It's all fixed now and I went on a successful test drive. It was my first Link'd Miata drive in nearly a year. Man it was sweet. And I never have to take it out, thanks to the OBD1 of my 95. *megahappysigh*
I re-soldered the two wire connections on the IAT sensor and everything worked again. Not difficult, but not as easy as fixing a ground... Thanks SO much for the help, Ray. I'm archiving this email thread. Adam On Sat, May 2, 2009 at 10:21 PM, Ray Ayala <[email protected]> wrote: > The 24*C initial temperature is the ECU's default start-up temperature in > order to enable starting a cold engine when the sensor isn't working. > Eventually the sensor signal is timed out if it's not being received and the > display goes to 100*C as an error indicator. The next thing to check is the > voltage at the power steering pressure switch connector while the air temp > sensor is disconnected from it. It should be a steady +12v when the ECU is > powered on. If not, there is either a wiring error or an ECU hardware > error. > > ----- Original Message ----- > *From:* Adam Wolf <[email protected]> > *To:* Miata Power List <[email protected]> > *Sent:* Saturday, May 02, 2009 8:21 PM > *Subject:* Re: Obiwan into a 95 - in progress > > http://forum.miata.net/vb/showthread.php?t=212070&highlight=link+IAT > > How odd. This is the EXACT behavior I'm seeing with my temp sensor, down to > the 24*C initial temperature. I wonder if I need a new sensor? > > I was never able to see the 6v, Ray. I got rapid millivolt fluctuations (8 > to 400) and then a steady 110 millivolts and then nothing. I was never able > to see more than about a half volt come out of the sensor. > > Adam > > On Sat, May 2, 2009 at 6:24 PM, Ray Ayala <[email protected]> wrote: > >> The sensor signal switches rapidly between ground and 12v (equal time on >> and off), and the frequency of the switching is proportional to the air >> temp. So if you look at the signal with a good voltmeter it should always >> appear to be 6v. When the sensor stops working perhaps the value >> observed will reveal something about the cause of the problem. >> >> ----- Original Message ----- >> *From:* Adam Wolf <[email protected]> >> *To:* Miata Power List <[email protected]> >> *Sent:* Saturday, May 02, 2009 5:11 PM >> *Subject:* Re: Obiwan into a 95 - in progress >> >> Thanks Ray! I actually managed to solve it myself a few minutes ago, but I >> can imagine your info coming in handy when I actually go for a test drive. >> >> For future reference, the FM OBD2 rewire document is incorrect. It has you >> wiring the tack to pin 1f on the 94/95s. That pin is not actually used for >> anything according to the factory wiring diagrams. The correct pin is 2i on >> the 94/95 input side of the harness. The doc did indeed have the 4L pin >> correct, as Ray emailed just now. >> >> SO! My next problem: anyone know why the air temp would start off correct >> at key on (24* right now) and change to 100* magically after about 7 >> seconds? This is a few seconds after the fuel relay clicks off. And nothing >> I do makes the signal come back. I've redone the ground and verified the >> pins are correct on my magic wiring harness. I've plugged my multimeter into >> it and get a stable (after a moment) resistance value. >> >> Adam >> >> >> On Sat, May 2, 2009 at 4:52 PM, Ray Ayala <[email protected]> wrote: >> >>> If you've got 4-wire coils then you can connect the tach to 4th tach >>> wire of both coils. If you've got 3-wire coils than you'll need to connect >>> the tach to the obiwan's pin 4L. IIRC some 95 tachs (there was a mid-year >>> change) may need a 680 ohm 1/2w resistor connected to switched +12v when >>> used with the obiwan. The air temp sensor needs to be connected to pin 3P >>> (via the power steering pressure switch wire). >>> >>> ----- Original Message ----- >>> *From:* Adam Wolf <[email protected]> >>> *To:* Miata Power List <[email protected]> >>> *Sent:* Saturday, May 02, 2009 3:26 PM >>> *Subject:* Obiwan into a 95 - in progress >>> >>> Howdy Power List, >>> >>> A while ago, I lost my 97 in a freeway accident and got a nice, fresh 95 >>> to replace it. So I ripped the Link out of the 97 and am in the process of >>> putting it into my 95. It's going well. I had Boomslang make me a custom >>> wiring harness as the exact reverse of this: >>> http://www.flyinmiata.com/support/instructions/ecu/OBD2_rewire.pdf They >>> did a great job and charged me $150, $25 over their pre-built Honda >>> gender-changing harnesses. I was stoked. The harness is beautiful. >>> >>> The good news: it fired up on the first try and ran smooth with my old >>> N/A values. I seem to have an air temp value of 100, but I'm not concerned >>> about that. I've fixed that problem before. >>> >>> The bad news and the reason for my email: I have no tach. I have RPM >>> numbers on my keypad which rise and fall correctly, but my stock tach is >>> dead in the water. I've read on Miatanet that the 94-95s get their signal >>> direct from the coils while the 96-97 get it direct from the ECU itself. I'm >>> unsure which wires to fiddle with on the ECU. Anyone ran into this before? >>> >>> Thanks! >>> >>> Adam >>> >>> ------------------------------ >>> >>> _______________________________________________ >>> Miatapower mailing list >>> [email protected] >>> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >>> >>> >> ------------------------------ >> >> _______________________________________________ >> Miatapower mailing list >> [email protected] >> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >> >> > ------------------------------ > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > >
_______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
