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DFI and ECMDiscuss all aspects of DFI (Digital Fuel Injection), ECMs (Electronic Control Module), scanners, and diagnostic equipment. Fine tune your Third Gen computer system for top performance.
Was supposed to make the switch to E85 awhile ago, but with changing engines and only a few stations here in new Jersey offering it at the time, not to mention other things happening in life, I just put it on hold. Now with more stations offering corn oil, I figured I would just get it done today. This is for you EBL guys looking to make the switch and haven't yet, or are considering it, and are not sure what to do...
O2 sensors are probes that measure air in your exhaust using the Lambda signal. They don't necessarily measure a specific air/fuel ratio per se, they just measure oxygen. A typical Lambda reading will read the same using any fuel. The confusion normally comes into the equation when an air/fuel ratio is calibrated into the ECM's firmware, or even when calibrated into your O2 gauge using just one fuel type. But in the EBL's case, you can calibrate whatever air/fuel ratio you want to in the system, and with gauges today, you can switch to just about any fuel type if need be. So in this case, we will be making the stoich value of 14.7 AFR now becoming 9.80 AFR in the system, with the INT/BLM of 128/128 now summing up that very ratio, 9.80 AFR as its' new target...
You can start from scratch running E85, or with an already tuned engine, it does not matter. In this case though, my new engine is already tuned, so I'll just be focusing on the switch itself. Total parameters we will need to adjust immediately when converting over to E85; there are eight of them, and they are as follows;
* Closed Loop - Stoich AFR
* Open Loop - Max Lean AFR
* Open Loop - Idle Lean Limit
* Open Loop - AFR vs RPM & VAC
* Choke- AFR
* Crank - AFR
* PE - AFR Commanded
* HWY - AFR vs MAP
So open up that XDF, and pull up those areas. It's as easy as changing the values over to average the new air/fuel ratio, which is all we're really doing, but I will go over with you regardless. However be aware that E85 burns very differently than Gasoline, so don't just go by the air/fuel ratio percentage differences themselves and think you're done, I highly recommend tuning the engine even further after the conversion is complete, preferably in Lambda, or a gauge that has been calibrated for E85 so you don't confuse yourselves. Lets go over them one by one, and why. Just note, this is just to help everyone get themselves started;
Closed Loop - Stoich AFR;
Simply change the initial 14.7 AFR ratio to reflect 9.75 AFR.
Simple recalibration, 9.75 is the new stoich...
Open Loop - Max Lean AFR
Preference based on the tuner. I set mine differently in conjunction with other areas, so I don't need the engine running any Leaner than the target, just slightly Leaner. So it is up to you. You can change it to offset the new stoich value based on the existing bin values, so in this case just switch the 16.5 AFR to roughly an 11.5 AFR, or slightly richer. It's up to you, just dial in as needed.
Open Loop - Idle Lean Limit
Another preference based on the tuner... some may want this limit to be Leaner. Solely up to you, however if you are unsure, just change the 13.5 AFR to 8.5 AFR, and again, dial in as needed...
Open Loop - AFR vs RPM & VAC
Another preference based on the tuner... some make drastic changes in this area, some just ignore it. In either case, if you are unsure what to do, remember that we are essentially incorporating and averaging the new air/fuel ratio into the equation. So one look at this table, and you will see that it is basically five points away from where it needs to be. So if you are unsure, just highlight the whole table, then select and minus out 5.00 value points. When it comes to E85, wide open throttle AFR is about 7.8 AFR, so you will want to see those 12.80's in the 0 Hg column now reflecting 7.8. Again, this is just to get you started, dial in as needed....
Choke- AFR& Crank - AFR
I went back and forth with these areas, and I found that they needed very little attention. You can alter them slightly to see if they make any real difference, but I haven't seen any to write home about. But again for the sake of this thread, just minus out forty to fifty percent in both tables, and dial in if needed....
PE - AFR Commanded
I mentioned a little earlier that wide open throttle AFR for E85 is about a 7.8 AFR. So just change the existing 12.8 AFR that is in there already to reflect 7.8 AFR. Done...
HWY - AFR vs MAP
This area is again based on preference. I do not run Highway Mode, so my values do not matter. However, based on the new stoich value of 9.7 AFR, you will want to highlight all of the values, and again minus out 5.00 value points from them. Dial in if needed.
