doing the dx to si swap as we speak

[jpoenitsch]

wiring up the dx to si when I noticed that there is a sensor of some sort on the back and towards the bottom of the intake manifold with two wires blue/black and black and a plug comming off of it. The plug won't fit anything and I can't find any information on it. It looks like it measures pressure in the intake or something.

I looked at a few sites with pictures of si engines and didn't see this part on most of the manifolds. If anyone knows anything I would appreciate it. Otherwise I will just see if it works without pluggin it into anything.

 

[jpoenitsch]

So I looked over the diagram for the wiring and I think it is the fast idle control solenoid valve (blue 1 wire). I should connect it to the tandem solenoid control valve (orange wire) off of my dx harness. I am doing the swap as we speak so if anyone has any questions or suggestions let me know.

 

[jlicrx]

the fast idle control valve is on the back/driver's side end of the Si intake manifold - the DX wiring harness does not have wiring for this - do not connect the tandem valve connector to it - the tandem valve connector should be left unconnected - the fast idle control valve is only on 89-91 Si (not on 88) and was added to speed up idle at very low ambient air temperatures - it doesn't do anything until temperature is below -10C (14F) - you don't really need it, so don't connect anything to it and plug the vacuum lines - if you wanted to add wires back to the ECU to use it i could tell you how, but it is not worth the trouble