Motiv Flex Fuel Installation Guide

[Jeffman]

There’s also a mixing time lag to be mindful of. Yesterday I added about 6 gallons of E85 (est 75% ethanol) to my tank that had about 10 gallons E10 gasoline. Initially the ethanol % reported by MHD was >42% and then it settled down to about 34% +/- 0.4% after about 15 minutes while driving. Presumably the denser E85 sinks below the gas in the tank and is picked up first by the LPFP - hence the ethanol spike. Driving mixes everything over time. So probably it would be a best practice not to go WOT within the first ~15 minutes after changing the fuel type to allow proper mixing, proper ethanol % detection, and hence proper FlexFuel tuning interpolation.

 

[rev210]

I think my E content seems consistant ?
Is this sort of variation a worry + or - 1%?
Still looking into to E content discrepancies. This log shows 80% E , however it was E85 fill. Doing some testing now on low E (9%) to see what happens.
I did try 0% E and at one point the FF decided I had 100% E briefly , I replugged the sensor and did a small % fill of E85 which fixed it.
E85 logs
https://datazap.me/u/rev210/e-content?log=0&data=3-24 3rd gear pull.

https://datazap.me/u/rev210/normal-driving-log-e85?log=0&data=3-24 normal driving.

 

[Jeffman]

I think my E content seems consistant ?
Is this sort of variation a worry + or - 1%?
Still looking into to E content discrepancies. This log shows 80% E , however it was E85 fill. Doing some testing now on low E (9%) to see what happens.
I did try 0% E and at one point the FF decided I had 100% E briefly , I replugged the sensor and did a small % fill of E85 which fixed it.
E85 logs
https://datazap.me/u/rev210/e-content?log=0&data=3-24 3rd gear pull.

https://datazap.me/u/rev210/normal-driving-log-e85?log=0&data=3-24 normal driving.

You’re looking good. E % looks very stable.

 

[Dyyd]

In the log he provided above, it only changes by 1-2% during the pull. This could be from flow through the sensing element.

Hello.
It appears 1-3% fluctuation during wot is quite normal. However when using load based tuning this often causes load to be briefly over target and results in throttle closure.

I would like to see that the E content would be filtered or averaged over a short period of time (5 sec - couple minutes) Guess this could be done in the motiv box if it contains enough hardware or in the dme in which case the averaging time could be parametrized for user to choose. This would solve the spiking problem as well.

 

[langsbr]

I wouldn't call what @langsbr is getting now "spikes" haha. It looks to have settled around 19.2% E at the end, and the highest it went was 21.2%. It just looks like more due to the graph scaling.

@jyamona how much variance do I need to accept as normal? I filled up earlier in the week with 93 (which I think may not even have 10% ethanol). I have driven a good 60 - 100 miles before I started looking at the ethanol content, and I see fluctuations from 0 - 10%.

Hide legend Reset zoom

 

[Jeffman]

That doesn’t look anything like what I get. I only see E variations in the first 15-20 minutes or so after blending E98 with 93 octane. It then reads at most +/- 0.4 E%.

 

[langsbr]

I'm going to redo the ground connection again and see if it improves. I already moved it from the ground stud to the shock tower bolt, and I made sure to remove the paint for a good connection. I guess it's possible the crimp on the ring terminal isn't very tight or something, but I would expect it to cut out fully rather than fluctuating readings.

 

[fmorelli]

If you don't have a "tight" connection its possible to have oxidation and resistance issues - this is a low voltage application. Poor grounds are the devil. Failed grounds so much easier to diagnose. I actually have 2 ECA's in my setup, given I also have a Fuel-It ECA with raw output that feeds the Motiv Flex Fuel. I've never thought to compare the two measurements, but will take a look.

Filippo

 

[NoGuru]

I have been having weird readings lately. I looked over and saw my E was at 100% for a 20 minute drive. Guessing I should check my connections.

 

[langsbr]

If you're running the ots maps, it will just reduce boost and timing above e50 to ensure you don't run out of fuel. You can run more than e50 with no issue, its just the point at which you stop seeing gains, and may see less power.

 

[Deleted member 2204]

Thanks! I knew it didnt advance timing any more above E50 but didn't know it actually reduced it (and boost)
Where did you find this info? As this is not something i would want if I know my fueling is ok for any kind of E content.

 

[Jake@MHD]

Thanks! I knew it didnt advance timing any more above E50 but didn't know it actually reduced it (and boost)
Where did you find this info? As this is not something i would want if I know my fueling is ok for any kind of E content.

It needs to reduce boost as it is an OTS map and the user may not have a proper fuel pump. If you wish to take full advantage of your mods and benefit from an E10 - E85 range, then a custom flex fuel tune is something for you to highly consider

 

[matreyia]

I have been having weird readings lately. I looked over and saw my E was at 100% for a 20 minute drive. Guessing I should check my connections.

Your FF module may be on the way out. Mine did the same thing before it went kaputt. I had to contact Motiv for warranty replacement, which they did without any issues. Once the FF module was replaced, my car ran fine again. During the decline of the FF module, I got misfires upon pedal input over 30% then it immediately got worse after the initial misfire and I had to stop and restart multiple times to get home. All connections were fine, no wires were harmed...as I suspected because all connections were painstakingly installed and heat wrapped.

 

[NoGuru]

Your FF module may be on the way out. Mine did the same thing before it went kaputt. I had to contact Motiv for warranty replacement, which they did without any issues. Once the FF module was replaced, my car ran fine again. During the decline of the FF module, I got misfires upon pedal input over 30% then it immediately got worse after the initial misfire and I had to stop and restart multiple times to get home. All connections were fine, no wires were harmed...as I suspected because all connections were painstakingly installed and heat wrapped.

Wow, interesting. I'll see if I can get mine replaced. Seems like the only thing it could be.

 

[matreyia]

Wow, interesting. I'll see if I can get mine replaced. Seems like the only thing it could be.

To be sure, you check the ethanol percentage and it says 100% while active. Then disconnect the ethanol sensor and check again... if it still says 100%, then it is the FF Module. This test procedure was suggested by Jayamona and it is fool proof.

 

[NoGuru]

To be sure, you check the ethanol percentage and it says 100% while active. Then disconnect the ethanol sensor and check again... if it still says 100%, then it is the FF Module. This test procedure was suggested by Jayamona and it is fool proof.

Do you mean disconnect the electrical connection?

 

[matreyia]

Do you mean disconnect the electrical connection?

This is only one way to connect and disconnect the ethanol sensor. I know of no other connection.

 

[Jake@MHD]

Do you mean disconnect the electrical connection?

The plug on the conti sensor. E% does not matter much when debugging, you really need the ECA voltage param as there are various error voltages it can output. What was voltage when yours read 100%?

 

[NoGuru]

The plug on the conti sensor. E% does not matter much when debugging, you really need the ECA voltage param as there are various error voltages it can output. What was voltage when yours read 100%?

Next time it pegs to 100% I will do a manual datalog.

 

[matreyia]

The plug on the conti sensor. E% does not matter much when debugging, you really need the ECA voltage param as there are various error voltages it can output. What was voltage when yours read 100%?

Sorry, I meant to say voltage.