TexasBlownV8
Formerly TexasBlownV6
On my KB 2.6, 18 psi, GT500 pumps, I have an issue that recently developed.
Driving around part throttle, staying out of boost, car runs fine, at all rpms and speeds. When I go into boost, whether part-throttle or wot, the car spits and sputters and acts like it is missing out or not getting fuel. This happens at any RPM where I get into it, typically in the 2000-3500 range.
I drained the fuel and changed the filter a while back to resolve this, no help, as initially i thought it might be some bad gas that I bought. That was 2 half-tanks ago that I did this.
The BPV is working properly, opening and closing as expected.
The issue seems to manifest itself when the GT500 pumps kick into boost-mode (dual BAP power increases to them; I monitor that via a couple of LEDs), and the fuel pressure jumps up into the mid to upper 40 psi range on my gauge. Boost tries to get up only gets to about 3-6 psi while this is going on.
When I get into less boost, just barely below the threshold where the GT500 BAP kicks on, the issue does not occur. I can build a little boost and hold it just fine (but what's the fun in that!).
Strange thing, this will sometimes not happen at all, and the car will go into boost and run like a bat out of hell, but I think only when not fully warmed up. Although, most times when trying to get into it, it happens.
Coolant temps and IATs are normally.
AFR appears to stay what it was before going into boost (although I dont stay into it long to see it change). I would expect it to go rich if there was any misfiring, but it isn't.
I checked the air intake and it looks normal and correct.
The COPs have upgraded wires running to them (no boost-a-spark). Have had no previous issues with spark blowout.
The car ran flawlessly last October while being dyno tuned by Lito and for a couple months after that. I tried an older (not one I'd use any more) tune, and it does the same thing. I'm confident this is not a tuning issue, but something else is going on.
No DTCs get thrown.
Next I'm thinking of checking the spark plugs, see what they look like; they are not that old, were replaced maybe 1000 miles ago, last year. Maybe try a previous set, see if it is a spark plug issue.
And if still occurring after that, I'll do some datalogging.
Maybe a fuel injector issue, since the AFR is not radically changing? Although, I can't really go full WOT, it'll just sputter and barely stay running.
Any useful suggestions?
Driving around part throttle, staying out of boost, car runs fine, at all rpms and speeds. When I go into boost, whether part-throttle or wot, the car spits and sputters and acts like it is missing out or not getting fuel. This happens at any RPM where I get into it, typically in the 2000-3500 range.
I drained the fuel and changed the filter a while back to resolve this, no help, as initially i thought it might be some bad gas that I bought. That was 2 half-tanks ago that I did this.
The BPV is working properly, opening and closing as expected.
The issue seems to manifest itself when the GT500 pumps kick into boost-mode (dual BAP power increases to them; I monitor that via a couple of LEDs), and the fuel pressure jumps up into the mid to upper 40 psi range on my gauge. Boost tries to get up only gets to about 3-6 psi while this is going on.
When I get into less boost, just barely below the threshold where the GT500 BAP kicks on, the issue does not occur. I can build a little boost and hold it just fine (but what's the fun in that!).
Strange thing, this will sometimes not happen at all, and the car will go into boost and run like a bat out of hell, but I think only when not fully warmed up. Although, most times when trying to get into it, it happens.
Coolant temps and IATs are normally.
AFR appears to stay what it was before going into boost (although I dont stay into it long to see it change). I would expect it to go rich if there was any misfiring, but it isn't.
I checked the air intake and it looks normal and correct.
The COPs have upgraded wires running to them (no boost-a-spark). Have had no previous issues with spark blowout.
The car ran flawlessly last October while being dyno tuned by Lito and for a couple months after that. I tried an older (not one I'd use any more) tune, and it does the same thing. I'm confident this is not a tuning issue, but something else is going on.
No DTCs get thrown.
Next I'm thinking of checking the spark plugs, see what they look like; they are not that old, were replaced maybe 1000 miles ago, last year. Maybe try a previous set, see if it is a spark plug issue.
And if still occurring after that, I'll do some datalogging.
Maybe a fuel injector issue, since the AFR is not radically changing? Although, I can't really go full WOT, it'll just sputter and barely stay running.
Any useful suggestions?
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