Problem fixed. It was the tune.

My CEL has been flashing rapidly when the boost start kicking in (not WOT, 1st thru 5th gear), especially when going up the hill. I can feel the engine still revving but the speedo and tach needle doesn't move at all. I have to let off the throttle, let the rev drop below boost for the CEL to stop flashing. Any idea? Physical problem or tune related?
The car has a base map, not fine tuned. Have regular bolt on like Intercooler and pipes, BR exhaust, K&N, boost controller set @ 25psi, Walbro 255.
I'm going to get my car dyno tuned next week and would like all the problem fixed so they can focus on the tune only.

 

That is usually set by your tuner to let you know when the car is seeing knock. I'd get your tuner to check out your tune and stay out of boost until then.

 

You most likely are getting more than 4-5 counts of knock which is not good. Have your tuner check it out. In the mean time make sure you don't have any boost leaks.

 

If your car has not been tuned to flash the engine light for knock count..the reason the engine light will flash is because your car is missfiring. I would Change your plugs and see if it goes away. Most tunes like fresh plugs before tuning anyway. The reason the engine light flashes during missfire is because you can ruin your cat when it is doing that.

N

 

I have never seen a CEL on any car flash because of a misfire. Where did you get this information from? I've also never heard of the reason for the light coming on is "because you can ruin your cat".

You do understand the difference between a misfire and knock right? Because a misfire won't ruin your cat, running too lean will.

 

This I'd dial the boost down until your tuner can look at it.

 

Thanks for all the help. I'll do a boost leak test and take it to my tuner asap.
What could be damage if this has been going on for awhile? I bought the car used with the base map and just now found the shop to dyno and finish it.
I bought the car in May, it only does this once in awhile. But I always let off the gas and take it easy to avoid the CEL flash.

 

I got this info from advanced engine diagnostics. OBD II cars will flash the MIL when misfire is detected, because raw fuel is not being combusted which will destroy the cat.

N

 

This may be true for some cars but not for the Evo. And, I've never heard of tuners setting an Evo up this way. Knock is always more important to tuners.

 

Here is some info on MIL flashing.

http://www.obdii.com/articles/OBDII_...s_Testing.html

Read under misfire detection.

And also..

http://www.villa-automotive.com/Reas...terFailure.htm

N

 

This is not something a tuner sets up. This is an OBD II protocol in misfire monitor. The reason for this is newer cars use 3 way cats which are very expensive to replace, and is there mainly to protect the consumer.

N

 

If you purchased your car used, it probably has the Tephra patch installed in the tune. It flashes the CEL when ever knock is detected. The car is feeling sluggish because the ECU is actually pulling timing, thus the loss of power. It's DEFINITELY a tune thing. A lot of times the maps are interpolating between the hi/low octane maps but one of the maps isn't jiving with your setup. Bottom line...see a tuner, they should be able to fix it no problem.

 

Good information but just not true for the Evo. If the SES flashes on an Evo, some tuner has set it up.

 

Not to high jack your thread but i got my car tuned not to long ago, and i only get knock very few times after the car has ran for a while (was told heat soak by the tuner) he said he couldnt get rid of it. Do you think changing my plugs out would help any? Maybe a step colder.

 

Audi's flash the Cel when the car misfires. I'm not saying it is that way on Evo's but it is another car the the Cel flashes when misfiring....