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""When adding the long term trim to the short term trim, you obtain a basic “total trim number”.
This number should be very close to zero, never exceeding 10% positive or negative.""......Link
They also state to not use a Honda specific, but a global reading.
They list several factors also to look at when obtaining numbers.
I think I'll look at it again later on just the OBD2 side and at operating temp.
I will do a idle and 2500 rpm reading for comparison.
According to them, my total trim is out since it shouldn't exceed 10% even though everything is running good and no codes, but I was using Honda and not global and I don't recall if engine temp, etc were proper.
Short 1 (9.4) + long 1 (10.2) = 19.6
Short 2 (7.8) + long 2 (7.8) = 15.6
The need for knowledge/understanding grows....lol.
This number should be very close to zero, never exceeding 10% positive or negative.""......Link
They also state to not use a Honda specific, but a global reading.
They list several factors also to look at when obtaining numbers.
I think I'll look at it again later on just the OBD2 side and at operating temp.
I will do a idle and 2500 rpm reading for comparison.
According to them, my total trim is out since it shouldn't exceed 10% even though everything is running good and no codes, but I was using Honda and not global and I don't recall if engine temp, etc were proper.
Short 1 (9.4) + long 1 (10.2) = 19.6
Short 2 (7.8) + long 2 (7.8) = 15.6
The need for knowledge/understanding grows....lol.
Looking at the 09'-12' FSM, it shows a good Short Term Fuel Trim of 0.81 - 1.23
I wonder if this is the lambda value or actual short term reading.
Anyone know?
.
I wonder if this is the lambda value or actual short term reading.
Anyone know?
.
Attachments
While trying to figure out my fuel trims, I noticed the cat temps.
When I saw the high temps on the 15765-4 protocol, I jumped over to the Honda side and get a different number.
1000* cat temp just about flipped me out, but the 547* is more believable.
Both temperature readings taken close to the same time during live data stream.
One on the OBD2 side, other on the Honda side.
On OBD2 Side, protocol ISO 15765-4 CAN (29 bit)
Catalyst Temp Bank 1 sensor 1 .. 1075*F
Catalyst Temp Bank 2 sensor 1 .. 1075*F
On Honda side of scanner, it just shows protocol '(CAN)'
Catalyst Temp Bank 1 sensor 1 .. 547*F
Catalyst Temp Bank 2 sensor 1 .. 547*F
The same for fuel trims.
OBD2 15765-4
Short 1 (9.4) + long 1 (10.2) = 19.6
Short 2 (7.8) + long 2 (7.8) = 15.6
Honda Side.
Short Term Fuel Trim (lambda) 1.000
Short Term Fuel Trim Bank 1 ... 1.009
Short Term Fuel Trim Bank 2 ... 1.009
The OBD2 side shows I have a lean condition while Honda side shows I'm good
The cat temp difference is still bugging me.
Truck is a 09' with 40k miles, no codes showing, runs great and average 18.5 - 19.5 in mixed driving.
What I'm I failing to understand here?
Anyone have a clue or would this be better suited on one of the VTEC/J series forums.
When I saw the high temps on the 15765-4 protocol, I jumped over to the Honda side and get a different number.
1000* cat temp just about flipped me out, but the 547* is more believable.
Both temperature readings taken close to the same time during live data stream.
One on the OBD2 side, other on the Honda side.
On OBD2 Side, protocol ISO 15765-4 CAN (29 bit)
Catalyst Temp Bank 1 sensor 1 .. 1075*F
Catalyst Temp Bank 2 sensor 1 .. 1075*F
On Honda side of scanner, it just shows protocol '(CAN)'
Catalyst Temp Bank 1 sensor 1 .. 547*F
Catalyst Temp Bank 2 sensor 1 .. 547*F
The same for fuel trims.
OBD2 15765-4
Short 1 (9.4) + long 1 (10.2) = 19.6
Short 2 (7.8) + long 2 (7.8) = 15.6
Honda Side.
Short Term Fuel Trim (lambda) 1.000
Short Term Fuel Trim Bank 1 ... 1.009
Short Term Fuel Trim Bank 2 ... 1.009
The OBD2 side shows I have a lean condition while Honda side shows I'm good
The cat temp difference is still bugging me.
Truck is a 09' with 40k miles, no codes showing, runs great and average 18.5 - 19.5 in mixed driving.
What I'm I failing to understand here?
Anyone have a clue or would this be better suited on one of the VTEC/J series forums.
Well, 1075F = 579C which isn't too far off. Maybe one is labeled wrong. It would make sense that if the Honda side was in Celsius. I notised they used KPa vs PSI, so the "international" units seem to be in play.
Well, 1075F = 579C which isn't too far off. Maybe one is labeled wrong. It would make sense that if the Honda side was in Celsius. I noticed they used KPa vs PSI, so the "international" units seem to be in play. I also remember that Cats are VERY hot (more than mufflers).... I just don't recall how hot.
