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-   -   94-95 & 96-97 MAF Delete Discussion (https://www.miataturbo.net/megasquirt-18/94-95-96-97-maf-delete-discussion-14166/)

Arkmage 01-02-2008 03:38 PM

me too, but no code scanner :( If anyone has one they are willing to loan me for a few weeks it would help the cause significantly.

I put a 2.2K-ohm resistor between pin 3 & GND to simulate the AIT.

I also put the 1.5M-Ohm resistor between pin 4 & 5. This should have output approximately 1.4 Volts to the ecu.

*edit* Scott, you know anything about the programmable outputs on the MS? Is there a 0-5V programmable output? I know there are 12V switched, but I think our odds of success are higher with a variable output since the ECU was complaining about lack of "circuit activity" rather that "broken circuit". I think it actually wants to see the airflow vary :(

Braineack 01-02-2008 03:40 PM

any chance you can route you AIT through the MAF harness to try to rule it out? that should be sufficient it is for the 90-93 at least. then you can fiddle with just the MAF signal.

Arkmage 01-02-2008 03:44 PM


Originally Posted by Braineack (Post 192437)
any chance you can route you AIT through the MAF harness to try to rule it out? that should be sufficient it is for the 90-93 at least. then you can fiddle with just the MAF signal.

I could, but it would take a bit more time and effort. I ran independent wires for the AIT on the cold side. They are tucked into the other harnesses and are not very easy to access. I'd prefer not to re-wire stuff that is already functioning properly on the MS. I might buy another one to toss in there as an alternative for testing.

Braineack 01-02-2008 03:46 PM

can you at least tap the signal there into your harness? the ecu needs to share the ait signal. i know that.

Arkmage 01-02-2008 03:56 PM

Sigh... then I have to change my bias resistance, redo easytherm, reflash again, etc etc. I'll see what I can do this weekend, but I may just buy a second sensor to tap in there.

Saml01 01-02-2008 04:11 PM


Originally Posted by Arkmage (Post 192445)
Sigh... then I have to change my bias resistance, redo easytherm, reflash again, etc etc. I'll see what I can do this weekend, but I may just buy a second sensor to tap in there.

If you want I will send you a sensor for testing. Its not a screw in, but its a rubber bung type and open element otherwise identical in every way to the screw in type.

You can send it back to me when you are done.

PM me your address, ill send it tomorrow.

Arkmage 01-02-2008 05:51 PM

Address sent...

Saml01 01-03-2008 12:05 AM


Originally Posted by Arkmage (Post 192510)
Address sent...

Lol. Time to send thousands of AOL trial cd's to your house.




































;)

Arkmage 01-03-2008 08:27 AM

Not a wise idea...

*points out "gun toting Texan" under name*

Anyways... I went by the autoparts store yesterday and had my codes pulled. There were no stored codes at all since I last cleared them (~50 miles). I'm hoping that maybe the last one was a glitch since my O2 sensor was bad and tripped the CEL, maybe it just tossed in the MAF code for good measure? :dunno:

Saml01 01-03-2008 10:05 AM

So are you or are you not getting a CEL?

Arkmage 01-03-2008 10:58 AM

currently I am not... most of the time I do not... it keeps popping on 5 miles from the inspection station. One of the codes that kept comming up was the rear O2 sensor, so I replaced it. The one for the MAF was shown as (Pending) which means it didn't trigger the CEL, but was present. The fact it was there would keep me from passing emissions, CEL or not. ATM, there is not even a pending code for the MAF.... which is strange.

Saml01 01-03-2008 11:28 AM

Strange. So go get inspected like right now. But I think you know that if you reset the computer and dont put a certain amount of miles on it, it wont link up with the emissions computer at the station.

240_to_miata 01-03-2008 12:06 PM

I found this article pretty interesting... I read somewhere that we have a hot wire MAFS...this describes the function of our MAFS

http://www.wellsmfgcorp.com/pdf/Counterpoint3_2.pdf

Saml01 01-03-2008 01:28 PM

^ We already knew that. Thanks for playing ;)

Arkmage, I sent you the sensor + a little something extra. Priority so you should have it fairly quick.

cjernigan 01-03-2008 01:51 PM

You can buy a OBD scanner at walmart, keep the receipt and take it back when you get done. They have two nice ones.

Saml01 01-03-2008 02:31 PM


Originally Posted by cjernigan (Post 192911)
You can buy a OBD scanner at walmart, keep the receipt and take it back when you get done. They have two nice ones.

How much are they? We dont have walmarts in brooklyn :(

Arkmage 01-03-2008 03:12 PM


Originally Posted by cjernigan (Post 192911)
You can buy a OBD scanner at walmart, keep the receipt and take it back when you get done. They have two nice ones.

might just do that... once I pass inspection I still plan to find a bypass so I can get that stupid hunk of useless plastic out of my engine bay.

Braineack 01-30-2008 09:37 AM

https://www.miataturbo.net/forum/att...1&d=1195664537


can one of you guys go back out and measure the resistance between 3 & 2. I'm trying to get the correct resistance values of the ECU so I can help you gets more accurate AIT values.....


please let me know what ecu 94-95 or 96-97

Arkmage 01-30-2008 10:00 AM


Originally Posted by Braineack (Post 206729)
https://www.miataturbo.net/forum/att...1&d=1195664537


can one of you guys go back out and measure the resistance between 3 & 2. I'm trying to get the correct resistance values of the ECU so I can help you gets more accurate AIT values.....


please let me know what ecu 94-95 or 96-97


? Won't that just give you the resistance of the AIT at whatever temp we are at? Do you also need to know the temp for this to be useful?

I'd be more satisfied if my damn coolant temp would read correctly. I'm at the point now that I'm thinking about adding a GM coolant sensor to the system and ditching the whole idea of sharing the stock sensor.

UPDATE: I'm lazy and busy and haven't made a lick of progress on the MAF issue. I ordered the parts from BEGi to stick my MAF back on the turbo inlet to pass emissions. After that I'll pull it back out and try again (when it's warmer out).

richyvrlimited 01-30-2008 10:03 AM


Originally Posted by Arkmage (Post 192435)
*edit* Scott, you know anything about the programmable outputs on the MS? Is there a 0-5V programmable output? I know there are 12V switched, but I think our odds of success are higher with a variable output since the ECU was complaining about lack of "circuit activity" rather that "broken circuit". I think it actually wants to see the airflow vary :(


The only available outputs are on/off type unfortunately. if there were variable outputs we would have some pretty cool options to play with :)


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