Motiv Flex Fuel Installation Guide

[Erichale77]

1-3% is fine. If it's jumping a lot or to 100%, it is probably around where your 2nd lpfp activates. I'm on my phone so can't easily search, but if you look in the main n54 stock dme flex fuel thread you will see a post detailing how to fix. You must wire your 2nd lpfp as a positive trigger.

What about a third lpfp? I plan on wiring one on ekp second off ignition and third off of hobbs. Will that be ok?

 

[Jake@MHD]

What about a third lpfp? I plan on wiring one on ekp second off ignition and third off of hobbs. Will that be ok?

So two will be constantly running? Should be fine as long as the Hobbs one is a positive trigger to the relay.

 

[Erichale77]

Yes and thanx.

 

[conair]

I have. Mine will fluctuate a percent or two or 3 during a single gear pull) and I had it jump to 100 mid pull in 3rd gear recently for about 150 rpms. I was told any variances like that, or the jump to 100 or 0 could be indicative of a bad ground. I haven't had time to mess with mine yet since it's been fairly consistent. Does yours always happen at 13psi, or does yours "always happen" but at 13psi. Mine was at 22psi when it jumped to 100. Time to check the flexfuel ground. Not sure what could be wrong with it since it's the oem ground point.

It always happens \when the 2nd lpfp is triggered, which is about 13 psi for me.
I rewired my PR fuel pump harness today to have positive trigger on the hobb switch.
Tried changing the ground for the FF box as well.
Didn't change anything, still seeing spikes in the voltage in the same spots.

 

[Jake@MHD]

@blisstik can you post your wiring diagram here that fixed your spikes during lpfp activation?

 

[Jake@MHD]

I'm not positive that is correct. I will try and verify tomorrow.

 

[conair]

For any one wondering, the suggested wiring change did not solve the voltage spikes being seen by the ff box and ethanol content sensor. At this point, the cat is still seeing spikes in the ethanol content and is still unsafe to drive

 

[matreyia]

For any one wondering, the suggested wiring change did not solve the voltage spikes being seen by the ff box and ethanol content sensor. At this point, the cat is still seeing spikes in the ethanol content and is still unsafe to drive

I don't have cats. Downpipe no cats. Does this affect me regardless?

 

[Jake@MHD]

For any one wondering, the suggested wiring change did not solve the voltage spikes being seen by the ff box and ethanol content sensor. At this point, the car is still seeing spikes in the ethanol content and is still unsafe to drive

I will have something for you to try today.

I don't have cats. Downpipe no cats. Does this affect me regardless?

He meant car* lol

 

[matreyia]

W

I will have something for you to try today.



He meant car* lol

Why would it be unsafe to drive with spikes? Not that I plan to drive it unfixed. I am doing some maintenance and will log and send to you and Motiv soon.

VT

 

[Jake@MHD]

W

Why would it be unsafe to drive with spikes? Not that I plan to drive it unfixed. I am doing some maintenance and will log and send to you and Motiv soon.

VT

You can certainly drive it normally. Going WOT / when the 2nd lpfp activates it gives a false spike in the ethanol reading causing a momentary increase in timing.

 

[langsbr]

You can certainly drive it normally. Going WOT / when the 2nd lpfp activates it gives a false spike in the ethanol reading causing a momentary increase in timing.

As a work around, could you unplug the flex fuel module, run a non flex tune, and just have a few codes, but still be safe to drive in any conditions?

 

[Jake@MHD]

As a work around, could you unplug the flex fuel module, run a non flex tune, and just have a few codes, but still be safe to drive in any conditions?

Correct, if the codes even pop. Or if you are custom tuned, you can just set the pump and E tables the same.

 

[tan_rich]

do we still need to be in beta to flash the flex fuel maps or is the ots stg 1/2 maps good to go?

 

[tan_rich]

After installing everything, my car cranks starts up, gets to 1.5k rpms then dies? Any ideas

 

[Jeffman]

This must be throwing a code. What codes do you get?

 

[tan_rich]

This must be throwing a code. What codes do you get?

No code interestingly enough. I undid the wiring, ran it stock and it worked fine. Redid the wiring and it works now.¯\_(ツ)_/¯ Ill roll with it LOL!.

 

[101duck]

Having issues with a hard 2ABC and 3100 code after doing this with the v8 OTS pump93 map. FF sensor reading fine. just those codes. have tried to write a custom file and when i got to flash custom map it wont appear in the list. Any one know why?

 

[Jake@MHD]

Having issues with a hard 2ABC and 3100 code after doing this with the v8 OTS pump93 map. FF sensor reading fine. just those codes. have tried to write a custom file and when i got to flash custom map it wont appear in the list. Any one know why?

This is a more general MHD issue than a FF issue. Did you check the N20 sensor checkbox? What is your altitude? And what folder did you put the custom file in?

 

[101duck]

This is a more general MHD issue than a FF issue. Did you check the N20 sensor checkbox? What is your altitude? And what folder did you put the custom file in?

I worked out the tune issue. Made sure the min voltage was set to .50v eca is reading properly. But nothing is removing the 2abc code.

I will remove the eca and flash back to stock see what happens from there. I am curious. If you have purchased the flex module and flash a ots pump map does it always add the flex logic from that point on?