Motiv Flex Fuel Installation Guide

[langsbr]

Has anyone filled up with 93 recently and 0% readings? I know Trumpy provided a bunch of refiners with ethanol exemptions, but wasn't sure if 93 wasn't using it either. My last fill up of 93 has my tank reading at 0%, well until it decides it wants to read up to 5 or 6%. I still can't get a straight answer on what the 'limit' is for acceptable variance. I only put 200 miles on the car yesterday from a full tank and it would go from 0 to 6% at different throttle inputs. It would mostly fall to 0 when WOT, then go up when cruising.

 

[Jake@MHD]

Has anyone filled up with 93 recently and 0% readings? I know Trumpy provided a bunch of refiners with ethanol exemptions, but wasn't sure if 93 wasn't using it either. My last fill up of 93 has my tank reading at 0%, well until it decides it wants to read up to 5 or 6%. I still can't get a straight answer on what the 'limit' is for acceptable variance. I only put 200 miles on the car yesterday from a full tank and it would go from 0 to 6% at different throttle inputs. It would mostly fall to 0 when WOT, then go up when cruising.

Yes that is not normal. 1-2% can be expected but dropping to 0 sounds like either: a loose connection somewhere, ground interference, etc.

If you want to try and help diagnose some, unplug the connector on the continental sensor and monitor ECA voltage as you drive around, but DO NOT go WOT, as your E reading will be obviously incorrect. Report back!

 

[Jeffman]

This is all good to know. So far, so good for my Motiv FlexFuel install and ethanol percentage monitoring.

 

[NoGuru]

Here is a log I got during some E fluctuation https://datazap.me/u/noguru/checking-e-fluctuation?log=0&data=13-14-24

 

[Jeffman]

It’s definitely reading your voltage as varying quite wildly. That could be due to the sensor being messed up somehow, or the wiring not being 100% to the ECU or ground.

Potential issues with the sensor could arise from:
Heat
Vibration
Water
Damage
Loose wiring
Remind us where did you mount your ethanol sensor?

My ethanol Sensor is under the footwell - I didn’t want it near the engine block fearing temperature variations could affect it.

 

[NoGuru]

It’s definitely reading your voltage as varying quite wildly. That could be due to the sensor being messed up somehow, or the wiring not being 100% to the ECU or ground.

Potential issues with the sensor could arise from:
Heat
Vibration
Water
Damage
Loose wiring
Remind us where did you mount your ethanol sensor?

My ethanol Sensor is under the footwell - I didn’t want it near the engine block fearing temperature variations could affect it.

Thanks Jeff, I think I mounted it under the foot-well but will need to double check.

So the last mod I did was inlet relocation but I don't think that would affect anything here but just something to note.
I am going to retrace the wires this week and try and make sure the connection is still good. I have new turbos going in next week and don't need this interfering with my tune.

 

[Jeffman]

I am going to retrace the wires this week and try and make sure the connection is still good.

Good luck! If despite retracing the wires and checking everything you’re still getting these voltage fluctuations you’re best bet may be to disconnect and reconnect the wires.

 

[Nosrok]

Flex fuel jumping to 100% during WOT pulls. Voltage logs show a step from 1.6 to 2.19 then pegs at 4.98 in the span of 200 rpm between about 3600 and 3800, I haven't disconnected my 2nd hpfp pump but that is around when it kicks in.

The issue started happening after the car sat for a month. Before that it was never an issue, have been running the kit since launch. So a little over a year.

Car: 2008 135i
Vargas GCs
Double shotgun
Bucketless 450
FBO

I've read through the posts looking for ideas to troubleshoot my own setup:

So far I've swapped relays from another 08 135i.
Checked wiring and grounds
Drove through a tank and a half of gas to rule out bad gas.


Any suggestions or ideas would be greatly appreciated.

Hide legend Reset zoom

 

[NoGuru]

I think I resolved my erratic fluctuations. The wire harness was resting on my trans. The only test for one drive before I dropped the car at a shop to get new turbos installed but I think that was the issue.

 

[Jake@MHD]

@Nosrok is it only during WOT pulls? So normal driving no issue? If so, it definitely sounds like something kicking on and sending a voltage spike through the chassis grounds.

 

[Nosrok]

@Nosrok is it only during WOT pulls? So normal driving no issue? If so, it definitely sounds like something kicking on and sending a voltage spike through the chassis grounds.

Yup only during WOT pulls but only recently. Before it sat for a month there were no issues. I'm gonna move wires around to see if I have a similar issue as @NoGuru. I do have the harness pushed/tucked between the engine and firewall.
I'll got out for a pull and see what it does. If it persists I'll disconnect the 2nd hpfp and see what happens then.

 

[Rob09msport]

Just curious what did pin 16 originally read.?

 

[Chris@VargasTurboTech]

Anyone care to lend a helping hand. Installed FF for a customer. All wiring double-checked. Ethanol sensor voltage is reading as it should in the monitor, and changes as it should with added ethanol. Getting 0% Ethanol content in the monitor, and correspondingly 0% interpolation. Its a pretty straight forward install, this is our second one, last one no issues. Thoughts, ideas all welcome.

 

[langsbr]

flex fuel map loaded yet? Is it an OTS or a custom tune?

 

[Chris@VargasTurboTech]

flex fuel map loaded yet? Is it an OTS or a custom tune?

Custom tune, it's loaded up. Its possible something is wrong in the map. If anyone is familiar with these maps, we can send the BIN

 

[Jake@MHD]

Map was not formatted correctly (must use the exe tool).

 

[Chris@VargasTurboTech]

Map was not formatted correctly (must use the exe tool).

Tool was 100% used. We will run it through again.

Edit: Fixed even though we ran it through, afterward we changed the bin name to something easy for the customer to find in his folder, FF were no longer the last letters. It's all working now after we ran it through again. Thank you for the help

 

[langsbr]

Jake can tell you which table can't be modified, I think it's one of the afr ones. If that table gets modified on a non Flex fuel map and then run thru the tool it can cause it.

 

[Jake@MHD]

Tool was 100% used. We will run it through again.

Edit: Fixed even though we ran it through, afterward we changed the bin name to something easy for the customer to find in his folder, FF were no longer the last letters. It's all working now after we ran it through again. Thank you for the help

Bin filename has nothing to do with it. MHD auto detects certain hex changes in order to add the FF logic. And if the voltage is reading properly but not the E% it means the logic was not added.

Glad you figured it out regardless.

 

[Chris@VargasTurboTech]

Bin filename has nothing to do with it. MHD auto detects certain hex changes in order to add the FF logic. And if the voltage is reading properly but not the E% it means the logic was not added.

Glad you figured it out regardless.

Great, must have done something when we made changes. We ran it through, then made the bin changes. then flashed it. Once we ran it through after the changes. It worked fine. Thanks again