Hey Fellas,



You know how most of us guys have the CEL show up once we have our headers installed, well some of us put the CEL eliminator and some of us don't right ..

I was wondering, though "technically" nothing is wrong with the car when the CEL displays, could this affect a tune? Because from what I gather, wouldn't the ECU go into 'safe-guard' mode and not allow the ecu to perform to its full ability restricting timing, ignition etc.

I just figure the ECU is being told something is wrong and therefore go into safe-mode, undermining the car's ability.

Discuss please

 

A CEL from cat inefficiency doesn't change anything, it's merely there as required by law to notify you that your catalytic converter isn't working at full efficiency. All the important work is handled by the first O2 sensor. If your car were in limp mode, you'd know it. You would have no power and wouldn't be able to rev above 3k.

 

Thanks for that otter, so the CEL is coming from the second o2 sensor and this merely has no affect on the car's ecu other than letting the driver know that there is a cat inefficiency. Am I right in saying that?

 

it will go back to the default fuel trims, if I am not mistaken. still little to no affect, as your fuel trims have only changed due to the tune on your piggyback anyway. well, unless you didn't reset the ECU before tuning the piggyback(kind of dumb to install it with the battery hooked up though)

 

i have a cel from "poor egr flow" and it does not affect me any bit

 

lol, trukero

 

just make it no flow at all.... no ah prendio CEL por ahora

 

wise asses

 

well, I can't tell if you are playing on teh OT games or being serious the MAP sensor checks the EGR valve though, that much I have come across in my research.

 

no games is a real set of codes thats bugging me

P0401/403/404

EGR flow - insufficient, circuit malfunction, undetected range

(remember i dont have an egr, plan to put it back when i boost it up)

and again, no effect on performance
this codes are usual if and when you eliminate totally the egr, i didnt blocked it, i eliminated it

 

so there is no circuit, that explains the codes for sure

I guess it's not really bugging you then I wouldn't expect a decline in performance from the EGR circuit, the MAP circuit doesn't put it in limp mode either.

which gives me an idea...

 

Are u sure about this? I thought the ECU would put the car into a "safe mode" untill the CEL is fixed. I'm asking because I have a header and the CEL only goes off once a month and I can tell the difference in power... maybe it's just in my head =/

 

Yeah thats what I thought, but apparently the second o2 sensor does not affect the ecu. The first one does.

Mine is constantly on, so I'm going to speak to a tuner relating this and have some AF pulled up on the dyno!

 

All that will happen is that the car will recieve alot more air therefore causing it richin up. Your ECU will go into default mode with cat code do to wrong reading from O2.

 

If you have a scan tool or computer to hook up to the car you can monitor both Fuel trim 1 and fuel trim 2 which should be Forward and rear o2. If you have a scanner for Mitsu. then it should read Ox. Sen.1 Ox. Sen.2 etc. Both send info to ECU. I would check it and also do have the spacer for rear o2?