Skelly,
I don't know much about the Honda numbers vs the OBDII numbers. That said here are some thoughts on your fuel trim % numbers:
Don't worry about the bank 3 and bank 4 stuff. Our trucks only of Bank 1 and Bank 2
The trim numbers don't really mean much until your vehicle is at operating temp. Make absolutely sure that your truck is FULLY warmed up before you concern yourself over the %s. I would suggest you take your truck out for a nice long ride including stop and go stuff as well as steady 50mph+ cruising. Examine your trims during this drive.
I read the same article talking about the combination numbers of short term trims ans long term trims but I can't make too much sense of it. Short term trims will always vary and they do sometimes spike up well over +-10/15%. Best as I can tell, this is normal. It may make some sense if you are seeing a CONSISTENT situation where the trims total more than 10% on the + or - sides.
If you find that your Long term fuel trims (LTFT) are consistently over 10% in one or both banks then you probably do have something less than optimal with your truck or the gasoline that is in the tank. If your fully warmed up truck has elevated + long term trims at idle, but the short trims go solidly negative when you increase the RPMs (while in park) then you may well have some small vacuum leak. If STFT's increase as you increase RPM then look to fuel delivery (injector issues, fuel filter, fuel pump etc etc.
10% ethanol gas probably has an effect on long term fuel trims. In the DC area, I can't get anything but E10 without driving a million miles and paying stupid money. I wouldn't be surprised to see as much as a 5% increase in LTFTs as a result of it (and other winter blend additives) on our truck.
Keeping things in perspective, your truck seems to be running reasonably well (my trim number are "better" than yours but am averaging between 14 and 15mpg right now in the driving that I do!) The trims on your truck are also in the controllable range (your mixture is fine)
If someone else out there wants to share their Ridge's LTFT behaviors (preferably from an 09+) it would be very useful to compare to your truck.
PS: My truck also has a similar difference between LTFTs for bank 1 and 2. My bank 2 numbers are a typically a couple of % points lower (closer to zero). It may well be the nature of the plumbing for our trucks.
I don't know much about the Honda numbers vs the OBDII numbers. That said here are some thoughts on your fuel trim % numbers:
Don't worry about the bank 3 and bank 4 stuff. Our trucks only of Bank 1 and Bank 2
The trim numbers don't really mean much until your vehicle is at operating temp. Make absolutely sure that your truck is FULLY warmed up before you concern yourself over the %s. I would suggest you take your truck out for a nice long ride including stop and go stuff as well as steady 50mph+ cruising. Examine your trims during this drive.
I read the same article talking about the combination numbers of short term trims ans long term trims but I can't make too much sense of it. Short term trims will always vary and they do sometimes spike up well over +-10/15%. Best as I can tell, this is normal. It may make some sense if you are seeing a CONSISTENT situation where the trims total more than 10% on the + or - sides.
If you find that your Long term fuel trims (LTFT) are consistently over 10% in one or both banks then you probably do have something less than optimal with your truck or the gasoline that is in the tank. If your fully warmed up truck has elevated + long term trims at idle, but the short trims go solidly negative when you increase the RPMs (while in park) then you may well have some small vacuum leak. If STFT's increase as you increase RPM then look to fuel delivery (injector issues, fuel filter, fuel pump etc etc.
10% ethanol gas probably has an effect on long term fuel trims. In the DC area, I can't get anything but E10 without driving a million miles and paying stupid money. I wouldn't be surprised to see as much as a 5% increase in LTFTs as a result of it (and other winter blend additives) on our truck.
Keeping things in perspective, your truck seems to be running reasonably well (my trim number are "better" than yours but am averaging between 14 and 15mpg right now in the driving that I do!) The trims on your truck are also in the controllable range (your mixture is fine)
If someone else out there wants to share their Ridge's LTFT behaviors (preferably from an 09+) it would be very useful to compare to your truck.
PS: My truck also has a similar difference between LTFTs for bank 1 and 2. My bank 2 numbers are a typically a couple of % points lower (closer to zero). It may well be the nature of the plumbing for our trucks.
Convertors don't really operate well until they are at least 400F and can heat up to 1600f and beyond. Typically, the cleaner the vehicle is running the lower the number. I do think that his Honda number must be in C. There is no reason to think that the OBD data is incorrect while the Honda is correct. Its just that the Honda number should have a C after it while the OBD # correctly has an F.
Yes you guys are correct, I double checked and it did switch back to *C, nice catch!
In my haste to gather data I made the error mentally....duh!
I also verified the ST fuel trim readings and they are 1.09 and not 1.009
When I get some time this weekend I will get the wife to drive and get some data at a constant speed.
I think if I can gather more data, it might make more sense to me.
Still learning here and thanks for catching my error, my head was about to explode.....lol.
In my haste to gather data I made the error mentally....duh!
I also verified the ST fuel trim readings and they are 1.09 and not 1.009
When I get some time this weekend I will get the wife to drive and get some data at a constant speed.
I think if I can gather more data, it might make more sense to me.
Still learning here and thanks for catching my error, my head was about to explode.....lol.
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