mrmint69
03-18-2008, 06:19 AM
I had 5 wot runs i recorded. I got knock on 3 of them and the 2 that didn't had the O2's reading in the 946-968 range the whole time. When i got knock the O2's read 884-915. I checked the fuel pressure and it is at 48 during the entire wot run. What are the normal reading for wot on supercharged engines? What could be causing this problem?
FireChicken1995
03-18-2008, 06:08 PM
maby just timing? back off timing a degree or two and see how that does
mrmint69
03-19-2008, 03:39 PM
The tune was done for the new injectors and the supercharger. If the old setup with the stock injectors and the fmu worked with no knock it must be something to do with the new changes just made. If the car is running lean i assume this could cause the knock i see but it appears that only a wideband will show this. How would you guys suggest i go about fixing this? I have had suggestions of backing off the timing but that would just be bandaging the problem and not fixing whats happening. I have a MSD 6btm so i can go up to 18 degrees.
97s10ondubs
03-30-2008, 09:27 AM
The tune was done for the new injectors and the supercharger. If the old setup with the stock injectors and the fmu worked with no knock it must be something to do with the new changes just made. If the car is running lean i assume this could cause the knock i see but it appears that only a wideband will show this. How would you guys suggest i go about fixing this? I have had suggestions of backing off the timing but that would just be bandaging the problem and not fixing whats happening. I have a MSD 6btm so i can go up to 18 degrees.
Your old tune may have had the knock sensor desensitized. Backing off the timing would not be bandaiding, it's fixing the cause. Too much timing and not enough octane will cause knock, so fix either one of those. Put in race gas, or lower the timing.