Another Engine Light question

[Ex-Rolla]

Hey people,

I know there have been a gazillion check engine light threads, but nothing was mentioned that describes the problem i'm experiencing... Here it goes.

If my car is idling for about 10 to 15 minutes (i know, i know), the engine light comes on. After roughly 24 hours it disappears. A week later, if i find myself idiling for 10 to 15 minutes, the same thing happens. This has been happening for quite a few monts now.

Here's what i have installed... Mazdaspeed exhaust and the Tech-Racing CAI.

Here's what i've checked;
- Plugs look great
- Air filter is clean (cleaned it when it first happened)

One thing i noticed is the rubber seal on the MAF has somewhat comeing apart leading me to believe it may be source of the problem.

I have also taken the car to the dealer, but was told they can't do anything if the light is not there and to return when it reappears, but i can't leave the car for 2 or more hours.

Can any of you shed some light on this? or should i just take it to the dealer (again)

Thanks! :)

[Noisy Crow]

The codes should still be in the ECU, so I am surprised that dealer can't pull them.... now I can say for sure that this is true for the Mazda3, but every other car I have had keeps the most recent set of trouble codes stored, even if the fault goes away. Only manually clearing them or a new fault occurence will clear them...

Otherwise, there are several people on the board with ODB readers... maybe you could borrow one for a while....

[Houndskull]

that never happend to me but when i went to the dealer about mid last year i had problems even on light rain getting CEL. one thing he did was the MAF is zip tied to something check if its still tied coz apparently once ur CAI moves a bit it pulls the wires causing it to throw a CEL. after that i never had problems. thats just my input though might be wrong. hope things will work well with urs

[Flagrum_3]

Here's a simple suggestion,...Stop idling your vehicle for 10-15 minutes! ...obviously its the cause of the check engine light and it is also not very good for your engine for many reasons, but burnt valves come to mind as one of the results of doing so.


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[mazda lover]

My 20year old truck lol sometimes does the same thing, but its stock no mods,
all I have to do is turn it off and restart, out she goes, no problem with emission test either.

[x_o_k_x]

Here's a simple suggestion,...Stop idling your vehicle for 10-15 minutes! ...obviously its the cause of the check engine light and it is also not very good for your engine for many reasons, but burnt valves come to mind as one of the results of doing so.


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never heard that idling for that long is bad for your car's engine..Only that it burns gas and illegal to do so. I have been idling for 10-15 min in the winter (not on mazda) and nothing happens.. And my friend left his car on for the whole night lol (dont ask!)

BTW Read this as it may help!
http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm

[Flagrum_3]

never heard that idling for that long is bad for your car's engine..Only that it burns gas and illegal to do so. I have been idling for 10-15 min in the winter (not on mazda) and nothing happens.. And my friend left his car on for the whole night lol (dont ask!)

BTW Read this as it may help!
http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm

I read your link and I'll just say it has nothing to do with backpressure, first time I ever heard that one!...It has to do with excessive heat, when you run your engine at idle your using mostly fuel with almost no air, this builds up excessive heat, especially on the valves and combustion chamber area.It used to be fine to do so before the advent of unleaded fuel, the lead in the fuel was there for reasons one being to cool things down when idling for long periods of time.But since they took the lead out it has been a known problem...Furthermore, it is not a thing that may occur from running the engine once or twice for long periods or cause damage to the valves immediately, but something that may happen over the long term, basically, shortening the life span of your engine dramatically.It is also why if you do have to sit idling for any length of time you would want to rev the engine periodically to introduce more air, which would help in cooling.

Also long periods of idling just helps in the unnessary build-up of carbon deposits and 'varnishing' of certain internal parts, ...another thing to avoid.

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