Light-to-medium modifications always = CEL or not?

[Rice Over Wheat]

Ok, I've been getting mixed feedback from many different tuners regarding CEL lights on a light to heavily modded DSM. Half tell me that due to greatly increased air and fuel flow over stock specifications, this throws the numbers way off the ECU maps and therefore it's common to always have a CEL. The other half tell me that this is not the case and that you should never have a CEL, regardless of the mods done to the car. Even a pro told me this.

I'm asking because my car runs perfect after having it tuned with an SAFCII, however I do have a CEL light that pops on occasionally. When I reset it, I may be driving around for 15 minutes or so and it returns. Like I said, I can't detect anything wrong with the car so I don't know what to believe.

How many of you are driving around with CEL's that don't seem to pan out to anything actually wrong when you run the code and check it out?

 

[SpeedFreak03]

I personally don't own a DSM, but what is the code you are getting? A lot of codes are just "warnings", but they won't affect performance. Then some codes DO affect performance, so I guess it depends. I'd say the most common CEL for a lightly modded car is for the rear O2 sensor, most people don't hook it up when they do their exhaust.

 

[TurBoGs-T]

I had mine or for awhile and it was 3 stupid codes. All i could remember was one being a Wastegate code.. I think it just comes on for the hell of it most of the time.

 

[Rice Over Wheat]

I think one of the codes was P0505 Idle control system. My car used to have serious idle problems before I had it tuned to the SAFCII, but now it idles fine. I've heard from a lot of people that they can never get the CELs to go away.

I still always get a CEL though. Even if it's nothing major or an underlying problem, it sucks because that means I'll have to periodically check my codes just to make sure something serious doesn't come up.

 

[Sephroth57]

it depends what the CELs are really, some might mean you actually need to maitenence something like replacing your fron o2 sensor, some might just be crap warning codes or something you obviously know, like your rear o2 is dead cause youre running no cat. i always have a CEL on from my rear o2, ocassionally get the Idle Speed Control one too. basicly its something you gotta live with although there are ways to make the rear o2 one not show up, and the ISC one really isnt BS and means you should replace your ISC unit eventually

 

[Rice Over Wheat]

Ok, the rear O2 makes sense since I'm running no cat. Yeah I guess I just have to live with it...better invest in pocketlogger now I guess.

 

[leet]

Ok, the rear O2 makes sense since I'm running no cat. Yeah I guess I just have to live with it...better invest in pocketlogger now I guess.

ROW,

Some people (myself included) have been able to run a test pipe, and not get a CEL. However, others haven't. That seems to be a 50/50 chance sort of thing.

 

[TheTSiGuy]

When i had my full stage 1 setup on my 1g (est. 290-300 whp) I never got a code.

I had a 2g MAS, and it was wired correctly, and an AFC to handle all airflow modifications. on a 1g, if everything is done right, nothing will show.