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Old 08-08-2005, 01:02 PM   #1
Hitokiri
Scooby Specialist
 
Member#: 2604
Join Date: Oct 2000
Chapter/Region: NESIC
Location: CA
Vehicle:
1999 2.5RSt
RBP

Default RS ECU wow - Knock Correction

So I was pretty sure that my shortblock was blown for about a week. I had just installed my Emanage Ultimate and the car was running extremely slugish and with almost no power. I had the boost way down till I had time to do some significant retuning and was hoping that it was just my learning curve and the new nature of the ultimate that was causing my issues.

Well I decided to log the stock ECU to see if everything was happy sensor wise and came accross an interesting MIL code "Knock Sensor Circuit Malfunction".

I had never seen that code but decided to check it out and swapped out the knock sensor... no luck

Looking at the dataloggs closer revealed that the ECU was droping to 4 degrees of advance at partial throttle!!!! 4! and holding at 4 seemingly indefinitely! If that is what limp mode entails thats pretty extreme!! I am pretty sure I wasn't in limp mode cause I could rev past 4k If I really tried. The car made absolutely no power at all with good reason!

SO I found that the Ultimate was pulling the knock sensor up! I haven't got the knock detection on the ultimate running yet but wired it regardless to see if it would work. So basically it was causing the stock ECU to see intense knock ALL the time.

After fixing the pull up issue the car now runs as smooth as ever again. Looks like I'll go back to using the J&S for knock detection till I find a better solution / get the ultimate detection compairible.

So the moral of the story is the Stock ECU is incredible in its capacity to remove timing with respect to knock. I see almost 40 degrees sometimes on light throttle and for it to drop it to 4! Thats pretty extreme!

On the other hand its good to know that the stock ecu has the capibility to trim ignition to that degree. I suggest everyone RSt buy a cable from http://tactrix.com/ and get the free ECU logger from http://www.tari.co.za/ and check out the iGN timing and knock correction that your ECU is currently running while turbo - send me the logs too just out of curiosity - hydraedit@gmail.com
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