random knock started last night???

[dt23400]

So last night i was driving back from south bend to my girlfriends house. just filled up and wasnt beating on it what so ever. Stomach was too full haha. So i get about a mile away and i get into it a lil bit in second gear and just got blinded by the knock likght in my car and it stumbled a litll bit but has been getting better and now only happens under full throttle at about 5500 rpms and up. this is the first time ive ever seen it knock. So what i want to know is there anyway to narrow things down to find out whats going on. I have a data logger on the way. Should be in next week sometime i hope. But any extra info would help. Thanks guys

 

[1993tsigrayawd]

Feel your knock sensor for any goo. If not then bust out the logger and see if its too lean or too rich.

 

[dt23400]

yea i checked that last night after i jumped on here looking for ideas and its there pretty good cant feel any metal or anything and i just ordered the logger off line today from 1glink.com price seemed ok for what it is so yea

 

[dt23400]

Could to hi of an oil level cause it also cause it sometimes knocks supposably and sometimes doesnt. I dont actually here it knocking and no im runing a mix of93 with a little bit of e85. COuld the cold weather change here have an effecti with my tune from the tune that i had from when it was warmer outside.

 

[95blackGsTurbo]

What are you using to tune and monitor A/F's with? Remember you need to add about 30% fuel when running E85 so if your mixture is off then you could be running very lean and causing the car to knock. Colder temps can cause the tune to be a little off due to the density of the air changing. It will cause the car to lean out, which brings me back to my first question.

 

[dt23400]

well i jsut got my logger yesterday and i started playing with it. I still have to learn what to watch but the only thing i see about fuel on that looger is the fuel trims. So far my low is 118% and mid and hi are still on 100%. My knock only gets to about 3 sometimes at wide open throttle. I seem to have the most knock right after i get off throttle. I had a max of 43 when just crusing. I dont hear or feel the car knock tho. mmcd is the program i am using. Im trying to get palmnstein set up but i cant get it to log. I have a fuel ratio gauge but i havent gotten it in yet and wondering if i should bother cause there not all that accurate or have i been mislead by others??

 

[BigBeans]

Quality widebands are accurate to .1, if you have one, install it.

A narrow band is basically useless.

Temp can have a lot to do with it. Air density causes the car to run leaner, and sometimes causes a little more boost.

Going from 60 degrees to 40 degrees, my car went from 0.4 counts of knock to 2 counts, so it can make a significant difference if your tune is aggressive.

Also, the composition of e85 changes seasonally. It can vary significantly, from 60-90% ethanol. I think they use less ethanol and more gasoline in the winter, so this would make your car more prone to knock also.