Knock

[TSIanger]

Hey guys, I am new to the forum, but not new to DSMs. I have a 91 Talon Tsi FWD, with a ton of miles (166k). The engine bay had a $3000 face lift about 12K miles ago, so I am not overly worried. I am not running much boost, 13lbs I believe, and everything is stock. The problem is, I went to atmospheric with the blow off valve. I knew all the potential problems before I did this, but it wasn't done for performance. I have all the typical DSM problems, surging idle, cracked exhaust manifold. blah blah blah. The real problem I want to inquire about is, when the BOV fires, it emits the most awful smell in the entire world. I am 90% I have a major fuel problem, but I am no mechanic. I also did a quick datalogger search, and I have 42 counts of knock. I am pretty sure that's a crapload, and near detonation. The O2's were near perfect though, I need help!!! THANKS

 

[boostedinaz]

You need to first fix as many little things as you can so that it is narrowed down to just a few problems. If you have alot of them they all could contribute to you knock count. On my FWD car it was a bad O2 sensor that caused me to get knock like that. I am also venting becasuse I was a dumbshit when I started with that car. I replaced the O2 and it ran great for a bit. I am now returning it to stock for a DD. The logger said my O2 were rich under full throttle but the O2 was the problem so it was reading incorrectly. This is one of the common problems with venting.

Michael

 

[TSIanger]

Thanks for the insight. I just replaced my O2 maybe a month ago, so I hope that isn't the problem. If I remember the reading correctly, I think my O2 was also a little rich under full throttle. I've been using it as a daily driver for about a year and half, and was just about to consider doing light modifications. Being as the head was recently rebuilt, I thought it could handle a little squeezing of HP, but now I am not so sure. I am most likely getting a new one (90 TSI AWD w/ mods) this weekend, but I still want to keep the 91 running well. Any more info is greatly appreciated.

 

[Mac3KGT]

TTT help this guy out I datalogged his car for him and saw it myself. I believe what we are seeing is phantom knock. At 1200 RPM(a quick tap of the pedal) we saw 20 counts. Im not exactly a DSM guy(I have a 3000gt VR-4) but i know that 20 counts after a SLIGHT rev is insane. The car is also very loud as the rpm's increase, more than likely due to the cracked manifold.(we dont know for sure that it is) And yes when the car blows off it smells SO bad almost like sulfer, you can barely breathe! The o2 voltage had a max reading of 1.17v if that helps. I believe that the problem lies somewhere in the fuel system. Anyone??

Mac