Interested in your findings, as im experiencing very poor mileage too.
O2 sensor obd data
O2 sensor obd data / gas mileage
I don't know why but I've had a feeling for a while that the car has been running richer than it needs to... so i picked up one of those ELM based obd readers and a copy of scanmaster... I did a couple test drives around while pulling data and I guess I want to touch base that what I'm seeing is reasonably normal...
So the average B1S1 O2 sensor reading is .38V (theoretical average should be around .45V when everything is new right?) but that's with a significant number of 0V (zero) readings that tend to come in bunches -- most of them seem to happen when stepping off the accelerator and the system goes into 'open loop' mode... I'm not sure if the reading is really 0V or if the system just reports 0V when entering open loop mode.
Originally I thought it was only supposed to enter OL mode when the throttle is wide open... though it seems it also goes into OL mode when decelerating. Can someone confirm that this is normal?
[edit: removed a blurb asking what typ gas mileage was - found tons of threads on this]
Also short term fuel trim tends to average near 0% and long term near -5%.
(this on a 2000 Celica auto GT gifted 5 months ago currently just under 130k km)
EDIT: just took it out for another spin with the mpg gage open on the scanmaster software... never topped 12mpg on the highway except when accelerating where it increased (not what I expected) so something is very wrong.
Q: what are typical MAFS readings at ~2900 RPM / 74 miles/hour?
I don't know why but I've had a feeling for a while that the car has been running richer than it needs to... so i picked up one of those ELM based obd readers and a copy of scanmaster... I did a couple test drives around while pulling data and I guess I want to touch base that what I'm seeing is reasonably normal...
So the average B1S1 O2 sensor reading is .38V (theoretical average should be around .45V when everything is new right?) but that's with a significant number of 0V (zero) readings that tend to come in bunches -- most of them seem to happen when stepping off the accelerator and the system goes into 'open loop' mode... I'm not sure if the reading is really 0V or if the system just reports 0V when entering open loop mode.
Originally I thought it was only supposed to enter OL mode when the throttle is wide open... though it seems it also goes into OL mode when decelerating. Can someone confirm that this is normal?
[edit: removed a blurb asking what typ gas mileage was - found tons of threads on this]
Also short term fuel trim tends to average near 0% and long term near -5%.
(this on a 2000 Celica auto GT gifted 5 months ago currently just under 130k km)
EDIT: just took it out for another spin with the mpg gage open on the scanmaster software... never topped 12mpg on the highway except when accelerating where it increased (not what I expected) so something is very wrong.
Q: what are typical MAFS readings at ~2900 RPM / 74 miles/hour?
1 - 9 of 9 Posts
FYI: the MPG I got was from the OBD reader software... I've queried the authors of the software how it calculates the fuel flow rate (this on the surface cant be queried via obd directly)... This week I'm 'manually' tracking my fuel use to confirm the numbers.
During deceleration the ecm overrides closed loop and decreases injector pulse using maf and tps readingsOriginally I thought it was only supposed to enter OL mode when the throttle is wide open... though it seems it also goes into OL mode when decelerating. Can someone confirm that this is normal?
Correct, thats what i have been told.So the average B1S1 O2 sensor reading is .38V (theoretical average should be around .45V when everything is new right?)
Try cleaning maf and retesting if you havent already.
tps readings? temperature & pressure?
Haven't cleaned the mafs yet... I'll probably get around to it tomorrow-ish
Anyway a bit of a follow-up: after doing the mpg the proper way I'm finding I'm getting pretty good mileage at least highway driving: 31mpg on a trip to montreal and 28mpg on the way back + a few days of city driving. So that's all clear...
... now all I want to figure out is why the obd software reports such high usage. Oh and hopefully get the O2 sensor readings a little closer to ideal (.45).
Haven't cleaned the mafs yet... I'll probably get around to it tomorrow-ish
Anyway a bit of a follow-up: after doing the mpg the proper way I'm finding I'm getting pretty good mileage at least highway driving: 31mpg on a trip to montreal and 28mpg on the way back + a few days of city driving. So that's all clear...
... now all I want to figure out is why the obd software reports such high usage. Oh and hopefully get the O2 sensor readings a little closer to ideal (.45).
It's still in closed loop on decel..
tps readings? temperature & pressure?
TPS= throttle position sensor located on the throttle body (3 wires).
TPS= throttle position sensor located on the throttle body (3 wires).
so (to recap)... under normal driving what would cause the system to go to open loop? (or at least report that it has left closed loop?)
open loop, cold start up till o2 above 600 f, coolant temp above 150 f, also more than 80% throttle (acceleration mode), also deceleration mode ( decrease in maf and tps ). Also cel light on is safe mode, much like open loop.
1 - 9 of 9 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
NewCelica.org Forum
A forum community dedicated to all 7th Generation Toyota Celica owners and enthusiasts. Come join the discussion about modifications, troubleshooting, engine swaps, maintenance, and more!
Full Forum Listing
Explore Our Forums
Recommended Communities
