So I have a 91 Acura Integra with a B20B swap. I recently had a problem with the check engine light coming on. It ended up flashing code 43 the fuel sytem code. So I have replaced the O2 sensor, fuel pressure regulator, fuel pump, and fuel filter. I have also cleaned the fuel injectors with throttle body cleaner and removed the little screens inside there. When I replaced the fuel pump it took like $15 for it to start. And now when it gets to quarter of a tank on the gas guage it runs out of gas. The problem I'm having is that when I am driving the car its like between 2k and 3k RPM especially its like it hits a flat spot where there is no power and its like it is missing or cutting out or something but at higher RPM's it is fine. I am running out of options. Any ideas?

 

The ECU adjusts the mixture so as to cause the oxygen sensor to flip-flop. When the ECU is unable to make the flip-flops happen properly, and it cannot decide whether the problem is fuel delivery or the oxygen sensor, it sets a Code 43.

Does this vehicle have EGR?

 

I think so. Let me check.

 

Yes it does have an EGR valve. And I only have problems with the hesitation when the engine is warmed up. But when the engine is cold then it runs great.

 

Hesitations that are rpm specific are generally flat spots in the tps. Did you have the fuel gauge problem before you replaced the fuel pump

 

No the fuel guage was fine before I replaced the fuel pump. And do you think it could be a TPS problem? It's a wierd problem. Cause if I hit like 4k RPM it pulls harder than it does the rpm's below that.

 

What ECU are you using? Is your car an automatic?

 

Just using the stock ECU not chipped, I think it's PR4. It's a manual trans.

 

So now it gives me the code 1 which is the oxygen sensor code. It's like there is no power and it like sputters a little until 4k RPM then I hit 4k and it pulls. The check engine light comes on whenever it feels like it. Anyone got any ideas?

 

Have you checked the timming on the car?

 

No. I had adjusted the distributor though. To where it sounded like it was running better. I don't have a timing light. It's just wierd that is runs fine when it's cold and once it warms up it hits that flat spot.

 

Has anyone resolved this problem yet? Im having the same problem except it does the lapse when its cold. Once it warms up its ok.... I have a stock B18 manual. The tps has been cleaned and adjusted to drivability, the o2 has been replaced, the fuel system is good, timing is dead on, Maf is new, Dist cap & components good and adjusted with tps, plugs and wires new.... Im at a loss. Im always second guessing myself and I think I just dont have the tps a dizzy adjusted right but where it is makes it drivable.... is there any way I can confirm the tps and dizzy adjustment other than by ear? Is there anything I could be forgetting?

 

This a old thread lol.
But with the TPS you have to recalibrate it using a multimeter, by ear will not work, how did you do it?

Are you getting any codes?

 

I had code 43 too. I added a permanent fuel pressure gauge to my auto 92 Integra, it helps a lot with diagnosing. I had no fuel pressure. I soldered the main relay, and I had 12 volts going to the fuel pump so I changed the fuel pump. then I only had 32 pounds at idle in the car. still seemed very weak, and later I was driving and code 43 came back again, I changed the fuel pressure regulator ,cranked the car up and now I have 38 pounds of fuel pressure. I think the bad regulator was over working the pump that's why It burned out. hope this helps people in the future. (A couple of days later) .... ******UPDATE**** The cel code 43 for fuel system issue came back. I replaced the o2 sensor with a new one from autozone.($50) Now the code never came back, and I am getting better gas mileage now. I could also tell that the gas cap was good since I could hear a "Hiss" sound when I removed it. (venting the tank pressure) The car has better power now.