LT1 falling on its face
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TECH Fanatic
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Joined: Oct 2007
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From: Central Valley, CA
LT1 falling on its face just installed BBk shorty headers, magnaflow catback, and replaced plugs and wires. Car has lots of low end torque and picks up rpm really well but now the car seems to fall on its face after every shift (a4) unless I am at WOT.
Launching!
Joined: Sep 2007
Posts: 245
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From: Clover, South Carolina
My first thought is the knock sensors picking up false knock at the shift. With the modifications you put on, perhaps something is hitting/vibrating somewhere when the tranny shifts?
Do you have access to a scan tool to monitor what the computer is seeing at each shift?
Do you have access to a scan tool to monitor what the computer is seeing at each shift?
Thread Starter
TECH Fanatic
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Joined: Oct 2007
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From: Central Valley, CA
as for the timing adjust, that doesn't even deserve a response (yeah I advanced my distributor 12 degrees and still nothing lol) I made sure to gap all of my plugs (NGK G-Power Platinum) @0.50 which is what my emissions sticker called for. And as for the knock sensors I am not sure if it could be getting some sort of vibration but I reused my factory Y and had everything welded solid and am utilizing all of the factory hangers so i don't know what it could be picking up but no I do not own a scan tool but if it comes down to it I will purchase one. I am not exactly sure what the knock sensor is designed to do and why it would make the engine stumble at low to mid rpmf that indeed is the problem.
It is pretty easy to test your knock sensor, also if it is malfunctioning it will throw a code.
Easy way to test, unplug the wire going to it, get your multimeter out and put one lead on the knock sensor pin and the other lead on a chassis ground. Set your multimeter to AC VOLTAGE AC VOLTAGE AC VOLTAGE, and beat around on the motor (oil pan, etc) with your hand. If it shows AC voltage spikes, your knock sensor is working.
I am not sure how much a y-pipe can set off a knock sensor.. my y pipe is rubbing the floor a little so I am wondering about this myself. Need to move it tomorrow.
Easy way to test, unplug the wire going to it, get your multimeter out and put one lead on the knock sensor pin and the other lead on a chassis ground. Set your multimeter to AC VOLTAGE AC VOLTAGE AC VOLTAGE, and beat around on the motor (oil pan, etc) with your hand. If it shows AC voltage spikes, your knock sensor is working.
I am not sure how much a y-pipe can set off a knock sensor.. my y pipe is rubbing the floor a little so I am wondering about this myself. Need to move it tomorrow.
Launching!
Joined: Sep 2007
Posts: 245
Likes: 1
From: Clover, South Carolina
Wait, I think I missed the part where you said WOT this problem doesn't present itself. Still could be what I originally suggested, but now my first thought is different.
Check your plug wires.
Check your plug wires.
