I'm trying to tune my stock '14 Wrangler to operate Flex Fuel on gasoline and E85, and hoping someone might be able to help. So far the cal is still stock.
After 1-2 months of driving only on E85 (80% ethanol), my "Alcohol Percent" bit in the VCM scanner is still sitting at "0%" and the "Fuel Type (SAE)" bit still reads "Gas". The LTFTs are at 30-33% across the map and I'm getting "System Too Lean" error codes (P0171 and P0174). Perhaps I need to do something like the Hellcat FFV patch? But not sure if this applicable for a Wrangler PCM.
Let me give a little more detail.
1. '14 Grand Cherokees with the same 3.6L Pentastar as my JK were flex fuel from the factory, but not the Wranglers.
https://www.edmunds.com/jeep/grand-cherokee/2014/
https://www.edmunds.com/jeep/wrangler/2014/
2. However, the hpt cal file off my JK shows tables and multipliers to adjust for flex fuel operation based on alcohol % (fueling, spark, etc.). But I'm not sure how the PCM determines "Alcohol %" to be able to input it into these tables/multipliers...
3. I've compared my Wrangler hpt file to a FFV Grand Cherokee stock hpt file from the HPT repository and found small differences, but none relating to alcohol % tables or FFV multipliers (fueling, spark, etc.). So it seems the groundwork has already been laid for me to operate my JK flex fuel like the Grand Cherokees.
4. However, as mentioned, after 1-2 months of driving on 80% ethanol, the bits in the VCM scanner for Alcohol % still read "0%" and Fuel Type (SAE) still reads "Gas". So it appears my PCM is not enabling those alcohol tables or multipliers. As a result, I'm getting lean error codes.
5. Neither the FFV Grand Cherokees nor the Wranglers have wideband O2 sensors or an in-line fuel alcohol sensor. So I assume the Chrysler FFVs sense alcohol % based on the LTFT or some other calculation based method? My LTFTs across the operating map have risen to 30-33%, but my PCM still doesn't recognize the increased alcohol content.
6. It seems the only times it runs lean are when the PCM goes into Open Loop. During Closed Loop, seems I'm dittering around stoich just fine.
Questions:
1. Why doesn't my JK recognize the alcohol level if it appears the cal file has all the alcohol tables and multipliers for FFV operation? Is there a hidden bit that I need to turn on? Can HP Tuners add it to the VCM Editor? I've checked all through the hpt file, but haven't found anything to activate an "alcohol %" variable.
2. What's actually causing the lean error codes? Am I past a threshold LTFT? Is it from the O2 sensors zeroing out in OL operation? Or from the calculated AFR (from air charge and fuel mass)? Once/if I can get the Alc % and Fuel Type working, will it stop throwing Lean Error Codes and not lean out in Open Loop?
3. Do I need a Wrangler or 3.6L pentastar specific flex fuel patch? Could I use the Hellcat patch? I'm not sure how to get it and I didn't see it when I opened "OS" in the VCM Editor, as I read in one of the Hellcat FFV patch threads. (But perhaps I needed to be connected to my PCM on the vehicle?) FYI, I'm running the latest versions of VCM Editor and Scanner.
Thank you all for helping me better understand what is going on/what I need to do!