problem with ETC/TAC and individual throttle body manifold
05-30-2005, 07:27 AM
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problem with ETC/TAC and individual throttle body manifold Hi,
I installed the Harrop Hurricane manifold on my C5 corvette.
The stock throttle motor is bolted to a gear on the new manifold. The TPS sensor is bolted to the first throttle blade.
Turning on the ignition, I get the following codes:
P1120 Throttle Position (TP) Sensor 1 Circuit EPA Pending ($10) Powertrain Control Module (PCM)
P1220 Throttle Position (TP) Sensor 2 Circuit EPA Pending ($10) Powertrain Control Module (PCM)
P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance EPA Pending ($10) Powertrain Control Module (PCM)
Starting the engine with the codes present, there is no reaction to pushing the accelerator. Sometimes the engine dies right away, sometimes it barely runs. On deleting the codes, the trottle blades open all the way, and the rpms shoot up immediately.
With a Tech II, we could open and close the throttle blades. Give it 20%, the blades open 20 degrees, give it 40% and the throttle blades open further. At 90%, the throttle blades are opened 90 degrees, the codes pop up again, and the throttle blades close immediately. The throttle blades can not open more than 90 degrees, and it seems TPS percentage is 90 at that point. With the stock throttle body, it looks like it opens more than 90 degrees, maybe 10 degrees more.
Since the throttle blades can be moved with the Tech II, and the TPS shows at least reasonable numbers, I think the electronics are okay. Of course there is a chance a wire broke, or the TAC module died, but I don't really see a reason for that.
It looks like the TPS and TAC motor lost their calibration. Is there a way to initiate a recalibration?
Any other ideas what is going on, or how this could be fixed?
One more thing I think of now is hooking up the original throttle body again, and see if it works with that one. Maybe this had nothing to do with the manifold, and for some reason the sensor broke or the TAC module died.
Any input welcome. Thanks, Till
I installed the Harrop Hurricane manifold on my C5 corvette.
The stock throttle motor is bolted to a gear on the new manifold. The TPS sensor is bolted to the first throttle blade.
Turning on the ignition, I get the following codes:
P1120 Throttle Position (TP) Sensor 1 Circuit EPA Pending ($10) Powertrain Control Module (PCM)
P1220 Throttle Position (TP) Sensor 2 Circuit EPA Pending ($10) Powertrain Control Module (PCM)
P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance EPA Pending ($10) Powertrain Control Module (PCM)
Starting the engine with the codes present, there is no reaction to pushing the accelerator. Sometimes the engine dies right away, sometimes it barely runs. On deleting the codes, the trottle blades open all the way, and the rpms shoot up immediately.
With a Tech II, we could open and close the throttle blades. Give it 20%, the blades open 20 degrees, give it 40% and the throttle blades open further. At 90%, the throttle blades are opened 90 degrees, the codes pop up again, and the throttle blades close immediately. The throttle blades can not open more than 90 degrees, and it seems TPS percentage is 90 at that point. With the stock throttle body, it looks like it opens more than 90 degrees, maybe 10 degrees more.
Since the throttle blades can be moved with the Tech II, and the TPS shows at least reasonable numbers, I think the electronics are okay. Of course there is a chance a wire broke, or the TAC module died, but I don't really see a reason for that.
It looks like the TPS and TAC motor lost their calibration. Is there a way to initiate a recalibration?
Any other ideas what is going on, or how this could be fixed?
One more thing I think of now is hooking up the original throttle body again, and see if it works with that one. Maybe this had nothing to do with the manifold, and for some reason the sensor broke or the TAC module died.
Any input welcome. Thanks, Till
05-30-2005, 02:43 PM
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I found the problem. The TPS voltage with the throttle closed is 0.1V. If this voltage is lower than 0.13V, the codes come up.
Tomorrow we will turn turn the TPS sensor a little bit, to get a base voltage above 0.13V.
Till
Tomorrow we will turn turn the TPS sensor a little bit, to get a base voltage above 0.13V.
Till
