captdistraction
GrumpyRacer
The setup:
2011 chassis racecar, new custom coyote build with about 8 hours of runtime on it.
stock fuel tanks, radium surge tank with regulator (feed connected to stock tank pump outlet, radium regulated output connected to stock hardline to rail, overflow connected to tank at filler neck connection)
AEM 50-1200 E85 pump in radium tank
Stock PCM with aftermarket tune via SCT flasher, all new harnesses, updated style VCT solenoids; cobrajet intake and monoblade throttlebody
3 year old PC680 Battery charged via boss 302 alternator kit with regulator plugged in (stock configuration driven by PCM) - kept on tender when not in use
The issue:
over time in a race, the car will bog down coming out of a corner (it seems like its mostly right hand turns), and this has gone from a light stutter, to a full second of weirdness, to a complete inability to rev/lay down power where I had to be towed in from a race. This has shown up in the last few events (first time I barely noticed it and figured I was low on fuel). The next event was sound restricted and I found the car getting worse over time, and the last race on the 5th lap (with 2 laps under caution) the car cut out coming out of a right, I also could not restart the car:
see the issue starting at the 7 minute mark - along with running data visualization.
I do measure fuel pressure, albeit at the output of the radium surge tank and not at the rail (which means I might not see a pinched line or other feed issue - as it would just dump extra pressure through the regulator on the tank).
Fuel pressure is consistent, however, as is voltage (as we considered an internal battery short that might show up under heavy G's along with why its so difficult to restart the car)
I checked grounds, wiring connections, inspected the crank trigger sensor (it was clean), completed a neutral profile reset service, and then bypassed the surge tank. I ran the next day without issue, however, I did have one little blip in practice but its hard to tell if that was related or not. Data showed nothing real interesting.
data from the fault can be seen here: https://podium.live/events/nasa-az-st2-chuckwalla-valley-raceway-2-13/device/50mustang?laps[]=4 - there's a selection for graph by time to see the data once the car came to a rest.
Here's some screen grabs of the relevant sections:
Thoughts on what this could be? Could I have missed a wrench light and limp mode? Because I don't have a PCM keepalive, I don't believe I had any saved errors/CELs to review (I need to remember in these cases to leave the car on if I can to ensure recording). My data is also limited to performance focused data, not so much engine parameters like spark advance, cam timing, etc. I can pick up something like an AIM solo DL to start monitoring operational parameters and see if that data sheds any light, but I'm baffled. The car runs now, but I don't like the idea of not knowing why this was occuring or not using the surge tank; also the risk of losing a race session due to this issue is unfortunate.
All I have for moving forward steps are:
-collect more data
-check surge tank pump (the surge tank was full of fuel upon disassembly)
-continue tracing lines, wires, grounds
2011 chassis racecar, new custom coyote build with about 8 hours of runtime on it.
stock fuel tanks, radium surge tank with regulator (feed connected to stock tank pump outlet, radium regulated output connected to stock hardline to rail, overflow connected to tank at filler neck connection)
AEM 50-1200 E85 pump in radium tank
Stock PCM with aftermarket tune via SCT flasher, all new harnesses, updated style VCT solenoids; cobrajet intake and monoblade throttlebody
3 year old PC680 Battery charged via boss 302 alternator kit with regulator plugged in (stock configuration driven by PCM) - kept on tender when not in use
The issue:
over time in a race, the car will bog down coming out of a corner (it seems like its mostly right hand turns), and this has gone from a light stutter, to a full second of weirdness, to a complete inability to rev/lay down power where I had to be towed in from a race. This has shown up in the last few events (first time I barely noticed it and figured I was low on fuel). The next event was sound restricted and I found the car getting worse over time, and the last race on the 5th lap (with 2 laps under caution) the car cut out coming out of a right, I also could not restart the car:
I do measure fuel pressure, albeit at the output of the radium surge tank and not at the rail (which means I might not see a pinched line or other feed issue - as it would just dump extra pressure through the regulator on the tank).
Fuel pressure is consistent, however, as is voltage (as we considered an internal battery short that might show up under heavy G's along with why its so difficult to restart the car)
I checked grounds, wiring connections, inspected the crank trigger sensor (it was clean), completed a neutral profile reset service, and then bypassed the surge tank. I ran the next day without issue, however, I did have one little blip in practice but its hard to tell if that was related or not. Data showed nothing real interesting.
data from the fault can be seen here: https://podium.live/events/nasa-az-st2-chuckwalla-valley-raceway-2-13/device/50mustang?laps[]=4 - there's a selection for graph by time to see the data once the car came to a rest.
Here's some screen grabs of the relevant sections:
Thoughts on what this could be? Could I have missed a wrench light and limp mode? Because I don't have a PCM keepalive, I don't believe I had any saved errors/CELs to review (I need to remember in these cases to leave the car on if I can to ensure recording). My data is also limited to performance focused data, not so much engine parameters like spark advance, cam timing, etc. I can pick up something like an AIM solo DL to start monitoring operational parameters and see if that data sheds any light, but I'm baffled. The car runs now, but I don't like the idea of not knowing why this was occuring or not using the surge tank; also the risk of losing a race session due to this issue is unfortunate.
All I have for moving forward steps are:
-collect more data
-check surge tank pump (the surge tank was full of fuel upon disassembly)
-continue tracing lines, wires, grounds