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Paul T. Schram (Paulschram)
| | Posted on Thursday, January 23, 2003 - 12:38 pm: | 
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OK, I know these aren't exactly economy vehicles. My mileage prior to blowing up the top end of the engine was about 15 mpg. After having the heads reworked the truck runs OK, but the mileage has fallen to about 11 mpg. Others who live in my household (SWMBO) are beginning to suggest that a vehicle with better fuel economy might be a better choice than the Discovery...
Shortly after rebuilding the top end, I began to get code 14s on the diagnostic readout, so I replaced the coolant temp sensor. The mileage improved to about 13 mpg, better, but not great. Also replaced the plugs, no dice. Cap, rotor, wires, not that old and certainly not ready to be replaced.
Anybody got another idea for me to work on?
Peace,
Paul |
ema
| | Posted on Thursday, January 23, 2003 - 12:50 pm: |
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Paul,
Is it possible that your original gas mileage calculations were done during the summer? I know in parts of the US (particularly the northeast), oxygenated gasoline is sold during the winter months. That might be enough to account for a 1-2 mpg difference.
Also, any chance your tires were more inflated in the summer than winter?
I'm averaging about 11 mpg with my Disco at the moment. Stop-and-go traffic is mostly to blame, though.
-ema |
Paul T. Schram (Paulschram)
| | Posted on Thursday, January 23, 2003 - 02:19 pm: |
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Ema:
I drive 50 miles to work each day, highway all the way. The mileage calcs were done on a continuous basis. The only change was the head job. I live in an area that does not have a ground level ozone problem and consequently, we are not forced to change to oxygenates-yet!
I'm contemplating replacing the fuel temp sensor, but don't wish to spend the near $100 for something that is not giving the computer inconsistent outputs like the CTS was.
Peace,
Paul |
Robert Sublett (Rubisco98)
| | Posted on Thursday, January 23, 2003 - 02:50 pm: |
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I've not gotten much better than 14 in a long time. Got 17 mpg avg yesterday, it surprised me at the pump this morning Later.. Rob |
M. K. Watson (Lrover94)
| | Posted on Thursday, January 23, 2003 - 07:01 pm: |
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after replacing my stock gears with the GBR 4.11s my gas mileage has jumped to nearly 20 MPG, unbelievable but true. or it could have been the new southdown front skidplate causing my front end to be more areodyanmic. anyways its great.....
for those who don't know me that is satire. i realize that not only did the 4.11 help my engine response after adding the 32.5" tires but it also thru my speedo off 10 mph, so in all reality, my mileage didn't change, a steady 12mpg.
mike w |
Ron
| | Posted on Thursday, January 23, 2003 - 08:37 pm: |
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Normally a drop off in mileage on a 94-95 would be associated with a sensor or ignition failure of some sorts, however, since you just did the heads I am willing to bet you screwed something up. Whats your compression? Maybe a valve is not lapped in properly? No codes? Did you take the dizzy out? If so is it timed properly?
Ron |
Paul Long
| | Posted on Friday, January 24, 2003 - 09:03 am: |
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Spark plug color should show any rich condition. Do you still have the original plugs before the head job to compare the tip color of the plugs now? Vacuum leaks from disturbing any components when doing the heads? Since that's when mileage changed, time to go over everthing that was touched.... After a drive feel wheels for any undo warming. This may show a brake not releasing fully?. Getting fuel from the same pump? I'm sure a local station around me sometimes has 89 octane in their 93 tank! Truck turns gutless. Mileage drops. Always push 18 to 20 on stock 99' D2. I also get "lean bank 1 & 2" codes on decell sometimes. |
muskyman
| | Posted on Friday, January 24, 2003 - 11:01 am: |
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i think Paul did everthing right
i think the fuel he is running is the culprit
he lives near me and the fuel here in the area around lake migh mostly come thru the same 4 fuel depots and because about 70% of the area requires air-management fuel chances are thats the problem
my 94 will get about 15mpg on fuel in northern Wis
the shit down here I get 11mpg maybe 12 tops |
John Cinquegrana (Johnc)
| | Posted on Friday, January 24, 2003 - 11:27 am: |
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I am having the same problem on both the RR and the D1. Usually I would get 250 miles per full tank on the RR and 275 miles on the D1. The RR has two new O2 sensors (4 months old). The weather has changed alot in the last couple of weeks here in the NE. I always fill up at the same station unless of course I am out of town.
Paul, just an FYI my mileage stayed the same after I did the heads on my RR (with help from George S) and everyone knows what a fuck up I am, so if I did it right than you must've done your right... |
Peter Matusov (Pmatusov)
| | Posted on Friday, January 24, 2003 - 11:45 am: |
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Paul, i think your previous gas mileage experience was based on imperial gallons. Or your odometer just flipped to nautical miles
peter |
Paul T. Schram (Paulschram)
| | Posted on Friday, January 24, 2003 - 11:51 am: |
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Peter:
Your comment reminds me of the chapter in my quantitative analytical chemistry text on ion selective electrodes where they referenced the color of one's socks and phases of the moon as interfering agents!
