MAF orientation? RPM signal?

[Mirage]

Hey all. With my car being down for a while, I'm getting to do what I've been wanting to do for a long time. Install waiting parts. I'm just about finished installing my MAFT in a blow-thru, but have a generally stupid question. I know that the MAF has a flow direction, but does it matter if it's "upside down"? I have a '90 and the way my IC pipes sit, the MAF connector sits right where the throttle cables sit making the cables have a weird angle. If I install it almost totally upside down, it fits perfect. Go figure. Would it affect the measurement at all if I use it like this? Also, where is a decent rpm signal without having to pull it off of the ECU harness? Keep in mind I have a '90. I was searching through the backup CD, technical manual and my Haynes (I know, I know. Get a real manual) book and found no conclusive answer to having a "clean" signal (not doubled up).

Marcus Martinez

[v413nc3]

it only matters which way the air flows, you can mount it upside down.

[Reef187]

I believe you should be able to tap into one of the wires from the cam angle sensor for your RPM line.... That's where I have mine and it seems to run fine, but mine's a 92 so I'm not sure if they're different.....

[v413nc3]

tach signal should also be available from the coils

[Mirage]

I would assume that the wire I need to tap is the wire that is the tach interface output? I'm assuming that this is a "clean" source other than straight at the ECU. I was getting ready to tap that wire, but thought I'd try to find a better (closer) place. Seeing that the car isn't startable to test for a clean signal, I'm going off of what you guys say. So point me in the right direction. :)

Marcus Martinez

[DlandryTSI]

Really all that the tach signal gives you is another fuel management device. If you already have an s-afc you can leave the rpm lead disconnected on the maft.

--Dave

[Mirage]

Yeah, I *could* leave it disconnected, but I want to keep my options open ;) . I would rather use the thing to it's fullest potential instead of it "just" translating.

Marcus Martinez

[Reef187]

The sheet that came with my translator says to use the black wire(pin 2) on the CAS, or the TACH signal from the Power Transistor module(white wire) can be used. Just so long as the signal is a clean, logic level signal. No coil terminals. The CAS is where I have it connected and it seems to work just fine, course tuning seems to be a pain, probly has somethin to do with my injectors throwin an error code, but who knows.