flickering DTC???

[Beanokid69]

I have a problem when I run my car hard my CEL will start to flicker depending what rpms im cruising at afterwards, or it will stay on, flicker alittle bit and only go off when I give it throttle. I dont know whats causing this and im not getting an error code due to it going off and on. Im running DSMlink.

What could this be?

 

[Novablue454]

A blinking MIL (check engine light) means you are having a what is called a Type A misfire. Your likely destroying your cat, and possibly the turbo. Can someone confirm? Check all plugs and wires. Hope this helps.

 

[Beanokid69]

well i believe my plugs to be fouled and I have a COP so could it be the bad plugs?

 

[tqmx1]

Have the caps been changed in the ECU. They can give all sorts of fits when they start to go bad. You can chase your tail from one end of the engine bay to the other for $5.00 worth of parts.

 

[Beanokid69]

well when i sent my ecu into dsmlink to get it installed they rebuilt it

 

[tqmx1]

Scratch that idea then.

 

[Novablue454]

yes, it could very well be bad plugs. Bacially whats happening is that the ECU is seeing a fluctuation in crankshaft speed on a certian cylinder in the firing order. So instead of combustion taking place in the cylinder, the fuel is making its way to the exhaust, where the exteme heat is combusting it.

 

[Beanokid69]

i changed the plugs today and even when i didnt push the car hard it started to flicker like normal and seemed to idle roughly after that.

 

[Novablue454]

what type of plugs and what did you gap them at?

 

[Boo5t_Addict]

Manufacturers designed the blinking CEL to signal that you should immediately turn the car off. In an automotive diagnostics class that I took, it was explained that the ecu sees a misfire in a cylinder, and just dumps massive amounts of fuel into that cylinder in the hopes that it will all ignite and combustion will start back up normally again. This doesn't work however, because too much fuel continues the misfire, and the ecu sees this and triggers the CEL to blink. Seriously, don't drive your car when it does this, the whole situation has a great potential to break a lot of parts. Your cat will melt, you can possibly have the igniting fuel in the exhaust misfire back into the engine, all sorts of things can happen. I remember asking my instructor if it was ok to limp it home and just go to a shop the next day if I was ever caught in a situation like this, and he said that if somethign like that ever happened you should shut the car off immediately. Usually a misfire is caused by something simple, but if left unchecked, can cause a lot of stuff to break down (like melting your cat, as previously stated).

 

[Beanokid69]

what would cause this...and its not a steady blinking or anything like that its like if you were to have to wires that are bearly circuiting which would make the light flicker...its an unconsistant very quick flicker, like a loose bulb would flicker.

 

[Novablue454]

oh. Well i personally have never seen the misfire blink, but ive always heard thats a solid, steady, blinking. So im not sure. When its happening is the timing changing at all?

 

[Talesin]

You realize that DSMLink can be configured to blink the CEL as a 'knock light', right?

Knock MIL- Flashes the check engine light if timing is pulled back more than 5 degrees (user definable) due to knock.

That'd be my guess.

If it's an actual DTC, our ECUs will store it until reset (battery disconnected for 30s-2m) and you can pull it out with a logger, or the Link software. Not just only while it's occurring, even for DTC conditions that allow the CEL to turn off again after they're done. So if you ever get a misfire code, it'll be waiting in the DTC list when you get home.

 

[Beanokid69]

I know that, I set the DTC light to knock already but I also know when my car will knock and phantom knock, and it doesnt do it at 3500rpms cruising

 

[Novablue454]

or pehaps it didnt used to knock under that condition. Maybe you got a bad tank of gas thats causing a knock? Or your knock sensor could be going?

 

[Beanokid69]

ok, well just wait for the log next time it does it. Ill post it asap, thanks.