EfiniX
Well-known member
So my car has been running terrific since moving it to SD a few months ago. I did bring the boost down a touch from 24psi to 22 to work some intermittent knock out of the system. Lots of fun!
Last week, I was pulling onto the freeway and had to push past a BMW. I got on the pedal a bit in 3rd gear and while I did pass him, the car felt a bit grumbly. So later in the day I did a WOT pull in 3rd and saw a ton of knock. Didn't have a logger on, but based on the dash, I hit 3 lights on the stock boost gauge. It's what, 7 counts per light, so that's a decent amount. I thought I might have some poopy gas, but it did the same thing on the next tank (just yesterday). 92oct from Chevron is usually fine, so I started considering other factors.
First, I checked my knock sensor threshold. It was set to 4500RPM's (which is right above my boost threshold on my big T3/04) and 70% throttle. That throttle value seems a bit high. Got me wondering if that grumble I was feeling was actually knock that my car wasn't detecting. I doubt I was more then 60% on the throttle when I felt it passing that BMW. (sorry car!). those of you with link and lumpy cams. What's your knock threshold set at?
For now, I'm going to replace the BPR7ES plugs that are installed with some BR7ES plugs. I actually had BR7's on for a while to deal with some spark blowout issues, but when I switched to speed density, I had the OmniBar sensor fail almost immediately, telling the engine it was getting a million pounds of boost and stalling the car on the freeway by going super rich. Got that sorted out, but English pulled my BR7's and installed BPR7's since that's what they had in the shop handy.
I figure I'll also do the plug wires since the ones that are installed, while NGK, are 7 years old. If that doesn't work, then I'll start searching for boost leaks.
Log coming tomorrow morning. For now, any thoughts?
(bonus question: can spark blowout cause knock?)
You guys are the best!
Last week, I was pulling onto the freeway and had to push past a BMW. I got on the pedal a bit in 3rd gear and while I did pass him, the car felt a bit grumbly. So later in the day I did a WOT pull in 3rd and saw a ton of knock. Didn't have a logger on, but based on the dash, I hit 3 lights on the stock boost gauge. It's what, 7 counts per light, so that's a decent amount. I thought I might have some poopy gas, but it did the same thing on the next tank (just yesterday). 92oct from Chevron is usually fine, so I started considering other factors.
First, I checked my knock sensor threshold. It was set to 4500RPM's (which is right above my boost threshold on my big T3/04) and 70% throttle. That throttle value seems a bit high. Got me wondering if that grumble I was feeling was actually knock that my car wasn't detecting. I doubt I was more then 60% on the throttle when I felt it passing that BMW. (sorry car!). those of you with link and lumpy cams. What's your knock threshold set at?
For now, I'm going to replace the BPR7ES plugs that are installed with some BR7ES plugs. I actually had BR7's on for a while to deal with some spark blowout issues, but when I switched to speed density, I had the OmniBar sensor fail almost immediately, telling the engine it was getting a million pounds of boost and stalling the car on the freeway by going super rich. Got that sorted out, but English pulled my BR7's and installed BPR7's since that's what they had in the shop handy.
I figure I'll also do the plug wires since the ones that are installed, while NGK, are 7 years old. If that doesn't work, then I'll start searching for boost leaks.
Log coming tomorrow morning. For now, any thoughts?
(bonus question: can spark blowout cause knock?)
You guys are the best!