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Hey all,
On my 89 244dl Im getting about 250-260 miles per 15.7 full tank of gas. That comes out to like 16MPG. Is it just me or is that horrible? I'm not a conservative driver, but from what I've seen others say I should still be getting like 23MPG. Ive got new tires on the car that are at the correct PSI, have recently replaced the spark plugs (3 weeks ago?), and cleaned the throttle body last week.
Only things I think I have left to do are replace spark plug wires, new gaskets for exhaust manifold because I think I have a leak there and find a small leak in my gas tank somewhere. I'm not even sure if the leak is in the gas tank though because there is never enough leaked to leave any spots, just fumes. I have checked the lines in the trunk and they seem fine. The smell comes from the area around the rear right tire if your facing the car from the front.
Does any of that maintenance sound like it should fix the problem for me? What else should I look into?
Thanks!
Trevor
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Alright, ran it till it was in the red. Went and filled it up till click: 12.47 gallons. So with just under 240 miles and about 12.5 gallons thats almost exactly 19MPG. That's much better than I thought. I'm hoping with some maintenance I can get it up to 23-25MPG.
I'm thinking that NGK plugs instead of the platinum Bosche ones I put in a couple weeks, plus new spark plug wires & distrib cap, and a oil/oil filter change will help.
Thanks for your help guys.
Trevor
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I'd toss an O2 sensor on that list if you're unsure of how old the current one is. I've gotten a few mpg's better after replacing mine.
--
'87 Blue 245, NA 214K
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OK..
Last time I filled up my tank I ran it till it was bone dry and couldnt even be started up. I did that because I'm pretty sure my fuel gauge is off by a couple gallons. I got the number 15.7 gallons because thats what a friend told me was the typical gas tank in late 80's 240's.
At this moment I am nearly in the red/orange and I have just over 230 miles. Assuming that's about 14 gallons used that is still only ~16 MPG. The tires were just aligned because I just had them put on and they are at the correct PSI, I checked yesterday. I'm definitely going to take a good look at the FPR, that sounds like it could be the culprit!
Thanks for all the info, and I'll give results after I check the FPR.
Trevor
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The only way to really calculate mileage is to fill the tank, run it down low, record the miles and fill it again to the same point.
In all my years of driving these cars, I've run them to the bottom of the gauge many times, and never put in more that 13.1 gallons. I know what the book says- but I also stop when the pump clicks off. I don't need to fill it until it's coming out the filler neck. I've never heard of anyone actually putting 15+ gallons in one of these cars.
So make sure the figures are accurate and keep a log of it- a notebook in the glovebox listing mileage and gallons is a great record and a really good way to track problems or improvements.
My 86, 87, and wife's 88 all got almost exactly 20 mpg over a long-term average. After a fuel delivery problem, the 86 dropped to 18. Also, they all dropped in cold weather because I warmed them up for quite a while sometimes before going to work. (note that a cold engine uses a lot more fuel- just a low-temp thermostat can hurt your mileage). And all these cars are AW70 automatics. The 5-speed I just acquired already seems to be getting better mileage than any of the others.
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Rob Bareiss, New London CT ::: '87 244DL/M46- 220K, 87 244DL- 230K, 88 744GLE- 198K, 91 244 180K, 88 244GL 145K
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You won't know how much gas you used until you fill the tank to the exact spot this next fill up...any other way is just guessimating at best. (I estimate my red mark starts at about 11 gallons or so plus or minus 2 gallons :)....)
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www.fidalgo.net/~brook4
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Other than what has been suggested, please be sure your "new tires" are the correct size. If they are wrong, your odometer is not giving you correct informaton. Also, please be sure your are figuring your mileage correctly as suggested by a previous post.
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Things that make a difference:
Tire pressure and alignment (more effect than people think)
Of course tuning issues - from clogged cat to dirty injectors to bad spark plugs should all be brought up tp spec.
Automatics are mpg killers in 240's.
How do you get in 15.7 gallons into your tank?
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www.fidalgo.net/~brook4
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Easy!!!
240's have 16.9 gallon tanks or 64 liters if you speak metric. I try not to dip past 14 gals... But I will agree on the automatic thing. Boring and they eat gas.
Richard.
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Dang I know the capacity........I don't think I have ever added more than 14 gallons....it's not that great to run the tank so low.
What do you guys do, whizz along on E for week? :)
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www.fidalgo.net/~brook4
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Don't you know that "E" stands for "e"xtra mileage??? :-)~ Less weight on board...lol
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OK, pls don't be offended, but are you computing your MPG correctly? You are basing it on 15.7 gallons, but that would mean you'd have to drive it bone dry each time you fillup. You should be running it down to about the orange mark on the gas gauge, filling up, and zeroing out the odometer. Then when you run down to the orange mark again, use the amount of gas you added for fillup (10-11 gallons) and use the miles on the odometer for the calculation. It's not a good practice to go below the orange mark on the gas gauge because the in-tank pump depende on the gas for cooling and running it dry shortens its life.
If the above doesn't apply, check the overall state of tune, but pay particular attention to the fuel pressure regulator. It can fail by allowing the pressure to be too high, which will reduce mileage.
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Check the fuel pressure regulator and the vacuum line to it. If the line is loose or the rubber splits, the FPR goes to maximum pressure on the fuel rail. This can lead to gas odors and lower mileage. Pull off the vacuum line and smell for gas fumes. If you smell gas, the FPR is leaking and needs to be repalced. I have one that seems to be starting to do that.
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Note that you will get a bit of a gas smell even if the fpr is good. It should not be wet with gas.
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I think the gas smell in the back is your clue.
The entire fuel system is sealed in the back. The EGR system is in the front of the vehicle and is the only place the system is vented to the outside except for the fill pipe and it is supposed to be sealed.
I would be looking real hard at finding the leak and then checking milage.
Gambit...
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Hello,
Having a lead foot has not typically affected the mileage on my wagon. I have a VX cam, K&N air filter, turbo exhaust and a very heavy foot. Mine will do about 270 miles (420 km) on about 14.5 gals (50 liters) worth of premium fuel. I figure that's in and around 18-20 mpg??? Sometimes it gets better, sometimes not.
Does your brick pick up idle smoothly??? Could be a sign on a bad o2 sensor. Try cleaning out the idle air control valve below the throttle body. Check all the obvious electronic and sensor wiring as well.
One cannot truly expect a 14 year old car to perform up to factory spec no matter how well maintainted it is, especially if you are creeping up over 150,000 miles as well. Hope this helps a little.
Happy Bricking!!!
Richard
87 245 DL 354,000 km
82 242 GLT 121,000 km
http://members.cardomain.com/richink
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