What’s going on... second gear blower cutout
#1
What’s going on... second gear blower cutout
a bit about the build
2015 - c7 z51 manual
procharger p1sc tuned by reputable shop to 585hp
Car has about 6000 miles since the blower was added.
Symptoms:
Hard acceleration through 1st, shift to second and reduce throttle to about 25% the car will hesitate, a on-off-on-off-on stutter. Inside the car it’s very jerky at it does through this and occurs mid rpm range in second gear.
however, if I stay full throttle in same situation the car pulls aggressively with no stutter.
On one occasion, as I tried to diagnosis and see what was going on did several pulls changing throttle application. During last pull check engine light came on and stayed on. Scanner showed misfire cylinder. I had done several repeated pulls and a tire smoke.
What has been done:
Cleared codes
checked all spark plugs and gaps
changed blower and engine oil
Called tuner but I’ve move out of state, they said to check spark plugs.
I’m learning and this is my first blower car. I’ve checked all that I know but lost if this is normal. Have started to think maybe it’s tied to the blow off valve? Like it’s getting to much air and not enough fuel? If I stay full throttle through the gears it pulls the whole time with no hesitation. But if I go hard acceleration through first gear and back out of the throttle in second gear to about 25% it does the on-off-on-off hesitation. A classic scenario is pulling up to red light. Light flips green, accerlate hard and back out of the throttle in second gear 40-60mph, car hesitation to the point that the nose of the car is lifting, falling, lifting, falling.
Main issue is I look like I can’t drive my car. And once I cleared the original cylinder misfire it never came in again.
2015 - c7 z51 manual
procharger p1sc tuned by reputable shop to 585hp
Car has about 6000 miles since the blower was added.
Symptoms:
Hard acceleration through 1st, shift to second and reduce throttle to about 25% the car will hesitate, a on-off-on-off-on stutter. Inside the car it’s very jerky at it does through this and occurs mid rpm range in second gear.
however, if I stay full throttle in same situation the car pulls aggressively with no stutter.
On one occasion, as I tried to diagnosis and see what was going on did several pulls changing throttle application. During last pull check engine light came on and stayed on. Scanner showed misfire cylinder. I had done several repeated pulls and a tire smoke.
What has been done:
Cleared codes
checked all spark plugs and gaps
changed blower and engine oil
Called tuner but I’ve move out of state, they said to check spark plugs.
I’m learning and this is my first blower car. I’ve checked all that I know but lost if this is normal. Have started to think maybe it’s tied to the blow off valve? Like it’s getting to much air and not enough fuel? If I stay full throttle through the gears it pulls the whole time with no hesitation. But if I go hard acceleration through first gear and back out of the throttle in second gear to about 25% it does the on-off-on-off hesitation. A classic scenario is pulling up to red light. Light flips green, accerlate hard and back out of the throttle in second gear 40-60mph, car hesitation to the point that the nose of the car is lifting, falling, lifting, falling.
Main issue is I look like I can’t drive my car. And once I cleared the original cylinder misfire it never came in again.
#2
Bump. Could really use input from anyone. When I checked the spark plugs, one of the wire plugs removed effortlessly. Would a bad connection or bad wire lead to these symptoms??
#9
It was tuned via dyno and by reputable shop by the forum. I’ve called the tune shop but cross country so tough to swing by for diagnosis.
Whats weird is this issue seems to happen as the car builds up heat. I’m really starting to think maybe it’s a coil or wire based on the one instance of the misfire code coming in. But where that falls short in theory is on a hard pull it runs out no issue. It only happens when I back out of it in second gear
Whats weird is this issue seems to happen as the car builds up heat. I’m really starting to think maybe it’s a coil or wire based on the one instance of the misfire code coming in. But where that falls short in theory is on a hard pull it runs out no issue. It only happens when I back out of it in second gear
#10
My p1sc car has done this on 3rd only, twice after track days. In my case, both times, it was burnt wires. Change those and put heat sleeves on them. Try that.
I had cleaned the MAF, checked all intake piping, changed spark plugs (they were probably due soon), and none of that had fixed it.
Are you sure you're not getting a specific cylinder code?
My scenario was 3rd gear only, 4000+ rpm WOT, pretty much every time, misfires.
I had cleaned the MAF, checked all intake piping, changed spark plugs (they were probably due soon), and none of that had fixed it.
Are you sure you're not getting a specific cylinder code?
My scenario was 3rd gear only, 4000+ rpm WOT, pretty much every time, misfires.
Last edited by BrunoTheMellow; 10-10-2018 at 10:37 AM.
#11
Thank you for your response and experience. Yes it did have a specific misfire cylinder. But I was to quick to clear the code to see if it came in again that I didn’t note which cylinder. Pretty sure it was number 7 though which also is the spark plug wire that seems to be very easy to pop off the spark plug. Will experiment over the week to see if that’s the cause
#12
replaced cylinder 7 spark plug wire. took it for a test run. Seemed to run better but similar symptoms once the car got hot. Didn't seem as bad but was a quick test run. will report after more driving
#14
It’s not as simple as the blowoff valve fluttering between open and closed at part throttle is it?
i had the same setup as you with a very similar problem. If I started accelerating hard, changed gear and then had to let off the throttle, the car would surge. To me it felt like the bov was fluttering open and closed, causing the surges.
i fixed mine by upgrading to a 3.7” pulley and getting a retune from a reputable tuner. Not sure which fixed it, but one did.
i had the same setup as you with a very similar problem. If I started accelerating hard, changed gear and then had to let off the throttle, the car would surge. To me it felt like the bov was fluttering open and closed, causing the surges.
i fixed mine by upgrading to a 3.7” pulley and getting a retune from a reputable tuner. Not sure which fixed it, but one did.
#15
It’s not as simple as the blowoff valve fluttering between open and closed at part throttle is it?
i had the same setup as you with a very similar problem. If I started accelerating hard, changed gear and then had to let off the throttle, the car would surge. To me it felt like the bov was fluttering open and closed, causing the surges.
i fixed mine by upgrading to a 3.7” pulley and getting a retune from a reputable tuner. Not sure which fixed it, but one did.
i had the same setup as you with a very similar problem. If I started accelerating hard, changed gear and then had to let off the throttle, the car would surge. To me it felt like the bov was fluttering open and closed, causing the surges.
i fixed mine by upgrading to a 3.7” pulley and getting a retune from a reputable tuner. Not sure which fixed it, but one did.
#16
Also the off off the shelf procharger kit has a fairly quiet bov.
Last edited by jimxms; 10-15-2018 at 04:58 PM.