I'm going over my Edelbrock 3860 manifold, and to my knowledge, it accepts the 9th injector. I was planning to just block it off, but while going over it, I could find where the hole went. Like how does the injector pulse get into the engine? it look like it just dead ends.

I have an 89 so I don't have it, need it, nor have i seen a manifold with it to look over.

 

I always wondered that myself. On a stock intake, there is a small hole drilled in the floor of each intake passage. That leads to drilled passages under the manifold. I believe that is where the cold start enrichment fuel enters the flow path to the cylinders.

 

I thought it went through the small "5th" runner tube on the drivers side. 90-92 SD runners don't have it. The passenger side "5th" runner I think is for the egr and that's why both MAF and SD both have it. I could be wrong since I don't have a MAF manifold in my face.

 

Aliceempire, you are correct. The passenger side 5th runner is for egr. But the driver's side 5th runner tube is to allow idle air to pass from the throttle body, go under the plenum through a cast-in passage, then out the driver's side of the plenum, down to the intake manifold. Later designs, 89 - 92, have a notch behind the throttle body where the idle air comes out to allow it to pass into the plenum immediately behind the throttle blades. That's why later style plenums do not have that cast in passage going to the driver's side, no 5th runner needed.

 

Ah ha, that's right. I even knew the plenum was different for that reason....it would really help if I looked at the older manifolds in my stash....I even skipped a year, I blanked that 89 have the newer plenum yet no cold start, I'm losing it.

 

...interesting....thanks guys.