Can someone tell me if this FCD is s4 or s5??

[FerociousP]

I got it off an 87 that the guy was trying to do an s5 swap on... but I'm unsure as the guy was trying to wire the injectors without putting resisters in so I don't know if the correct FCD was purchased. Is there any way to tell??

Do I need to open it up and look inside?? Can I tell if I use a multimeter?

http://picasaweb.google.com/lh/photo/g5oP2sGVO-2WFl-1dgZDMg?feat=directlink

http://picasaweb.google.com/lh/photo/FXqqI3PoLlAAsYxFFfuzJA?feat=directlink

http://picasaweb.google.com/lh/photo/v4Nc7RhKb1NAsuBskmewFw?feat=directlink

http://lh3.ggpht.com/_DOIP7bvsJCI/SeKnTbJHiPI/AAAAAAAAAOE/m3mb7ubZAVM/s1024/DSCN1860.JPG

[vex]

test the injectors. If he wasn't using a resistor pack then it's S5, if he was using a resistor pack it's S4

[FerociousP]

??

The injectors are s5.... he just didn't know what he was doing, which is my concern

[vex]

ahhh shaz bot.

Hmmm, my thinking/understanding of the FCD is it keeps the ecu from reading the voltage of the MAP as being maxed out and reaching the 8psi cut off. I may be wrong on this assumption, but isn't the MAP voltages from both the S4 and S5 the same?

[FerociousP]

I've always heard people sell them as s4 or s5 so I'm looking for confirmation... anyone?

[vex]

Racing beat sells two different ones, same picture, but different numbers and different price. I think your best bet would be to double check the FSM for the S4 and S5 and see how they check the MAP's are inspec or not. I'll look into it too.

They are different.

Page 83 of this PDF: http://www.rotarycarclub.com/rotary_forum/showthread.php?t=7591
States that at 100mmHG you should be getting 1.9-2.1v. Compare that to
Page 78 of this PDF: http://www.rotorwiki.com/images/f/fd/04b_fuelandemissionsturbo.pdf
states that at 100mmHG you should be getting 2.0-2.5v.

As far as that tells me they're using a more precise control unit for the S5, the resistor type should still be the same, ie: Linear or Log.

However, readings at the cut off pressures may be different values and you should check by putting the sensor to 8.6psi and seeing the voltage you get out. Once you know that voltage, compare it with and without the FCD, the voltage should drop to a certain percentage. This should let you know what your FCD is for.