FlewByU352

So recently my CEL would come on randomly, it would happen at different driving conditions, throttle input, and RPM's so it's hard to pinpoint what exactly is causing it. Now I figured it was my O2 acting up. So I changed it for another used O2 I had that did work before. Seemed to cure it for a bit but the random CEL continued. So maybe it isn't an O2? I know before when I had a O2 the CEL would be on at all times even with a restart. I would do the jumper with a paper clip to see what it flashes but I didn't think that could be done with the car running. I always did it with just turning the car on before ignition to get the blinks. I can't imagine it being stored only because it goes away as soon as I turn the car off and won't come back on until another random time. Do I just wait for it then drive my car to the autoparts store to throw a scanner on it as the car is still running and the light is on? Or do I throw in another used but known good O2 I have laying around to try and narrow that out. Still getting 30MPG so there is no drop in mileage.

HondaPartsHero

Year/make/model?

FlewByU352

98 Integra Type R

93coupegsr

In my car I have hondata s300 and when the cel comes on just means i need more oil cause its low.. and before that I had the same problem youre having but it was my o2 because I didnt have one. Hopefully you find out the cause

Relic1

jumper can be added while running, all though be sure to turn the car off after reading the codes and removing the jumper.
since you're OBD2 you can also read the codes via scan tool, unless you're tuned with OBD1 or running a JDM ECU then it's jumper only.

FlewByU352

WTF got 1 long flash then time went on no light then 1 long flash more time went on with no light then 1 long flash before I unplugged it. So that is just 1 long flash being 10 correct? Meaning IAT?

HondaPartsHero

Go to an autoparts store and have them scan it. If it has thrown codes it should have stored them in it. Then report back.

FlewByU352

Reporting back with nothing. The scanner just kept saying error could not connect even though it was connected and getting power.

Relic1

that means IAT problems can be random, since the ECU doesn't know if it really is -40*F or +200*F, yes we know it's not really that, but the ECU can't assume.
possible causes:
-IAT and EVAP purge plugs switched (very common swap problem, approx same length wires, same area of harness, same plug)
-bad wire for the IAT
-bad sensor

if you can datalog see what the IAT sensor is telling the ECU.
You can check it with a volt meter as well, but I don't remember the voltages off the top of my head.

FlewByU352

Yeah but the car has been fine for 7,000 miles nothing changed besides the header. I even did a track day with the header and everything was fine. Then it randomly came up. Figured it was the O2 I got with the header since it was spliced into a O2 plug, so I put in a used Denso that I knew worked prior to. Everything seemed fine then the light came back. If the IAT and EVAP plugs were switched it would have burnt it up long ago. I even data logged a few weeks ago and IAT read perfect. Maybe it is time to throw the S300 on this car and see if the problem will come up and then we will know for sure what it is.

93coupegsr

I have a feeling its the o2 cause mine did the same and once I put the s300 in thats what mine read but we disabled it.

FlewByU352

Finally got it to come on when I had my computer in the car with me, kept the car on, plugged it in to datalog and check for errors the O2 sensor was to blame. I also did a hard shift and cracked my aluminum radiator, how that is possible IDK but new parts on the way lol.

Relic1

only way this is possible... what you thought was a long flash, was really a short flash.
I've been there and done that myself.

shifted wrong and cracked the radiator...wtf?... since the radiator is mounted to the chassis and only the hoses connect to the engine/trans... are you running seriously stiff radiator hoses, or does the chassis flex that much?

FlewByU352

I didn't shift wrong I shifted hard and it dead hooked lmao. I heard a bang not from the engine or trans. When I stopped the radiator fan kicked on and I smelled coolant. Drove it home, popped the hood, said WTF mate.