hesitation 2500-3500 code 20 and code 41

ASSISTANCE Stock Engine-Bay Components
1

Allright guys I have a 92 gs-r and it has a hesitation at 2500-4000 rpm. It is only part throttle hesitation and ti is caused by a lean condition (16.5-17.5 a/f on the wideband)
ecu p72 gs-r ecu
1st gen b16a motor with obd-1 sensors, injectors, distributor
things I have replaced to fix it.
plug wires
cap
rotor
3 diffrent distributor
another good working ecu
gs-r wiring harness
seperate known to be good o2 sensors.
codes 20 eld and 41 o2 heater.

From what I have seen in my searches the code 41 and 20 with this exact problem are related. My stock b17a ran just fine, my 2.0 ran just fine except for one time I had a low rpm stutter which ended up being a cracked spark plug. I pulled out my 2.0 vtec and I swapped in this b16a. My stock wiring harness had a few butt connections on it so I decided to use another stock wiring harness that ran fine in the car. I know the g2 tegs are not supposed to have an ELD on them but with 1200 miles on my other motor and this ecu p72 gs-r this is the first time I have gotten a code 20.
So what would the ecu look for at 10% throttle or under at 2500-4000 rpm that would cause it to lean the car out? The other thing if your gonna say O2 sensor, yes I am getting the code for the heater on the o2 but 1 I know all 3 O2’s I have tried worked fine before this swap and I just use the O2’s to keep the ecu happy because the actual O2 input the ecu reads comes out of the wideband. Before anyone says that is the problem it worked perfect before this swap.
Other things I have looked at or fixed. I have cleaned and tested all the grounds from the motor to the battery, I have rechecked every wiring harness plug and it is in the correct place. The tps is dead on .5 and 4.5 at wot. Ignition timing is 18 degress and the timing belt is on tdc.

2

I know that you have already ruled out the O2, but I kept getting a code 41 and horrible low rpm, partial throttle hesitation, in about the RPM range that you were describing.

I tested the O2 and it was working fine, according to my tests. But I tried everything and I finally replaced it, then the code went away and has been working great for months.

The other thing I would check that has caused a problem on my car, that may cause one on yours, check the opertation, and the wiring to your MAP sensor, make sure everything is tight and working correctly…

3

I haven’t ruled it out. But I know they were working before. What I think is happening is the heater part of the o2 is not working correctly prolly because of a short in the wiring harness and the ecu takes into account the heater is not working so the reading on the o2 is corrected for not being heated causing it to lean out. I am swapping back my stock harness that I know worked fine before the swap so we will see here in a few minutes.

4

well I changed harnesses and there was a short in the heater O2 wire so Now i do not have the 41 code…but the problem is still there. I swapped in this motor for daily driving and my most used rpm range has a hesitation.

Anyone want to buy a beautiful 92 gs-r with b16a ys1 trans action 1 md clutch act fly and some other extras for $4000 only thing wrong is a slight hesitation that no one knows how to fix???

5

:rant: :gunright: :mad: :mad: :mad: :mad: :mad: :mad: :mad:

6

I would come and take a look at it :wink: Are you in the boise area?

7

no cache valley area I live right on the border of utah and idaho.