Clamped the map sensor with a diode, cars acting weird..
07-02-2004, 04:53 PM
#1
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Clamped the map sensor with a diode, cars acting weird..
The engine chokes as if the TB is opening and closing rapidly. The boost is slow, and is lower than normal. I think its the TB because its like the ecu is trying to open the TB as least as possible, which would cause boost to be lower than normal. Also I'm getting a bit of DV fluttering when i let off the throttle..
The car idles fine, i checked the map voltage at idle, and its around 1.85v. The thing is, everytime i splice something into the map wiring such as a volt meter the ecu puts out a map signal too low code"
I believe Audi2ptzero is the only person thats installed a diode clamp..
The car idles fine, i checked the map voltage at idle, and its around 1.85v. The thing is, everytime i splice something into the map wiring such as a volt meter the ecu puts out a map signal too low code"
I believe Audi2ptzero is the only person thats installed a diode clamp..
07-02-2004, 05:31 PM
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no resistor, zener 3.3v 1w diode.. more
cathode band faces the signal wire which is blue gray, and the other end goes to the ground/black wire.. no resistor, the transverse 1.8t guys saying nothing about installing a resistor..
07-02-2004, 06:01 PM
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Is the chip your running set for just a 3.3 volt reading?
I have a resistor on the signal line just before my zener 4.7 volt diode. I run this 4.7 because my chip was tuned for 20-21psi and this keeps the ecu very happy.
07-02-2004, 06:03 PM
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i'm running this diode on the stock chip to prevent limp mode.
I know its 3.3v because I spliced a volt meter before to check what voltage i would need for before limp which was just before 1bar..
07-03-2004, 04:15 AM
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3.3v is WAY too low...
If you car uses the same boost sensor as the B5 S4. On my car, a 4.7v diode clamps at ~1 bar (2040 mbar absolute) and 3.9v diode clamps at ~0.6 bar (1640 mbar absolute).
I'm guessing the 3.3v diode is clamping your sensor to below atmospheric pressure and the car doesn't know what to do about it.
-Dave Pramanik
I'm guessing the 3.3v diode is clamping your sensor to below atmospheric pressure and the car doesn't know what to do about it.
-Dave Pramanik
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07-03-2004, 05:53 PM
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Car's cold start was rough today, CEL came on, and smelled really bad/ rich..
So i just took out the diode.. i have a 4.3v i was going to use.. so i guess i could try that. but like i said, even when i splice in a voltmeter, the boost is affected.. So it seems like an install error?
07-04-2004, 04:59 AM
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Really? I didn't realize that the B5 A4 and B5 S4 used different MAP sensors.
I think trying to do that on the stock chip is not such a good idea. I know with the S4, the stock chip runs much leaner than aftermarket chips. At higher boost levels, that is asking for trouble.
-Dave Pramanik
-Dave Pramanik