Weird MAF voltage with FIC 6. - Miata Turbo Forum - Boost cars, acquire cats.

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Old 11-05-2016, 11:38 PM   #1
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Default Weird MAF voltage with FIC 6.

Hello everyone. I recently joined this forum, a lot of the knowledge i know about turbos came from this forum. My miata is an 03 1.8 VVT. Recently i decided to turbo my car for a low 4 psi to begin with. I had a AEM FIC 6 laying around from a build one of my friends did a while back. I reset the FIC and installed the latest calibration and i started to wire it. I am running the stock injectors and fuel pump; all maintenance has been done on vehicle. When the vehicle starts, all tables 0 out, the car runs extremely rich and dies. When i disconnect the FIC unit and use the jumper harness, the vehicle runs perfectly fine. I did notice the FIC sees 6 volts coming from the MAF at key on and it just stays at 6 volts when the car is running. When i connect the jumper harness i get 1.4 volts with key on and about 1.8 volts running at idle (increases to about 3.6 volts at about 5k rpms) at the MAF signal wire. I verified through a continuity check the wire is the correct MAF signal wire and that is not shorted to power, ground, or other wire in the harness. From the research i have done, a lot of members state our ECUs don't really care about seen boost and that is not worth messing with the MAF signal up to like 12 psi. I am writing this to see if someone has had this issue before. I am splicing directly into the harness since a lot of websites want a DMV signed form that states the extension harness (boomslang harness? aem extension harness PNP?) will only go to a race only vehicle. I did not want to deal with that so i installed it straight into my harness. I used a 1K ohm resistor on the o2. This has been done with the stock exhaust system without adding any boost. Question is, will the ECU set a DTC for mass airflow seen boost? and can i completely avoid clamping the MAF altogether. Thanks for the help.

Last edited by Santia1; 11-05-2016 at 11:49 PM.
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Old 11-06-2016, 09:08 AM   #2
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Miata MAF are not 0-5V devices last I checked. If your band-aids are expecting a 0-5V maf signal, you're gonna have to do some input filtering.

Megasquirt Support Forum (MSEXTRA) ? Some Mazda MAFs are NOT 0-5 volt devices (View topic)

Or quit sucking and buy a megasquirt.
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Old 01-10-2018, 08:45 PM   #3
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Quote:
Originally Posted by deezums View Post
Miata MAF are not 0-5V devices last I checked. If your band-aids are expecting a 0-5V maf signal, you're gonna have to do some input filtering.

Megasquirt Support Forum (MSEXTRA) ? Some Mazda MAFs are NOT 0-5 volt devices (View topic)

Or quit sucking and buy a megasquirt.
Useless post....

OP, You have read correctly, in our cars we can get away with bypassing the MAF entirely and not set of the CEL making 230 whp on the NB2. This has been done many times. I personally have the AEM FIC and sent in my Boomslang harness back to Rustin to bypass the MAF entirely. There is a resistor that you may need to use for the MAF signal as well. It seems this resistance is slightly different across the NB2 cars, confirmed by AEM and Boomslang that it may cause issues. I would try to bypass the MAF and see if you are running like stock with the values in the maps all zeroed out.

For those that don't get it, some people use the AEM FIC and other piggy backs because there is no alternative in states that require OBD2 inspection checks. This is the one and only reason I am using the FIC, which is much more for your money in terms of control than the Voodoo box (both ultimately do the same thing) . And please don't tell me it's easy to swap injectors and remove the MS to get the inspection done.....who has that time, I got kids to feed =)
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Old 01-10-2018, 09:02 PM   #4
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Which post was useless?
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Old 01-28-2018, 05:38 PM   #5
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"Or quit sucking and buy a megasquirt."

Like I said people don't use the piggyback solution because its better/cheaper etc...it's because usually they don't have a choice....
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Old 01-28-2018, 05:46 PM   #6
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If you say so. But, there was useful information in that post. Just because it contradicts your experiences doesn't mean that it's not.
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