stony Posted July 20, 2002 Share Posted July 20, 2002 Ok this is starting to get aggravating!!!! MY timing is set like this. idle 20 degrees. it steadily advance to 37 degrees till 3500-redline. retard pulls it back all the way to 22 degrees at full booste and im still hearing Knock (i think) when i shift from 1st to 2nd and get on it. then again in top of third. the car does not buck or fall on its face in fact all it does is make the noise. i can richen it up lean it out, play with timeing and it never changes its allways in the same area. what im starting to think is one or both turbos are stating to go bad and make this noise im hearing when they are under a load. does this sound like a possibility? im lost.... gonna take it to a dyno and run it with af ratio and knock meters hooked up and see what i have but we will see. any suggestions before the dyno? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 20, 2002 Share Posted July 20, 2002 Stony, are you using a knock sensor and are you allowing the ECM to pull out timing when it gets the knock signal? This is a battle I have been fighting for a long time and have concluded it is false knock, meaning the knock sensor is sensing something but it is not the result of a lean condition. It is either something touching or just bad harmonics. Luckily, with the chip I am using I can tell it to ignore knock up to 40mph. I amn ot concerned because true knock is less damaging in 1st gear and for me (you also) 40mph is only about 1-sec. Do not rely on your ears to detect knock! It is possible that the knock in 1st and the knock in 3rd are not related and the concern should be the knock in 3rd being a lean condition or too much timing, but 22* total is not high unless you are running low-octane with pump gas or old race gas. Look for anything that could be touching and if you suspect the turbos, only way to know is to pull them off and remove the housings to look for scratches inside. Quote Link to comment Share on other sites More sharing options...
stony Posted July 20, 2002 Author Share Posted July 20, 2002 dual knock sensors not hooked up I know its stupid just thought i try to get it tuned by ear which up to this point i was successfull. I was thinking the exact same thing about the turbos. IM going to try taking it down to 20 degrees and see what happens. Now that i think about it the one thing that did make a difference in the noise was turning up the booste. My summit AF ratio gage says im rich and my plugs confirm that but the higher the booste the louder the noise is and it also happens sooner like in first and all the way thru 2nd and it also seems to be louder. If it was detonation that loud, wouldnt it be stumbling and falling on it nose or something. the only time it falls off on power or stumbles is when it really rich and i have a black trail of smoke but anyways ill try looking at the turbos and see whats up. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 21, 2002 Share Posted July 21, 2002 You need data logging of th esignal coming from the knock sensors. Even if it's just a tape recorder using them as a microphone! On my Supra I can see knock sensor voltage in the .07 range and then suddenly see it spike to .3volts. THAT is knock and usually I cannot hear it by ear. A hundred RPM later the engine is back to .07 volts again. A/F when this occurs can be as rich as 11:1! The AEM tech said that they have a better time burying knock with fuel than they do spark retard on the Supra BTW - not sure if that applies to you. Anyway, if you can datalog that bad boy somehow you'll know exactly what's going on. Hell, I'm swimming in data with my ECU, it's freakin' awesome! Stupid question - is th eRB motor a 6 or a 4cylinder motor? Quote Link to comment Share on other sites More sharing options...
stony Posted July 21, 2002 Author Share Posted July 21, 2002 2.6 L DOHC twin turbo I agree i need something. i was looking at MOTEC ADL anyone know the price on this baby looks expensive I think some time this week im going to go to the dyno and tune it there Quote Link to comment Share on other sites More sharing options...
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