[FAQ] Knock detection led system

gt4tified

New member
I tried this and it doesn't work on my car....apparently my tsc wire is reading a constant 6.9v when the car is on.....boost or no boost. What does this mean? Something wrong with my tvsv?
 

j-gt4specs

New member
gt4tified":2d0pdhfq said:
I tried this and it doesn't work on my car....apparently my tsc wire is reading a constant 6.9v when the car is on.....boost or no boost. What does this mean? Something wrong with my tvsv?

I still have yet to try this but uhm I think this should help you out if your aren't so sure which wire it is. Other than that I will get back to you on this.

ST185ECU.jpg
 

gt4tified

New member
This pinout diagram that you posted is for the USA SW20 GEN 2 (91). My alltrac engine is from a JDM SW20 gen 2 in which the pinout is different.

Check this link for the various pinouts:
http://sio.midco.net/asudbeck/pics/pinoutsfixed.jpg

So I did find the TSC wire quite easily using the above and did exactly as ur link described. I took some measurements with my multitester and will post the results here so anyone can have a go at what seems to be my problem.

I highly suspect thought that somehow my TVSV sensor (TSC) is not connected as when I switch my ignition on, the stock boost gauge needle goes all the way up and doesn't work.

Here are my tests & findings:
 

j-gt4specs

New member
Knockdetection.jpg


Here's a diagram that I made of how the setup should look. I did this yesterday and it worked as it should. When your car is off the green led is on, then when you start the car the red led goes on and stays on in idle and when your cruising. The green led goes on only when your boosting.
 

gt4tified

New member
So when you start the car the red led comes on and the green goes off until boost?

What happens is that my green is on just like yours when the car is off. When I turn the car on, both led's light (the red comes on but the green STAYS on). And I'm sure there is no knock on idle...what gives?
 

j-gt4specs

New member
gt4tified":124qp2bh said:
So when you start the car the red led comes on and the green goes off until boost?

What happens is that my green is on just like yours when the car is off. When I turn the car on, both led's light (the red comes on but the green STAYS on). And I'm sure there is no knock on idle...what gives?

HmMm I have no clue are you sure you got the right wiring and double check just to be sure but I'll take pictures of what I did, cause its as I said the green light only comes on when the car is off or at the point of boost then turns off when your not boosting. Only one led can be on which should be the red led when your car is on but when its off the green is on but the red is barely lit that you cant notice.
 

gt4tified

New member
Well I just checked my TVSV and the wires were disconnected. The clip is on the sensor but its not wired to anything. Is it that these wires should just carry a 12v to it and where does it connect to the TPC wire on the ecu. Thanks. God only knows what my TPC wire is connected to right now!
 

gt4tified

New member
Just now wondering....would this detection system still work if I disconnect the TVSV to use an aftermarket boost controller?
 

urbandork

New member
gt4tified":3m5vd0gz said:
Just now wondering....would this detection system still work if I disconnect the TVSV to use an aftermarket boost controller?

yes it will however it will not be able to adjust the boost from normal boost to safe boost levels. Im running an HKS EVC IV and the led knock det. dyi thing still works.

on a side note the led system doesnt work the same with a 3rd gen ecu

apparently the 3rd gen ecu uses some kind of pulse modulating system which means that when the car is at boost and the ecu has ok'ed everything the green led wont stay on ... instead the red and the green led will flash back and forth..... if the car is in safe mode the red LED will still stay on.... I did this by deliberately throwing a cel 54 by disconnected the water level sensor.
 

Charly003

New member
I've a question about this very nice and cheap modification!

I've a 1990 JDM GT4, one of the first to be built (Before Jan 1990). Wondering how can I figure what's my ECU model to find out my TCP pin?

All what I need to do is tap a cable to that TCP pin to leds right?
 

MXP_57

New member
I have one question, does this mod works for the 1st and 2nd gears aswell? or is it only for the 3 last gears?

Thanks!
 
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