the pace of traffic, it would be higher as I do manage to match or beat the highway performance of that old sedan (24-25 mpg at 70 mph...better if I drop down even 5 mph).

Back further, my 1979 B21f, BW55 wagon got more than 20 city and highway varied DRASTICALLY regarding cruising speed. It would do 75 mph all day long at about 23-24 mpg while dropping it to 60 mph could get me 26-27 mpg. My 1976 M40, B21F sedan could get me about 31 mpg on the highway at 60 mph.

I have three 240s that I drive on regular basis and I check the mpg every tank. All are well tuned.
The 88 wagon gets 22 in town and 25-6 @ 65 highway.
The 90 wagon 5 speed LH3.1 gets 24 in town and 30-32 @ 65 on the highway. I have been able to achieve 35 by holding to 60 mph and coasting down long hills.
The 90 sedan with 60,000 miles get 23 in town 26 highway.

I think you have a dragging brake.

Hawkeye

hi hawk- those are good figures for mpg. mine does the same with the 5speed od. keep the tire pressures at 33 cold. the wagons are a heavy vehicle too which you would think would retard mpg. if i let the tire pressures drop below 30 mpg drops about 2 mpg. with cars like these have you been asked to join the cba? thanks tons oldduke btw have found generally that a heavy car, 4 cyl engine when coupled to an automatic trans drops the mpg to stinko levels.

OD,
What's the cba?
Hawk

hi hawk- a legendary club known for educating smart consumers to expose scams, shysters, clip joints and superchargers . cba stands for cheap bastids of america.do you want to join. only practical intellectuals are allowed in. regards oldduke

Assuming you math was accurate (tank was full at the start and full at the end, correct speedo in the cluster, correct tire size, etc) that is horrible. It is so bad that I would have to assume a dragging caliper.

Sure, I guess the O2 sensor being bad could drop you to to 15-16 mpg. Variuous other little things can get you in that range but 13 mpg is more like a cruising speed of 90 mph.

Hello,

If you were driving a full size pickup that would be normal.
You ask,
"So, if that is low mileage what might be some not so obvious reasons for it?"

Bad maintenance or a worn out engine. Just how rough is this car mechanically?
A tune up might help. You have to be running rich somewhere besides on the highway.

If it starts up when cold and just chugs along you might be looking at a bad fuel pressure regulator.
Then again, the coolant thermostat is stuck open. Does the temperature gauge go up to about half way?
A engine temperature sensor for the computer, not the instrument gauge, can be bad as well.
All three affect mixture.
A tune up in the ignition area will have to be considered or least factored in since you are apparently dumping fuel and the O2 sensor is probably contaminated.

So here is a question.... Does the Check Engine Light bulb work in the dash when you turn the key.
This type of mileage should have that light glowing!

Get back to us with more details on the cars condition.

Phil

hi sages- mpg is always a good barometer of engine condition if you first establish a pattern or baseline for your particular vehicle. have run a 92 245 for 5 years now, mostly around town suburban driving. a few years ago replaced plugs, rotor, cap ,air filterand wires. mpg went up to 24 around town and 29-30 on hwy and has stayed there since. non functioning ac.believe a big factor is the 245 has the m47 5 spd with 3 floor pedals. a few folks here have the wagon like me but have the automatic trans. all get lower mpg in the 18-23 range. have had the same experience for many years with fords and dodges. keep up the good work. thanks tons oldduke

What Phil said +1.

"The previous owner told me he bypassed the OD solenoid by creating a channel between the two holes on its top." So does that mean the overdrive was on or off on the highway?

The bypass means OD cannot be locked out...this is assuming they did not end up getting some gunk in the passages.