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Discussion Starter #1
This is a hypothetical question due to the fact I just loaded my base tune and the car is running pig rich at wot (8:1) but pat sent me a tune for e85 but I told him I didn't have the flex fuel sensor or pump installed yet.

So my car has a code that the flex sensor cant be found of course because it's not installed.

So my question is, is the car going pig rich because it's not installed and perhaps the car will default to the highest % e85 table to protect against a lean condition if the sensor would ever fail?

I sent my tune to pat but I'm tempted to install the sensor and take it out again.
 
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Generally there is a default setting which I usually set to E45 to split the difference as well as setting you can turn on to set a CEL in the event of failure.
ok so it is possible that pat might have a different values that it defaults too, I suppose running that rich isnt ideal on break in but it was only about 10 minutes before I brought it back in and sent the log off.
 

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ok so it is possible that pat might have a different values that it defaults too, I suppose running that rich isnt ideal on break in but it was only about 10 minutes before I brought it back in and sent the log off.
Do you have reason to believe the sensor is not working? Are you seeing a value for alcohol %?
 

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ok so it is possible that pat might have a different values that it defaults too, I suppose running that rich isnt ideal on break in but it was only about 10 minutes before I brought it back in and sent the log off.
Pat uses 90hz as the fail frequency. 50hz is 0% and 150hz is 100% so 90hz is 40% ( 90hz-50=40%). As for it being pig rich it will be because the PCM thinks the car has E40 (you have pump in it right now correct?) and the a AFR of 12.4 stoich. The rest is probably just the fact that it is a base tune and the MAF table is off.

The biggest risk with a FF sensor fail is on WOT because if you have E75 in the tank and the PCM thinks its E40 you will be running lean. On the flip side if you have pump gas and the PCM thinks it's E40 then you will have too much timing under WOT. Of course if you have a MIL light you shouldn't be doing WOT pulls.
 

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Discussion Starter #6
Do you have reason to believe the sensor is not working? Are you seeing a value for alcohol %?
Yes I didn't have it installed. I told him the pump wasn't installed because my tank was full to the tits and I didn't have anywhere to drain it before I tapped it. He said it was ok but I didn't explain the sensor wasn't installed as I was going to do it together.

So I have the sensor installed now but I dont understand what connector is for the ECU as I see 3 with the red tab.
 

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Yes I didn't have it installed. I told him the pump wasn't installed because my tank was full to the tits and I didn't have anywhere to drain it before I tapped it. He said it was ok but I didn't explain the sensor wasn't installed as I was going to do it together.

So I have the sensor installed now but I dont understand what connector is for the ECU as I see 3 with the red tab.
It's the one closest to the head. Make sure you get the right pin also.
 

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Discussion Starter #8
Mm I found it dudes!
 

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Yeah, I should have realized there was an issue with the ecm throwing a code saying the flex sensor wasnt found but I didnt think it would default to a more rich fuel map.

My cmd AFR was 13.1 on pump fuel and wot was dropping to 8.5 AFR.

I never knew about a safe mode should that sensor fail until I started to think what could throw my AFR off so much.

I installed the sensor and the CMD afr is back to 14.8, no more spuddering or stalling at idle, car ran way way better on the first tune. My error, as always, im learning ;)
 

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Yeah, I should have realized there was an issue with the ecm throwing a code saying the flex sensor wasnt found but I didnt think it would default to a more rich fuel map.

My cmd AFR was 13.1 on pump fuel and wot was dropping to 8.5 AFR.

I never knew about a safe mode should that sensor fail until I started to think what could throw my AFR off so much.

I installed the sensor and the CMD afr is back to 14.8, no more spuddering or stalling at idle, car ran way way better on the first tune. My error, as always, im learning ;)
Just some in info for you now that you are going E. The fuel map (MAF/VVE maps) is not what changes with E% it's the stoich value that changes. Also start logging your WB in lambda it's a lot easier then AFR.

When you change E% the stoich will change as well as your PE AFR, but when you use lambda you will always have a commanded 1.0 under normal operation and say .78 under WOT regardless of E content.
 
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Just some in info for you now that you are going E. The fuel map (MAF/VVE maps) is not what changes with E% it's the stoich value that changes. Also start logging your WB in lambda it's a lot easier the AFR.

When you change E% the stoich will change as well as your PE AFR, but when you use lambda you will always have a commanded 1.0 under normal operation and say .78 under WOT regardless of E content.
Thanks, ill try to sort that out as I know a lot of people prefer that method and Ive read about lambda a lot just never thought id get E up north so didnt really worry about changing my wideband to read that way.
 
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