(edit comment: This thread was originally titled “name this sensor” because I had no clue what I was looking at back there on the intake manifold. I now know it is the cold start injector. Hopefully, retitling the thread will help others who may search this subject)


While I was taking stock today of the damage I did yesterday breaking every hard vacuum line on the front area of the intake manifold, I examined the area at the rear of the intake manifold.

Back there I see a sensor I don't recognize.
Located right next to the distributor shaft on the driver side.

The sensor has what looks to be some sort of hard greyish-color PVC vacuum line, which runs from the sensor to some very-difficult-to-see fitting located somewhere in the center of the labyrinth under the plenum.

Electrically, there is a two-wire connector that attaches. That area is a real mess from oil-leak around the distributor shaft. So, its hard to say 100% what the colors of the two wires are. My best assessment is that the wires are red and yellow.

Any information about what is this sensor would be greatly appreciated.

Specifically, I'd like to know:
1. What is this sensor generally?
2. Where do the two wires go (just to some dash gauge, or to the ECM, or to something else altogether)?
3. Where does the vacuum line go? (Why so far into the labyrinth if all it needs is manifold vacuum?)
4. How incredibly screwed will I be if I break this vacuum line? (This line looks like it has a very unique connector at the exposed area at the rear of the manifold. I can only assume that the impossible-to-see connector under the plenum is equally unique.)

I added a yellow line to show the path of the greyish vacuum line as best as i could get my camera angled.

Apologies for the filthy motor. Last year, I did install completely new distributor (which came with a new O-ring installed), but I didn't clean the area up at the same time. Frankly, there is so much fresh-looking spew back there, I wonder if the new distributor isn't still letting oil escape.

 

I'm thinking its not a sensor after all.

The "cold-start injector" perhaps?

And that grey line I thought was PVC may actually be a metal line with some sort of "plastic-ey" bonded coating on it?

Indeed it does help to "read the manual." Although, my ability to understand the manual is highly questionable.

 

The cold start injector is the part fed with fuel in metal tubing from fuel rail. Get its power via cold start switch in front of engine next Coolant Temperature Sensor.Not sure what the black plastic part is.

 

Just the cold start switch! The tube is just metal with a kinda plastic coating. Black plastic is just the connector plug for the switch. Try not to break it because you'd HAVE to find one off a junkyard 2.8, it might be specific to f-bodies too. You have to be careful with the fitting where it screws into the fuel rail, they can cross thread, and the fitting for the CSI can break and leak fuel. Been there done that haha

 

Hi W.E.G. ,

Yes indeed , that unit you see in the back of the lower manifold is the cold start injector . In the first picture I posted , if you zoom in , it's the item directly to the left of the radiator fan laying on the floor . In my second shot you will see where it is screwed into the fuel rail that supplies it and the other 6 injectors with fuel . Now the CSI switch (seen in picture #2) will be the larger of the two sending unit looking devices screwed into the lower manifold at the front of the engine towards the driver's side (the other smaller sensor being the one that tells the ECM the coolant temp so it can mix the fuel properly depending on engine temp) . The CSI switch measures the coolant temperature and only allows the CSI to function on cold starts only , acting very much like a choke on a carb equipped car (cold engine = choke closed , warm engine = choke open)

 

Thank you all for the confirmation!

I figure if I’m going to have any hope of successfully tinkering with this motor, I had better be able to identify, and understand the workings of each component.

I may never get a handle on the logic-paths of the inner workings of the ECU. But understanding each physical component has to happen.

Today I will attempt to rebuild the vacuum harness I destroyed during my recent exploration. Sometimes I guess you gotta retrace your path before you can go farther.

 

Found a pic of the whole cold-start injector apparatus on Google.

This supposedly came off a Fiero.
Except for the shorter run of the feed-line to the attachment at the fuel rail (my feed line seems to go deeper into the labyrinth under the plenum), this bit it looks like a ringer for what I see on my car.
Pulled pics from this link: http://www.fiero.nl/forum/Forum2/HTML/134297.html

Posted for visual clarity of the subject.




Here, with the distributor, and injector's electrical harness removed.