So my car does have problems that I'm hoping new plugs, rotor/cap and filters will fix. I'm getting 16 mpg now but was getting around 18-19 before. Another 240 owner I know said he feels lucky if gets 20 mpg on average. What about you - combined hwy and street driving mileage? Someone posted before that he was getting 26 mpg. If that is the general concensus, I better take my car to a shop!

'91 245, 5-speed LH 3.1 modified VX cam + 5 deg, 16v injectors, sport exhaust, ign advanced to 14 deg, 195/65-15 tires at 38 psi. 310k miles on the odometer
Took a 3500 mi trip to the east coast & back to TX, avg mpg was w/fully loaded roof rack, a/c on, 70 mph was 27 mpg, best mpg of the trip was 28.5 mpg at 85 mph through the mountains of TN on the return trip, but the roof rack was not loaded.
I've hit 31.5 mpg a few ties unloaded, and regularly get 25 mpg round town.

How did you advance your ignition timing? I thought LH2.4-3.1/EZK automatically sets timing. Did you do the trick where you ground out one of the ECU terminals? I'll have to read up on it!

Yes, EZK grounding 18 & 19 gives about 1.5 deg adv at base idle and ~4-5 deg at WOT

350 mile round trip last night, mix of freeway, state highway, county roads and 20 miles of rock road.

24 mpg. automatic, not running air, 75 on the interstate.

Full throttle on a light change up to speed, significant engine mods, VX cam, all for power, even the ECU has been tweaked to provide more fuel at higher RPMs. Our 92 245 while driving from Herndon, VA to Davie County, NC averaged 24.5 MPG while "flogging" the car from a standing start to near 80MPH 30 mile runs on average down 29 South.

That being said, this is a one of a kind LH 3.1 car with an AW-70 trans with a manual trans rear end ratio.

I have done the "economy" runs in town with starting off slowly and feathering the throttle whenever possible. That results in a 26MPG solution. If I do conservative freeway driving at 65 for hours on end, 30MPG at 65 MPH is easy, going over 65 results in a serious MPG penalty.

If your mileage is in the teens, something is obviously wrong, O2 sensor, MAF sensor, ECU on drugs (heck it happens), and even things like the fuel pressure regulator and coolant temp sensor. Our stock 65 Ford 390 300 HP V8 gets better gas mileage than what you are getting!

jorrell
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92 245 299.3K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

I'm at an advantage since I have a manual tranny and drive like grandpa on the highway (>60 MPH)...

I average in the upper 20s for MPG. I peak in the low 30s on the highway and dip to around 24 MPG in the winter.

A lot of MPG depends on how you drive. When my wife drives her Corolla, she averages in the low 20s. When I drive it - low 30s. But a not-so-efficient Volvo also affects it.
--
Mike F - 1984 244 DL - 306,000 miles
Original engine, transmission, drive train, starter
Undergoing reconstructive surgery with POR-15

1986 245DL Automatic 283K, tropical fan clutch.

Gets 21 to 22 mpg going 72 miles to work and back at speeds from 40 to 70+ mph and the AC running. Very consistent mpg unless my foot gets really heavy.

Just got 24.6 mpg out on the highway at 70 mph with the AC running this last weekend on a 500 mile round trip to visit my daughter.

IF I really watch my speed and run with the AC off in the cooler months, I have gotten as high as 26 to 27 mph.

Regards,

Paul

i have a '89 240 ... getting 22 around town and 24-25 mpg on the highway.
I am going in for a 120k tune up in a month or so.

1987 245. 233,000 5 speed

between September 12, 2007 and September 20, 2010 I drove 44,807 miles. I burned 1470.04 gallons of gas for an average of 30.48 MPG. (I use the Road Trip app on the iPhone. You can export your data to a spreadsheet)

I checked my mileage with GPS and there was a minuscule difference in the mileage--not enough to matter, but enough to drive an OCD person like me nuts. My miles were a couple of hundredths short. Crap! I put the GPS away.

I do the following:

Check Tire Pressure every week
Fill up at the same station, same pump 99% of the time
Always am tuned up with clean throttle body, flame trap, filters, etc
Red line fluids all around. (oil is !0 bucks a quart, but I run it 7500 miles)
I drive 55 and I shift when the little light says shift. (70 on the interstate)
Don't use air (it works and I live in Mississippi)

Dow

1887 245 233,000
2001 XC70 162,000

My best was 32mpg on a long highway trip to Quebec with a five speed and keeping the speeds in the sane range of 65 to 70 mph. Around town I'll routinely get 24.
--
http://www.facebook.com/album.php?aid

Does the car pass emissions OK? This is probably the only way to verify that the O2 sensor is accurate.

Which ECU do you have?

This spring, I replaced the the 1990 245's ECU (pink -561 died in the driveway) with a -951 and replaced the camshaft with an 'A' grind, advanced 2 degrees. Combined with the manual transmission and 2 year old direct fir Bosch O2 sensor, the car gets like nuclear-submarine mileage. 32-34mpg repeatably.

-Ryan

Yes, the car passed CA emissions fine two years ago. It is due again though.

On my 1983, I have kept detailed fuel consumption records, and can say that the single biggest factor is driving style/conditions.

Back in the 55MPH speed limit days (1984) it would pull down 33MP(US)Gallon on the highway. Recently my son followed me 400mi while I was driving a big UHaul towing my MGB on a car transporter and it got 34. We were doing about 50-55MPH and needless to say, there was no fast overtaking or sprinting up hills!

