I have a DIY SRI similar to Lyon's, with the MAF intact inside the cut out section of the factory airbox. I also have a custom 2.25" catback exhaust installed from a muffler shop.

I installed Denso IK22 Iridium spark plugs about two days before now. They are the IK22's, so they are one heat range colder than the stock IK20/NGK plugs. I don't think this could be the problem, but I thought it was worth mentioning for the sake of mentioning.

I was in a parking lot, and it's about 30 degrees outside. All of a sudden, a CEL comes out as I start the car. Which leads me to believe it's not exhaust/O2 sensor related, considering I had a 1993 Del Sol that would require the O2 sensor to properly warm up before it would throw a CEL for an O2 sensor.

The strange part is, the car ran perfectly fine. It didn't seem sluggish, it was it's usual self.

Could it be just the fact that I have this SRI installed (The filter is located in the section of the engine bay behind the air induction scoop on the underside of the hood--you can touch the filter, and it's still cold.), and the IAT sensor reads a parameter outside of stock spec, and causes a CEL?

I have not disconnected the battery for 10 minutes yet and let the car idle. I plan to do that tomorrow first thing and see if it eradicates that problem. Just wanted to know if I was on the right track, and don't have to worry about any other concerns. I also found a thread on how to check your own codes without a scan tool, but I am a little concerned on how that goes without damaging something. I have seen a similar problem with intakes and CEL's, but I have not seen one like this where the car throws one after several hundred miles of driving with the intake installed, and throwing a CEL as soon as it's started. Considering I've reset the computer when I installed the intake, and when I had the exhaust done.

 

Update:

I reset the computer by unhooking the negative battery connection for 10 minutes, did the idle re-learn in 20 degree weather outside, and the CEL went away.

 

How do you check codes w/out a code reader? Point to thread?

Check you gas cap? With your eliminating the CEL, if issue exists it will return, but I'm still interested in checking code question.

 

Disconnecting the negative cable only erases the stored random access memory which is the timing correction, short/long term fuel trims and any other correction made by the ecu. You still need a scan tool to make sure the code is erased. There are 5 perimeters that the ecu needs set for the car to pass emissions and to run right.

 

I have not checked the gas cap, but come to think of it, I had filled up the tank that night just before it came on.

And as for the computer, I'm aware, but I would think it would come up with a CEL since the conditions were about the same, but the parameters weren't set.

Then again, I'm just a white teenage boy with no job and still in high school. I could most definitely be wrong. I will go check that cap.

 

https://www.fitfreak.net/forums/fit-...ight=diy%2Bcel

it's super easy..just short the same connectors via a paperclip and turn the ignition to ON II (don't start)

then the CEL will flash... write down/remember how many long flashes (first) and how many short flashes (second). consult the list in the thread for what CEL code is throwing.

worked for me today