LT1-LT4 Modifications 1993-97 Gen II Small Block V8

LT1 Knock Sensor

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Old Dec 19, 2007 | 01:57 AM
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Default LT1 Knock Sensor

I figured out that the code setting in my 95 A4 is due to the wrong (OBDII) knock sensor. I haven't had a chance to change it just yet and I'm wondering...what is going on when the knock sensor code is set? Is max timing retard being set? How much of a difference in power can I expect?
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Old Dec 19, 2007 | 02:05 AM
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Yes it's essentially the max amount all the time. You will lose a great deal of power and it will run poorly.

The knock sensor is cheap, like $25 max. Just swap it out.
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Old Dec 19, 2007 | 02:08 AM
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Wow...

I bought the car with a broken transmission. The previous owner put every bolt-on item he could think of and some random cam. It broke the stock transmission on the second track run. He drove it with that knock sensor for almost a year.

With that sensor, the car ran 13s.......................

I need to get that transmission replaced.

Thanks
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Old Dec 19, 2007 | 02:11 AM
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yeah, 13s with cam and full boltons isn't exactly hauling
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Old Dec 19, 2007 | 03:18 AM
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Originally Posted by infinitebird
yeah, 13s with cam and full boltons isn't exactly hauling
Absolutely... I'm just thinking that if it went 13s with full retard, when it's running right it should be significantly faster...

How fast would you expect with full bolt ons?
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Old Dec 19, 2007 | 06:43 AM
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I don't have time to go into detail, but I made a 1/4 mile pass with by car pulling max timing. I gained 7 tenths and lost 9 mph on that pass, or maybe it was 9 tenths and seven mph. Anyway, it was a significant amount of performance that was lost.
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Old Dec 19, 2007 | 03:07 PM
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You should swap-out the factory LT1 PCM knock-module with an LT-4 knock-module. The LT-4 knock module will greatly improve the spark-retard issues. Check out this link.

http://www.projecttransam.com/projects1.asp

WD

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Old Dec 19, 2007 | 03:13 PM
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Originally Posted by The Engineer
You should swap-out the factory LT1 PCM knock-module with an LT-4 knock-module. The LT-4 knock module will greatly improve the spark-retard issues. Check out this link.
While this is a good idea, it will not fix his problem.

The knock sensor is different on OBD1 and OBD2, if the wrong sensor is used, the computer sets code 43 which means it cannot get a reading from the knock sensor.

The knock module is only utilized after the signal from the sensor is sent to the PCM. If the signal from the sensor is faulty, the knock module used is irrelevant, it will still pull the max timing. The knock sensor and module are sometimes confused. The module is what is inside the pcm, the sensor is located on the block on the lower right side.
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Old Dec 19, 2007 | 07:14 PM
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The LT-4 knock module "filters out" a band of frequencies from the knock sensor that can cause the PCM to retard the timing. Yes, depending of the year model (ODBI or ODBII), the sensors are different.

PCM tuning is probably the most effective tool, however, the knock module in the PCM is also a factor.

WD
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Old Dec 19, 2007 | 07:18 PM
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Instead of making another thread, I figured I'll ask my dumb question here. Sometimes in WoT I get pinging, but doesn't seem to pull any knock retard. So could I sit with my scanner next to me (I have a cool hand held that gives live sensor readings) and then just lightly tap the knock sensor with say a screwdriver handle, and see if it pulls any timing? I don't have any codes being thrown, but I just am wondering if it's either working right, or at all
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Old Dec 19, 2007 | 07:24 PM
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Originally Posted by The Engineer
PCM tuning is probably the most effective tool, however, the knock module in the PCM is also a factor.WD
Neither has any relevance to the OP who has the wrong KS for his PCM.
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Old Dec 19, 2007 | 07:50 PM
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Originally Posted by Formula350
Instead of making another thread, I figured I'll ask my dumb question here. Sometimes in WoT I get pinging, but doesn't seem to pull any knock retard. So could I sit with my scanner next to me (I have a cool hand held that gives live sensor readings) and then just lightly tap the knock sensor with say a screwdriver handle, and see if it pulls any timing? I don't have any codes being thrown, but I just am wondering if it's either working right, or at all
If you do this you want to tap on the block, not the sensor.
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Old Dec 19, 2007 | 10:21 PM
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Originally Posted by infinitebird
If you do this you want to tap on the block, not the sensor.
I haven't done this before...but it seems to me that it would be just a little hazardous to tap on the block near the sensor with the car running... Is this something you could do with ignition on, engine off?
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