At a steady 65-70MPH it typically gets 29-31. Around the city with a mix of maybe 30% freeway commute, it does 23 or so. These numbers are all corrected for odometer error.

Here's my recipe: clean air filter, Mobil-1 5W30, 34psi in the 195/70-14 Bridgestone Touranza's, fresh set of NGK (BP6ES) every 20k, base timing on spec at 12deg BTC, still on the original O2 sensor at 165k, cleaned and flow tested injectors about 15k ago (with no detectable improvement).

The original Volvo/Chrysler "white cap" distributor and rotor have never been touched. Plug wires were replaced with new Bougicords a few years ago.

Something I have not seen noted here: my full set of 1983 Green Books has the "New Car Features" book, and it speaks to the introduction of the LH 2.0 system and the knock sensor by pointing out that the former allowable maximum valve clearance when "checking" is now tightened up a little to avoid triggering the KS, which then retards ignition timing. Retarded timing will definitely reduce fuel economy. Presumably this applies to all subsequent years.
--
Bob: son's 81-GL, dtr's '94-940, my 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.

I recently went through all the records for my '92 245, and the original dealer sticker claims 35mpg/highway. What would it take to get that kind of mileage? Never driving over 50mph?

'91 245 auto 32psi .. rural 2 lane and town combined 23 mpg

Around 20 or so in town, ~25 or so on highway trips.

16V turbo running E85, Mustang T5 trans with .68 OD and 3.73 OD - 3000 rpm at 80 mph.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)

I'm getting 25 to 26 combo driving with 87 octane gas and 35 psi on my Michelin One radials. Auto trans and a/c on.
--
'86 sedan with 443,000 miles on the original engine and automatic transmission

My 1985 wagon gets a combined 21.5 mpg
--
1993 240, 1992 240GL, 1985 240DL Wagon, 1983 240DL

Back at sea level 21 was good up here at 7200' I average 27-28 No freeways up here so it's mostly all 35-55mph county roads and in town driving.

EDIT: '88 240/B230/AW-70/VX cam/2.5" exhaust/serious suspension mods with 205/65/15 on Virgos driven hard.
--
Dave Shannon
Durango, CO
'67 1800s
'88-240
My Volvo Pages

Hi Dave.
long time.
glad to hear your still rolling that two forty.
hope all is well with you.
regards
Mike

I get about 19 driving around the city, the car rarely sees highway use at all. I suspect my MAF is toast, however, the flapper valve in the airbox is wide open all the time, even on hot summer days. I unhooked the aluminum duct so it wouldn't suck superheated air anymore in the meantime, but I suspect the damage was done.

Replacement thermostat valve and MAF should arrive Monday. I'll post results.

I get close to 30mpg with my 93, but most of my driving is 50 to 60 mph. City driving and 60mph+ takes that way down.

From my experience the O2 sensor is the most important factor. Changing that has sometimes improved my fuel economy at least 25%. After that, tire inflation (I run 38-40psi), and no dragging brakes.

The LH temp sensor can also cause bad fuel economy if it is not working. This can be caused by a ground problem in the wiring harness.

I get 30 on the freeway at 60 mph in my '85 244 M46 with 223K miles....60 mph because I'm in no hurry and it keeps me out of the traffic.
Dukester

What kind of transmission do you have?

I have an 84 without working Overdrive, and I get 24mpg in 4th gear @ 2900rpm on the freway. It's got LH 2.2 I believe.

Happy Bricking
--
1990 740 Turbo, on its way to stock specs, maybe beyond

i do mostly highway cruising in central illinois (read: flat) between 60 and 70 mph, over 200 miles each time. with AC on, i get between 24 and 25 mpg in the summer. 1 mpg extra if i turn AC off. fuel is #89 from either murphy usa or QT. numbers are GPS verified.

edit: '91 245, stock with ignition advanced 2*

my 82 254 with the B21 + LH 1.0 consistently gets 20mpg in the city. At least twice a year I take it on a road trip about 250 miles away. I use less than a tank of gas each way and almost always get 29-30mpg.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0

Wait I thought the B21F MPG engine was k-jet and not LH?

http://www.k-jet.org/articles/information/b21-motor-guide/

Anyway, my '82 k-jet 242 gets similar mileage to H4L's.

Jesse

Yes, it is a confusing year/engine/FI combination. The LH 1.0 system was only on some of the 82 models half way through the model year (As far as I can tell CA cars only?) and was replaced the following year by LH 2.0 and the larger displacement B23.

It's a real PITA trying to find parts for the FI system. The injectors are unique and have special rubber tubing on the end that connects them to the rail. The rail is unique, as are the ECU/control unit and MAF. Among others, there isn't a TPS switch like every other LH system. Also, I get the Cold Start injector and thermal time switch like the k-Jets had.

If you want a laugh, turn to pg 250-5 in your Bentley 240 manual. The picture is of the intake manifold from my engine, with the odd little tubes connecting the injectors to the rail. The funny part is the caption of this image 'TYPICAL intake manifold and throttle body'
--
'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0

Ha!

I used to wish that I had your engine instead of my k-jet, but now I'm glad I don't!

So both the k-jet and the LH 1.0 engines were "MPG" engines?

Jesse

yessir
--
'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0