N54 SOLVED: MOTIV / MHD FlexFuel Readiness Issues?

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Jeffman

Captain
Jan 7, 2017
1,340
I seem to be having more trouble getting OBDII readiness now that I have MOTIV / MHD FlexFuel installed (N54 stock catted DPs ) .
Both
Catalyst: INCOMPLETE
Evaporative System: INCOMPLETE
Last year very similar tunes and presumably same toggles and passed.
Anyone else having similar issues?
CEF4522C-F636-4E51-B50C-893868F7A740.jpeg
 
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matreyia

Captain
Apr 19, 2017
1,373
I gave up and installed stock dp to get inspection passed. Evap NEVER readied...months drive did nothing.
 
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Jeffman

Captain
Jan 7, 2017
1,340
I have stock dp / cats. Hmmm...
@jyamona Jake, any reason why FlexFuel could be causing any Catalyst or Evaporation System readiness issues?
 

matreyia

Captain
Apr 19, 2017
1,373
I have stock dp / cats. Hmmm...
@jyamona Jake, any reason why FlexFuel could be causing any Catalyst or Evaporation System readiness issues?
If you're driving with stock converters, you should initiate the drive cycle and it should become ready in about 10 to 20 minutes if you drive the cycle correctly. Mine literally turned on like within 5 minutes after installing the stock down pipes.

I'm going to assume you know how to do this and that the drive cycle must be initiated when the engine is stone cold.
 
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Jeffman

Captain
Jan 7, 2017
1,340
I just realized I had my exhaust flap connector disconnected. Just reconnected this morning. Hopefully this will help set readiness on the Catalyst and/or Evaporative System.
 

bantam

Corporal
Nov 20, 2017
102
My guess would be that the cat readiness is incomplete because of your tune. Worth double checking your flash options. Unsure about EVAP readiness, doubt the exhaust flap will fix anything
 
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matreyia

Captain
Apr 19, 2017
1,373
I just realized I had my exhaust flap connector disconnected. Just reconnected this morning. Hopefully this will help set readiness on the Catalyst and/or Evaporative System.
Forgot to mention, i also flashed back to stock after stock cats installed. Otherwise might give faults on readings...running to rich..etc. disconnected port injection aic controller and flashed stock tune.

FF module should not affect stock flash and needn't be touched.
 

bantam

Corporal
Nov 20, 2017
102
Evap will not hit ready with FF wired in, as the DMTL wire is used for ethanol signal. You will need to put that stock wire back and flash a non-FF map temporarily.
Jake, my flex fuel is installed, but the orange and green wires are disconnected for the time being until I sort out my straight E85 tune.

Can I measure the voltage across those two wires to determine my actual ethanol content in the system? If so, what is the corrElation?
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
Jake, my flex fuel is installed, but the orange and green wires are disconnected for the time being until I sort out my straight E85 tune.

Can I measure the voltage across those two wires to determine my actual ethanol content in the system? If so, what is the corrElation?
IIRC, orange powers the ECA and must be hooked into the DME as it provides the steady 5v required (separate from conti E sensor power, which is 12v). Green is the E% output, which you could voltmeter and read. Conversion data points can be found in the XDF.
 

bantam

Corporal
Nov 20, 2017
102
Thanks,and I think this applies as well for people trying to ready their car for emissions as well:

So the orange wire can stay in the DME with or without the flex fuel logic enabled in MHD?

In the FF module install instructions, it says to leave both the orange and green unhooked unless the Mhd logic has been flashed.
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
Thanks,and I think this applies as well for people trying to ready their car for emissions as well:

So the orange wire can stay in the DME with or without the flex fuel logic enabled in MHD?

In the FF module install instructions, it says to leave both the orange and green unhooked unless the Mhd logic has been flashed.
I would unplug them both when not running an FF map. I just stated to plug the orange in temporarily if you wanted to volt meter the green and check your content quick.
 
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bantam

Corporal
Nov 20, 2017
102
I would unplug them both when not running an FF map. I just stated to plug the orange in temporarily if you wanted to volt meter the green and check your content quick.
I filled up with 16 gallons of unknown quality E85 (ran the car to almost completely empty) and then put about 20 miles worth of driving on it before taking this reading... Do the values in the XDF seem reasonable to you? Per the sensor, I am at ~68% ethanol, so I likely was getting something in the low E70s from the pump

27188
 

Jeffman

Captain
Jan 7, 2017
1,340
Evap will not hit ready with FF wired in, as the DMTL wire is used for ethanol signal. You will need to put that stock wire back and flash a non-FF map temporarily.
@jyamona Will the FlexFuel wiring also prevent readiness on Catalyst?
(I can pass emissions in PA with one not ready.)
 
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jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
I filled up with 16 gallons of unknown quality E85 (ran the car to almost completely empty) and then put about 20 miles worth of driving on it before taking this reading... Do the values in the XDF seem reasonable to you? Per the sensor, I am at ~68% ethanol, so I likely was getting something in the low E70s from the pump
XDF is correct and your math is correct as well. That E content seems reasonable. It will be a bit higher next fill-up too, since the tank it never really empty.

@jyamona Will the FlexFuel wiring also prevent readiness on Catalyst?
(I can pass emissions in PA with one not ready.)
If you have stock DP / cats and do the drive cycle, they should hit readiness like normal. The only reason they wouldn't is if you lean out cruising AFR on ethanol above 14.7, then sometimes it won't. You must keep idle / cruise afr at stoich in order for them to set (in addition to have the cats).
 
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Jeffman

Captain
Jan 7, 2017
1,340
XDF is correct and your math is correct as well. That E content seems reasonable. It will be a bit higher next fill-up too, since the tank it never really empty.



If you have stock DP / cats and do the drive cycle, they should hit readiness like normal. The only reason they wouldn't is if you lean out cruising AFR on ethanol above 14.7, then sometimes it won't. You must keep idle / cruise afr at stoich in order for them to set (in addition to have the cats).
I haven’t messed with my 93 Octane map in over two years. My Fuel (main) table AFR is set to 15.999 ( leaner than 14.7 stoichiometric) at 1800-2200rpm and below 60 load for my FlexFuel map. See table below. Could this prevent Catalyst readiness? Should make that whole area in the cruising range 14.671 like all of the other values nearby in the table? I have stock cats and am having a heck of a time getting Catalyst readiness.
Thanks
A47405EC-8C50-495C-801F-2D9F50868D65.jpeg
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
I haven’t messed with my 93 Octane map in over two years. My Fuel (main) table AFR is set to 15.999 ( leaner than 14.7 stoichiometric) at 1800-2200rpm and below 60 load for my FlexFuel map. See table below. Could this prevent Catalyst readiness? Should make that whole area in the cruising range 14.671 like all of the other values nearby in the table? I have stock cats and am having a heck of a time getting Catalyst readiness.
Thanks
Yes, do not use vals over 14.67 - 14.7. This can prevent readiness because it is looking for the proper voltage from the rear o2's at the same time, and they are closely calibrated around stoich, so running 15.x will always keep them out of range when it's doing the check (right around where you changed them).
 
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Jeffman

Captain
Jan 7, 2017
1,340
Yes, do not use vals over 14.67 - 14.7. This can prevent readiness because it is looking for the proper voltage from the rear o2's at the same time, and they are closely calibrated around stoich, so running 15.x will always keep them out of range when it's doing the check (right around where you changed them).
Awesome feedback. This explains why I could never get Catalyst readiness for the last ~3 years LOL!
 

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