That's about it for this little E85 conversion. I'm adding a few pics of the change today, and will be adding videos of the engine running as I dial in the new fuel. Will also be installing a flex fuel sensor shortly, so switching from bank to bank with every gas station will be an absolute breeze (ethanol percentages vary, so having a few bins ranging from 14.7, 13.7, 12.7, 11.7 10.7 and 9.7 AFR ready and waiting is extremely useful), and the flex fuel sensor will tell me in a matter of seconds right after the tank has been filled which bin to use. But that part is optional, as most E85 fuel sources don't deviate too far away from its' stoich value. Another plus is that I can also switch back to pump gas in a matter of seconds, if ever in a missing E85 fuel station jam...
First impression, I like it so much better than pump gas. Was craving french fries after all of that corn oil tuning, and you better believe I picked some up not too long ago lol. First E85 run was over by Newark Airport here in New Jersey, only nabbed a few bucks worth with the can, a little less than a quarter of a tank it gave me. Engine was up and running immediately after the change though, regardless. IAC steps need a little attention, but that's about it. Adding pics of the WUD indicating the old pump gas AFR target with the new E85 AFR target in relation with where the INT/BLM's are, which are both back on point...
- Rob
Last edited by Street Lethal; Mar 25, 2021 at 04:41 PM.
I told the girl in the drive thru no damn pickles, and after the first giant bite I soon realized she must have thought I said extra pickles, I was almost in tears gagging lol...
Second day of my little E85 adventure. Rather than have those following along sitting through a boring datalog from cold to hot, I uploaded three videos ranging from cold start Open Loop, warm engine Closed Loop, and hot engine Closed Loop. Blipping the throttle a few times, nothing crazy. However, the VE is done, she wants to go. So the next videos I'll have for you guys will be out on the city streets messing around with more testing. Wanna test the limitations of spark advance with this new fuel. Just note that the IAC steps are higher at idle because of the much richer AFR (obviously), and I am seeing between 100 steps and 77steps from 150*F through 210*F. My operating temp is around 190*F or so. I am still running the stock 48mm throttle body, and I am still running Tuned Port Injection, just on a much larger displaced engine. So in relation with the IAC steps keep that in mind as you will need to tailor the minimum step settings to your engine, otherwise the system will pull the steps too low, tugging on your commanded RPM, and you'll soon find yourself doing the stall saver surge dance. So be mindful of that...
I find it easier to just work with gas scale since thats what most ppl understand. 14.7 stoich for idle and cruise, 12.5 to 13.0 is target afr for wot na. Simple and easy, no reason to use e85 scale imo. Also nice if you run a wideband, most gauges are in gas scale from 10 to 20 afr range
I do understand what you're saying, but the gas scale is just a hard coded calibration that many people had gotten used to back in the day. In this case though, switching from bank to bank allows the fuel scales to change automatically with the bank being selected, so one can go back and forth with the scales on command, and keep the readings as accurate as possible with the fuel being used. If I were driving w/E85 with the EBL data logging, and I noticed the WUD screen's cAFR stating 14.7 it would drive me insane, kinda like a steering wheel that is not centered properly, but that's just me. I tune using Lambda though, which is why my wideband data is not being displayed on the screen, so it's all the same readings to me in the end either way...
Was pushing the timing to see when it would give in, but no knock whatsoever. Was upping the timing as high as 40* at wide open throttle, but no increase in performance to do any cartwheels over, so back down it went to where I originally had it. Though it was nice to see this fuel in action, definitely took a beating, despite me cringing while holding the pedal to the floor. Substantially brought the IAC steps down with additional tuning, went from 77 steps at 190* F at idle to about 45 steps at the same temperature at idle. Also decreased the below area as well about twenty to thirty percent during colder starting conditions. Engine is running exceptionally well in all areas, hoping to get this thing to the track very soon...
Liberal New Jersey didn't make it easy during the early stages of the pandemic, they were pulling people over who weren't supposed to be out driving, and when pulled over we had to prove we were working in a manner that was beneficial to the public (hospitals, banks, etc). Ironic thing here though, is that I was one of the approvers of the track's PPP loan, so rather than waste hundreds and hundreds of dollars racing during the season and never getting a spot, I was writing them a check instead. But yeah, the early part of the season was a waste, and by the time the state started to open things up, a lot of us were too annoyed to enjoy anything. We did go out to your neck of the woods (state wise) over by Parx Casino, but they have no room accommodation, so sad to say most of this season for us was Atlantic City, and tuning engines for members running the EBL system...
