Hi Everyone.
I recently bought my first honda. Its a 91 CRX Si with a b20z2. The car is rough and does need work. I noticed the other day that the MAP sensor on the throttle body was disconected. I Eventually found it connected to another MAP sensor thats was just laying on top of some wires with some vacuum lines running to the intake manifold and the fuel rail as seen in the pics below. I am confuesed to which sensor i should be plugged in to.. i am not very familiar with electrical work yet.. I feel that the guy that did this swap did a sloppy job and just threw everything together
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As long as they are both connected to the intake manifold, it shouldnt matter which one you use.

But, I personally would use the one on the TB, and remove the other, while cleaning up some of that vacuum line mess.

 

Thats what i was going to do.. should i just block the vacuum lines that were connected to the other map sensor and just remove that sensor? i Also was wondering if anyone would be able to tell me why every once in a while the car seems rev limited to a low rpm when driving. Thanks for the reply!

 

Yes remove as much excess as you can.

And check your TPS wires, loose connections there will cause it to go into 'limp mode' 3k rpm rev limit.

 

In the first pic, directly between the floating disconnected MAP and the FPR, there appears to be vacuum port on the intake manifold that has a small screw in it.
Not that black vacuum line that has a screw, but the little port on the intake manifold right above the throttle cable bracket.
The line coming off the disconnected MAP goes to a T-fitting. The T-fitting goes to the FPR and the intake manifold.
You should disconnect it all and just run a line from the FPR directly to the port that has a screw in it. No T-fitting, no caps... nothing - just a short single line from point A to point B.

In your second pic, you have the purge-cut solenoid (for the EVAP system)with a vacuum line that is running off out the side of the pic.
The line is labeled "7". Where is this going off to?
It is supposed to be going to the charcoal canister- which it very well might be.
The problem here is that the bottom of the purge-cut isn't hooked up at all.
This should be connected to the port on the back of the intake manifold that currently has the FPR, T-fitting, spare MAP mess.

Also, directly to the left of the purge-cut solenoid, mounted to the same firewall bracket, there is another MAP sensor from the stock engine.
Congrats on the 3 MAP sensors!

So... back to that black vacuum line with the screw in it... where does that go off to?

found a diagram

 

^ That diagram is correct. I would remove everything and start over.

 

Ok what you are showing here is really helpful! The diagram makes it easier to understand. i got rid of the extra map sensor and connected the line from the intake to the purge cut? But i can connect the FPR to the intake without the port There.. Is the a way to get a replacement port? I also looked the charcaol canister. The lines look correct to me. One going to the throttle body, one to the purge-cut, and the other going to a line on the firewall.. and the line you were asking about with the screw in it just goes straight to the manifold and thats it.

 

BTW where did you get that diagram

 

Everything looks good, except for the FPR. Where is that small line going? The one going from the top of the FPR.

 

EDIT: Removed.

If 4drEF is correct, then I was way off. I was under the impression the B20 was much more similar to my B16 and the B18A/Bs I have seen.

 

What valve cover is that?
I believe the B20 has the PCV on the valve cover like this


Also, below is what the FPR line should look like
Are you saying the nipple coming out of the intake manifold it gone?
If it is gone, you can drill out the old one and tap for threads to install something like this
http://www.mcmaster.com/#brass-push-...ttings/=sj97r7

If you can somehow pull the remaining bit out (possibly just pull on the screw that's in there or use an 'easy-out'), You can check around for a carburetor shop and see if they have the press in type... or do some searching on the internet for someplace that sells them (I'm not having any luck).