1992 civic hatch cx
d16y5 on stock P28 obd1
Im getting CEL codes
10 - Intake air temp sensor (not running one)
41 - Primary oxygen sensor heater

Whenever my car comes to a stop when warmed up it will have a rough-low idle as if it wants to stall and die until you turn on the heater full blast or turn off and on the car, i’m not running a Intake temp sensor right now but i do i have brand new o2 but why would i have code 41? is it because im not running an iats is this what is making my car idle like this? what are my options to fix this? I do plan on getting the car chipped and tuned in the future or would my issue just be me running on the stock p28 map? any help very appreciated thank you guys.

 

When you combine the wrong parts, bad engine behavior is the result. First, the P28 is not the correct ECU for a D16Y5. That engine has absolutely no business being in any other chassis other than a HX... but I digress. Tuning will allow you to run the P28 with alternate programming and make things better. Notice I didn't say adding a chip with a canned tune... tune your combination on a dyno. Install the IAT sensor, nothing runs perfect with codes. If you didn't add the necessary wiring to the chassis harness to operate the O2 heater circuit, you will get a code 41. Remember that the CX has a single wire O2 sensor originally since the sensor is mounted very close to the cylinder head... so your 4-wire O2 sensor doesn't have all of the appropriate connections if you simply used an EX engine harness and plugged it directly into the chassis harness plugs at both shock towers.

You have work to do.

 

Thanks i did actually have a iat this is what it looked liked; replacing it with a new one. now about my o2 what we did was wire it directly to the ecu pins so it’s not even attached to the harness, it’s a 4 wire so would it still be the issue that it’s not a one wire? thanks.

 

How specifically did you wire the O2 sensor up to the ECU ? What wire positions did you connect the O2 signal wire and Heater Control wires to ? What did you do for the 12V+ and Ground wires that need to be connected to the O2 sensor ?

 

Oh yeah... the IAT sensor is toast. Good job inspecting that and figuring out that it is burnt and shorted out. Replace and move on.

 

Thanks my friend did the o2 so i’ll have to get back to you on that but could you also help me with identifying these plugs i know if you plug them incorrectly it will just burn the iat sensor again by sending too man V’s right?; i think the white plug (green/white & yellow/red) is the iat sensor and the darker plug (solid red & yellow/black) is for the purge? thanks.

 

help me with identifying these plugs i know if you plug them incorrectly it will just burn the iat sensor again by sending too man V’s right?; i think the white plug (green/white & yellow/red) is the iat sensor and the darker plug (solid red & yellow/black) is for the purge?

 

Purge control solenoid valve: Yel/Blk wire and Red wire

Intake Air Temperature sensor: Grn/Wht wire and Red/Yel wire

 

That's correct... the IAT plug is the white one (red/yellow and green/white wires) and the purge control plug is the grey one (red and yellow/black wires). The IAT circuit is only a 5V sensor, whereas, the purge control circuit is a 12V sensor... and if you plug the purge control clip into the IAT sensor, you get the exploded tip that you took the photo of in your first pic because putting 12V on a 5V sensor is bad.

 

This is why posting the same issue in multiple threads is rude and unfair to future readers... I have answered in your other thread and tech8 has answered here. tech8, would you please merge these two threads for this rookie ?