Mileage has gone to hell after transmission rebuild
07-17-2013, 10:34 AM
#11
Foghorn Leghorn
Thread Starter
Join Date: Dec 2006
Location: I reside in a near constant state of amazment.
Posts: 2,923
When I had it rebuilt I asked for it to be rebuilt to stock specifications. As far as I can tell the shift points haven't changed at all either upshifting or downshifting.
07-17-2013, 01:01 PM
#12
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Are there any exhaust leaks before or near the front O2 sensors? That and/or failing front sensors will make the PCM think the engine is running lean, it will then force the mix richer--up to 25% richer until a DTC is thrown. Check the AFR with a wideband O2 system to see what the mix really is...
07-17-2013, 10:04 PM
#14
2nd Gear Member
Join Date: Apr 2008
Location:
Posts: 228
Proper tire inflation is worth 3 MPG on a Mustang? Really? You couldn't spend .0756 seconds Googling before attributing a 20% MPG loss to tire inflation?
According to Goodyear a 10 psi drop in air pressure on commercial vehicles is worth ONE PERCENT LOSS IN MPG. That's on 80,000 lbs. trucks with 18 low tires. To get a 20% MPG loss on a Mustang, you'd have to drive over a spike strip while being chased by a police helicopter, then the wheels would have to fall off.
http://www.goodyear.com/cfmx/web/cor...y.cfm?a_id=861
According to Goodyear a 10 psi drop in air pressure on commercial vehicles is worth ONE PERCENT LOSS IN MPG. That's on 80,000 lbs. trucks with 18 low tires. To get a 20% MPG loss on a Mustang, you'd have to drive over a spike strip while being chased by a police helicopter, then the wheels would have to fall off.
http://www.goodyear.com/cfmx/web/cor...y.cfm?a_id=861
Also that's amusing as hell fastbackford351. Did they change the torque converter? Little bit more or less stall might cause a problem.
07-18-2013, 01:21 AM
#15
Banned
Join Date: Feb 2013
Location: USA
Posts: 545
If you read that correctly it stated 1% per 10 psi per tire. so if all 18 imaginary tires are 10 psi low what is our theoretical loss in mpg? Regardless comparing commercial grade truck tires to passenger car tires is moot in that the number of ply in the tires will drastically alter the rolling resistance when low on pressure.
You read it incorrectly. Nowhere in that article does it state 1% MPG loss per 10 lbs. per tire.
Last edited by Sonic Mustang; 07-18-2013 at 01:26 AM.
07-22-2013, 09:49 AM
#18
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Proper tire inflation is worth 3 MPG on a Mustang? Really? You couldn't spend .0756 seconds Googling before attributing a 20% MPG loss to tire inflation?
According to Goodyear a 10 psi drop in air pressure on commercial vehicles is worth ONE PERCENT LOSS IN MPG. That's on 80,000 lbs. trucks with 18 low tires. To get a 20% MPG loss on a Mustang, you'd have to drive over a spike strip while being chased by a police helicopter, then the wheels would have to fall off.
http://www.goodyear.com/cfmx/web/cor...y.cfm?a_id=861
According to Goodyear a 10 psi drop in air pressure on commercial vehicles is worth ONE PERCENT LOSS IN MPG. That's on 80,000 lbs. trucks with 18 low tires. To get a 20% MPG loss on a Mustang, you'd have to drive over a spike strip while being chased by a police helicopter, then the wheels would have to fall off.
http://www.goodyear.com/cfmx/web/cor...y.cfm?a_id=861
Average of .4% loss in mpg per psi on a passenger tire. So 10psi on one tire is 4% loss of mpg, x4 = 16% loss.
Now to compare the same 10psi on a commercial truck tire to a passenger tire is completely ridiculous considering that the volume of air is much greater than that of a small passenger vehicle tire. PER SQUARE INCH so knowing that a commercial truck tire has a far greater voulume in sq inches the volume 10psi is much greater than that of a passenger vehicle. there for resulting in in a greater loss of mpg for per every 10 psi for your average tire on a car.
Commercial truck tires hold close to anywhere from 100 to 150 psi
In reality a commercial truck tire can loose 10 psi of air and you would never see it by looking at the tire. For this reason truck drivers check tire pressure far more often or even have built in air pressure gauges on the rims . Removing 10 psi from a passage vehicle tire would be quite obvious.
Its not rocket surgery.
07-22-2013, 02:33 PM
#20
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
good grief people...
http://www.fueleconomy.gov/feg/maintain.shtml 3.3% for under inflation of 10 PSI on a passenger car...
Commercial vehicles are totally different.
Anyways Fastbackford, I would check the O2 sensors as suggested by cliffyk, even the gov site recognizes that as the biggest factor in MPG.
Did you remove or disconnect the O2 sensors for the tranny service?
http://www.fueleconomy.gov/feg/maintain.shtml 3.3% for under inflation of 10 PSI on a passenger car...
Commercial vehicles are totally different.
Anyways Fastbackford, I would check the O2 sensors as suggested by cliffyk, even the gov site recognizes that as the biggest factor in MPG.
Did you remove or disconnect the O2 sensors for the tranny service?