LTFTs are 0 after switching back to 93 from e85
Jun 28, 2016, 07:19 AM
#1
LTFTs are 0 after switching back to 93 from e85
Hi evo friends! I come to you for advice and hopefully I can find the golden nuggets if information that I'm looking for.
Back story: 2003, mostly stock, 1120cc injectors and 255 pump, stock motor / turbo, 3" exhaust, grimmspeed boost controller, omni power map sensor, got the car tuned on e85 by a VERY reputable shop. When I got the car back, it felt GREAT. ALL OF THE POWERS! However the shop recommended that every few tanks I fill up with 93 because e85 doesn't have any cleaning detergents and the 93 octane will help keep the fuel system clean. I was informed to increase the injector scaling value by about 25-30% to accomodate the 93 which is what I expected to do.
So last week I fill up with 93 and change the injectors from 713 to like 900 or so. The car starts and idles, so I drive home. Then I start noticing it idles rich and cruises rich at low throttle so I start logging only to see all LTFTs are 0. STFT moves around and front o2 sensor voltage moves so I don't think the front o2 is dead. I kept increasing the injector scaling value and its now at about 1044. It seems better, but fuel trims are still 0. The car drives ok, it doesn't stall or stutter or anything, but the AFRs are all over the place. If I stop at a light, it will usually be rich, like 12.0 or so and slowly creep up to 14.7. If I tap the gas, it runs full rich and then back. So getting it moving takes a little finesse. While cruising the AFRs struggle to find stoic. They will run rich to like 12-13, then lean to 15 - 15.5 and back and forth.
I'm not sure what's going on here or what to look for. I've attached my log from my ride to work this morning along with both my e85 tune from the shop and my tweaked 93 octane tune. I've only changed the injector scaling for the 93 octane tune.
Back story: 2003, mostly stock, 1120cc injectors and 255 pump, stock motor / turbo, 3" exhaust, grimmspeed boost controller, omni power map sensor, got the car tuned on e85 by a VERY reputable shop. When I got the car back, it felt GREAT. ALL OF THE POWERS! However the shop recommended that every few tanks I fill up with 93 because e85 doesn't have any cleaning detergents and the 93 octane will help keep the fuel system clean. I was informed to increase the injector scaling value by about 25-30% to accomodate the 93 which is what I expected to do.
So last week I fill up with 93 and change the injectors from 713 to like 900 or so. The car starts and idles, so I drive home. Then I start noticing it idles rich and cruises rich at low throttle so I start logging only to see all LTFTs are 0. STFT moves around and front o2 sensor voltage moves so I don't think the front o2 is dead. I kept increasing the injector scaling value and its now at about 1044. It seems better, but fuel trims are still 0. The car drives ok, it doesn't stall or stutter or anything, but the AFRs are all over the place. If I stop at a light, it will usually be rich, like 12.0 or so and slowly creep up to 14.7. If I tap the gas, it runs full rich and then back. So getting it moving takes a little finesse. While cruising the AFRs struggle to find stoic. They will run rich to like 12-13, then lean to 15 - 15.5 and back and forth.
I'm not sure what's going on here or what to look for. I've attached my log from my ride to work this morning along with both my e85 tune from the shop and my tweaked 93 octane tune. I've only changed the injector scaling for the 93 octane tune.
Last edited by turbotaloon95; Jul 2, 2016 at 06:26 AM.
Jul 5, 2016, 07:33 PM
#3
I was just perusing through some difference between my original "tune" and what the "shop" did and came across the Losed Loop - LT Trim Control table. This looks like it might have something to do with my fuel trim issue? The following values were changed from (left) and to (right)
Low -> Mid : 56.25 to 68.75
Mid -> Low : 43.75 to 62.50
Mid -> High : 1587.50 to 350.00
High -> Mid : 1581.25 to 343.75
Also noticed that the "Flash CEL on Knock" bit in tephra mod options was turned to 0 from 1. This seems kind of odd as this would lead me to believe I will no longer see if/when the car sees knock?
Any input here is greatly appreciated. Thanks!
Low -> Mid : 56.25 to 68.75
Mid -> Low : 43.75 to 62.50
Mid -> High : 1587.50 to 350.00
High -> Mid : 1581.25 to 343.75
Also noticed that the "Flash CEL on Knock" bit in tephra mod options was turned to 0 from 1. This seems kind of odd as this would lead me to believe I will no longer see if/when the car sees knock?
Any input here is greatly appreciated. Thanks!
Jul 6, 2016, 07:04 AM
#4
I reverted the Closed Loop - LT Trim Control table back to what it was originally and still didn't get any fuel trims on my way to work. I'm going to give it an old 93 octane tune I had before any of this happened to see if I get LTFTs back. If not, I would have to assume it's a mechanical issue. At least it will narrow it down.
Jul 6, 2016, 10:30 AM
#5
More updates (if anyone actually reads this)...
I put the car back on the 93 octane tune I used when I just upgraded my injectors on my lunch break. Turned the car on and idled for about 10 minutes before I saw the LTFT Low move. It's rather obvious at this point that the "shop's" tune did something to prevent the car from going into closed loop mode. I'll have to take a closer look at the differences between my tune and the "shop's" tune and see what could be the culprit.
I've ruled out bit 04 in FAA to keep the car in open loop mode. I tested the Closed Loop - LT Trim table changes as mentioned in the above post. I know there are other tables that help dictate when the car goes into closed loop mode. I just don't understand why they did this.
I put the car back on the 93 octane tune I used when I just upgraded my injectors on my lunch break. Turned the car on and idled for about 10 minutes before I saw the LTFT Low move. It's rather obvious at this point that the "shop's" tune did something to prevent the car from going into closed loop mode. I'll have to take a closer look at the differences between my tune and the "shop's" tune and see what could be the culprit.
I've ruled out bit 04 in FAA to keep the car in open loop mode. I tested the Closed Loop - LT Trim table changes as mentioned in the above post. I know there are other tables that help dictate when the car goes into closed loop mode. I just don't understand why they did this.
Jul 11, 2016, 06:54 AM
#6
Two more updates:
1) I was able to confirm that the car was in fact running in closed loop mode during cruise and idle, and open loop when WOT. I can't figure out how to log this with EvoScan, but I can log it with my bluetooth OBD II adapter and the Torque app for my Android phone.
2) Back on the e85 (finally), and fuel trims are still zero. Drove it about 50 miles so far with a few WOT pulls in 2nd, 3rd, AND 4th. Still no movement. But again, it's still running closed loop. So why wouldn't the fuel trims change when in closed loop mode here?
1) I was able to confirm that the car was in fact running in closed loop mode during cruise and idle, and open loop when WOT. I can't figure out how to log this with EvoScan, but I can log it with my bluetooth OBD II adapter and the Torque app for my Android phone.
2) Back on the e85 (finally), and fuel trims are still zero. Drove it about 50 miles so far with a few WOT pulls in 2nd, 3rd, AND 4th. Still no movement. But again, it's still running closed loop. So why wouldn't the fuel trims change when in closed loop mode here?
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