I'll see if switching to better gas and adding a can of voodoo juice does me any good.
Thanx for the comments, compliments, insults(:-)), etc.
Maybe it's time to finish the '67?
Peace,
Paul |
Peter Matusov (Pmatusov)
| | Posted on Friday, January 24, 2003 - 03:47 pm: |
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what '67?
peter |
Geoff 93 RRC (Geoff)
| | Posted on Friday, January 24, 2003 - 04:37 pm: |
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I vote for the winter fuel being the culprit. I have seen my mileage definately drop.
Also, on a '94-'95 the timing is adjustable. You might check that it is in specs especially if the distributor was disturbed when the heads were done. Mileage can definately be affected. |
M. K. Watson (Lrover94)
| | Posted on Friday, January 24, 2003 - 09:35 pm: |
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just a quick question that is sorta related to this topic, the obd indicator (the lil box with all the codes) on the 94-95 disco how does it function? does it recieve a signal once the engine is started, if not when and does it store the error code or does it disappear after a period of time. thanks
mike w |
Jason Vance (Jason)
| | Posted on Saturday, January 25, 2003 - 03:07 am: |
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Hmmm...if a code is tripping (like an 02 sensor), the error code should be displayed while the engine is running and for an additional 5-8 seconds after the engine is turned off (I haven't checked this on my Disco, but it works this way on my RRC which uses an EFI system out of a '90 RRC...same system I believe). |
M. K. Watson (Lrover94)
| | Posted on Saturday, January 25, 2003 - 06:18 am: |
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thanks jason.
mike w |
Scott (Scott_Bowden)
| | Posted on Saturday, January 25, 2003 - 10:31 am: |
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The "joykills" will use any reason to separate a happy person from thier joy.
I think you should replace your thermostat if you havent done so. These trucks like an accurate temp.
If you like your truck, don't talk about mileage. Just smile when you are at the pump and make comments like, this is a small price to pay for such a great truck.
As long as the price increments are the same between the grades of gas, I only look at the price of the low grade and pump the premium. I could tell a mileage difference when I used low and mid grade years ago. That solved that episode of penny pinching.
If I wanted a joyless people mover I would get one of those bland, indescript, little four door cars. |
Christian Frezza (Christian)
| | Posted on Sunday, January 26, 2003 - 11:21 am: |
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Speaking of gas mileage...I'm running a set of 265/75 R16 BFGoodrich A/T KO's. What pressures are best for these tires for everyday use on a DII? Should they be equal or low/high from front to back like tire recommendation inflation pressures in the manual? Help...I'm getting 10/11mpg highway/city...
Thanks |
M. K. Watson (Lrover94)
| | Posted on Sunday, January 26, 2003 - 04:30 pm: |
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great Scott.....good point and thanks!
mike w |
streak
| | Posted on Monday, January 27, 2003 - 11:56 am: |
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Paul,
It's unlikely that your timing suddenly went out but have you checked it, specially since the rebuild?
We used to run our D1 at about 4 to 5 degress higher than the factory spec. 6 degrees. Yes we got a lot more oomph at this altitude (6000 feet) but the consumption also went up.
Also, as others have said check the colour of the plugs, maybe the temp. range is out?
Just a thought??
www.worst4x4.freeservers.com |
Paul T. Schram (Paulschram)
| | Posted on Monday, January 27, 2003 - 12:14 pm: |
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Thanx Streak. I have reset the timing in the past after removing the distributor to reattach the advance can that had become loose, resulting in a tow truck ride. I found that when the timing was set by ear that it was way too far advanced and the fuel mileage went away completely (had what seemed like much more power, but knocked to beat the band). As soon as we go positive on temps again (ambient), I'll confirm it is still within specs, or at least close.
Scott:
The thermostat was replaced last summer while I was avoiding doing the radiator job ($$$). It has a 180' t-stat. Given the operating conditions, I doubt it is stuck in either position. The t-stat removed was apparently working as there was no change with the new one. Yes, I used a SBC gasket and t-stat! I agree that optimum operation of the fuel injection system requires control over all parameters of engine operation and loss of any one (or if it falls out of control parameters, gotta love Sigma!) will cause performance losses.
When I replaced the plugs the day before I replaced the CTS, the plugs definitely showed evidence of a rich condition. I haven't pulled the new ones to see if this has improved.
Peter, the '67 is my wife's Series IIA I'm working on. Something tells me the gas mileage would be somewhat better, regardless of all of the things that will not remain constant. |
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