So now after my swap in complete I get the check engine light coming on once in a while and it's giving me a Code 43 - Fuel System Supply. I'm really not sure how to diagnose this one because other than a crappy idle the car runs great!

There was some talk about a bad o2 sensor in this thread;
https://honda-tech.com/zerothread?id=2342352

and this got me wondering... I'm using the o2 sensor that came from my old D15 on my '96 B18b using an obd0 PR4. Does the Teg ECU want to see a TEG o2 sensor or is there something else going on?

 

Well I guess it cant hurt to try it. Plus im sure its a old one, and could use some replacing.. haha

 

same code here and o2 sensor was the fixed.

 

Well, I'll see if I can find one for the integra and see what happens after that. Thanks guys!

 

The o2 sensor for a 88-91 crx is going to be the same for a 90-91 integra. The 92-95 teg is obd1 and 4 wire. 96+ is obd2.

I just think your stock o2 sensor is bad, try replacing it with a known good one from a 88-91 honda and see how that works.

 

Does this "Fuel System Supply' code have anything to do with the fact that I'm still using the 1.5L Fuel pump to supply by B18b? Should I have upgraded the fuel pump when I did the swap?

 

It's finally time for me to update this thread. A while back I pulled out my trusty multimeter and went to town. I measured the voltage coming out of the O2 sensor and was getting a pretty much consistent 0.7v, I even tried pinching the fuel return line and there was no change.

I picked up a new 4-wire Denso sensor on ebay and tried to wire it in. The 4-wire was recommended to me from a good friend and long time Honda employee because the sensor was so far from the exhaust manifold. As it would turn out the brand new sensor that I installed was reading a constant 0v. I double checked the wiring, and checked it again. I even reversed the wires just to see of it would make a difference, but no luck.

So, I went down to the local pick a part and grabbed a 1-wire Denso, a 1-wire NTK and a 4-wire Denso for $20. I came home and installed the 1-wire Denso...

I checked the voltage out of the sensor and was getting the usual fluctuations in voltage as to be expected, so the sensor was ok, but when I wired it to the harness it went to 0v. After running a new wire to the ECU and clearing the codes, everything is working just fine. I took the car out for a half hour drive and there are no codes to speak of.

So, it looks like the problem is solved.