Closed and open loop, mpg
#1
Closed and open loop, mpg
I'm curious does anyone have a ball park figure or guess on fuel consumption in closed loop vs open loop operation or a link? This would be a 93 V6 auto operating in warm weather.
I do not see a clear answer on the net.
I do not see a clear answer on the net.
#2
Registered User
An Auto in Closed loop ought to give better than 17MPG highway in ordinary conditions.
My manual tranny '95 Runner with 4.56 gears and 32 inch tires gives about 19.5 MPG at 60mph and it drops to near 18MPG @ 70 to 75mph.
What are your issues?? A professional scanner with period software can tell whether you're in closed loop, or not.
My manual tranny '95 Runner with 4.56 gears and 32 inch tires gives about 19.5 MPG at 60mph and it drops to near 18MPG @ 70 to 75mph.
What are your issues?? A professional scanner with period software can tell whether you're in closed loop, or not.
#3
Some of us on the Toyota RV forum are having poor mpg issues. I'm reading a bit and find info on closed and open loop. But do not see any actual percentages or anything solid. I appreciate the 17 mpg but no one with a V6 auto RV are getting anywhere near that. Maybe the consumption between rich and lean is negligible and not an issue?
I have read at least 30 articles and seen only one number published claiming a 20% difference.
I have read at least 30 articles and seen only one number published claiming a 20% difference.
#4
Registered User
Some of us on the Toyota RV forum are having poor mpg issues. I'm reading a bit and find info on closed and open loop. But do not see any actual percentages or anything solid. I appreciate the 17 mpg but no one with a V6 auto RV are getting anywhere near that. Maybe the consumption between rich and lean is negligible and not an issue?
I have read at least 30 articles and seen only one number published claiming a 20% difference.
I have read at least 30 articles and seen only one number published claiming a 20% difference.
A pro scanner and a wide band O2 sensor can still help ya.
Last edited by millball; 09-24-2018 at 11:54 AM.
#6
Registered User
I would think that the difference between open loop and closed loop would change depending on how close the pre-programmed values and fuel "map" for open loop operation in the ECU matched to the actual operating conditions.
A closed loop system should perform better and get better mileage than open loop.
What fuel mileage numbers are you getting?
Are you thinking that the engine is not going into closed loop?
A closed loop system should perform better and get better mileage than open loop.
What fuel mileage numbers are you getting?
Are you thinking that the engine is not going into closed loop?
#7
Long story, I do not tract my mpg but recently had a drop so significant that it was hard to miss, so checked my mpg. Only a couple tanks and varied driving so not a good mileage check but I was getting over 10 mpg. On a trip so I diagnosed as best I could and replaced the fan clutch. Again only a couple tanks and mpg seemed to be 10 to 11. But I started having issues with transmission not wanting to go into overdrive.
Took to Aamco transmission in Macon GA and they could find nothing wrong. Claimed transmission was in excellent condition, so I was not afraid to continue my trip home.
Started reading about poor mpg and learned a few things. Also figured out my motor was running around 165 degrees on a 93 degree day. Also read about this closed and open loop and wondering if this fits in someplace?
Did not like the way the aftermarket fan clutch operated so returned and replaced with an Aisin. The thermostat tested good, but I was not sure if it was OE so replaced with an OE Toyota stat. Engine is now running around 180 on a 20 mile drive and motor sounds much better. I am checking motor with a temp gun right after driving on highway. Do not drive the RV alot so will be some time before I can do a road test for mpg.
There are a few on the Toyota RV Face Book page that are experiencing poor mileage so hoping to find something that has been over looked. One owner could not get over 10 out of his V6 so got disgusted and sold it! 12 to 13 seems to be average mileage with some drivers claiming to be able to do 14. I would be happy with the 12-13.
So anyway curious about the open loop/closed loop and how much it affects mpg?
Took to Aamco transmission in Macon GA and they could find nothing wrong. Claimed transmission was in excellent condition, so I was not afraid to continue my trip home.
Started reading about poor mpg and learned a few things. Also figured out my motor was running around 165 degrees on a 93 degree day. Also read about this closed and open loop and wondering if this fits in someplace?
Did not like the way the aftermarket fan clutch operated so returned and replaced with an Aisin. The thermostat tested good, but I was not sure if it was OE so replaced with an OE Toyota stat. Engine is now running around 180 on a 20 mile drive and motor sounds much better. I am checking motor with a temp gun right after driving on highway. Do not drive the RV alot so will be some time before I can do a road test for mpg.
There are a few on the Toyota RV Face Book page that are experiencing poor mileage so hoping to find something that has been over looked. One owner could not get over 10 out of his V6 so got disgusted and sold it! 12 to 13 seems to be average mileage with some drivers claiming to be able to do 14. I would be happy with the 12-13.
So anyway curious about the open loop/closed loop and how much it affects mpg?
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#8
Registered User
I would say the 20% difference is pretty a accurate bu that is merely a guess. The engine running around 165 is what was causing your transmission troubles. The ecu will not allow the transmission to go into over drive until it is up to temperature. I want to say they did this to warm the engine up faster for emissions.
#9
I would say the 20% difference is pretty a accurate bu that is merely a guess. The engine running around 165 is what was causing your transmission troubles. The ecu will not allow the transmission to go into over drive until it is up to temperature. I want to say they did this to warm the engine up faster for emissions.
Next on the mental list if I get no improvement is the O2 sensor. I believe mine is OE with 115000 on it. Many claim they should be replaced over a 100K??
#10
Registered User
Yes, changing the oxygen sensor would help. Its a maintenance item. The sacrifice of more $$ at the pump is a usual sign. Just over 100k is pretty good usage on them. Maybe ask those who are getting higher mpg while using their RVs if they are using wide band sensors to give you an idea of whether you should go that route.
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jjrbus (09-27-2018)
#11
Yes, changing the oxygen sensor would help. Its a maintenance item. The sacrifice of more $$ at the pump is a usual sign. Just over 100k is pretty good usage on them. Maybe ask those who are getting higher mpg while using their RVs if they are using wide band sensors to give you an idea of whether you should go that route.
#12
Registered User
It is installed separately and sends a signal to a gauge that reads out a display of real time fuel/air ratio.
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