JohnKoaWood

I have forgotten more about soldering.... I don't mind tiny, my iron has a micro tip on it... makes it useful for poking into tight places...



I have just about finished the write up, just a few more pictures, and posting it with all the pictures... should be able to wrap it up tomorrow..

Van

Actually around 9 or 10 PSI. And, yes, it's pump gas.

Great Stuff, John - you're a wealth of knowledge.

For those that don't know about the FQS switch, I found this: http://members.rennlist.com/951_racerx/FQS-adjust.html

I'll pull my DME out and see what setting it's on.

Van

P.s. I was looking though my data again. In that corner, you're right, engine speed is always about 5400 RPM. However, other corners have similar knock counts right after WOT, but at different RPMs.

joeytoad83

i managed to break mine already lol, it will power up but wont count o well time to order another

JohnKoaWood

Did you put a push button between the contact and pin 1 or just a wire?

The pad needs momentary contact to clear the count, but if shorted to pin 1 is in a constant reset...

I have done 2 of them now, with no issues...

Write up is almost finished...

joeytoad83

i have nothing there right now i took it off. i thinks its cause i hooked it up backwards.

JohnKoaWood

How to modify your Curtis counter to be able to reset it and add a backlight while you’re in there.

What you will need:
1 Curtis counter P/N 703DN00100512D


2 220 Ohm resistors, mini size Radio Shack P/N 271-011
1 Submini Pushbutton momentary switch Radio Shack P/N 275-1571
1 Micro Lamp Radio Shack P/N 272-1092
Soldering Iron
Desoldering Wick
Solder
Heat Shrink, various sizes
Heat gun (for heat shrink)
Approx 10 inches of 14 gauge wire (cut into 4 equal pieces, both ends stripped)
Knife (X-Acto worked well for me, but I have 10 of them or so around the house)

Open your Counter up by cutting with the knife blade along the seam between the face of the counter and the back of the housing. Don’t worry if it sounds like it is breaking, they glue it on for a reason, to keep you from removing the face.


Remove face, seal, and glass from housing, discard glass unless you have a glass cutter handy and feel like trying to cut it to work… A CD jewel case works just fine as a replacement and the plastic is easier to cut.


Desolder rear terminals from pins inside the terminal base, apply LIGHT pressure to the counter circuitry if needed while applying heat to the terminals to get the circuitry to release. The housing WILL take some light melting during de-soldering, don’t worry, you will never see this when you install it in your car…



Install 1 220 Ohm resistor to the 2nd solder pad above Pin 4 on the circuit, this is for the reset function, Curtis installs a resistor on the circuit between the 2 solder pads to enable reset, but we want a button on the face of the gauge right?


Solder a wire to the other side of the resistor, then cut a length of heat shrink to cover the resistor all the way from the wire to the circuit card. This will prevent inadvertent shorting.


Install 2 more pieces of wire to pin 1, install 1 wire to pin 2.


Slip 2 more pieces of heat shrink onto ONE wire on pin one, and the wire you soldered onto the resistor that is connected to the circuit board, make them ½ inch long or so..
Solder 1 switch between the 2 wires you just put the heat shrink onto, shrink the heat shrink.


Solder 1 220 ohm resistor to one side of your micro bulb, then solder the bulb to the 2 wires on pins 1 and 2 of the circuit card.


Glue your bulb to the side of the LCD display where the black metal cover of the LCD is open to the side (right side between pins 1 and 2).



Drill a hole into the face of the gauge to allow you to install the switch into the face.



Install the switch to the face of the gauge. Discard the small locking washer, as it will not be needed for this application.

Re-insert the circuit board to the rear housing, tucking all the wires under the circuit card. Then solder pins 1, 2, and 3 into the connections on the back of the housing.

Install cut jewel case or cut glass on top of LCD, and reglue face onto the gauge. (I used super glue, but any fast drying adhesive should work fine.)


Install to your car in place of your choice, connecting as directed by instructions included with the gauge. Reset whenever you want, and be able to read it at night…..


Feel free to PM me if you encounter any issues, Or E-mail johnkoawood@aol.com

Scott H

Assembled my counter today with your walkthrough and it works like a charm! Will glue the face back on and install it in the car tomorrow but wanted to say thanks!

If anyone has any reservations about doing this, don't worry, it's like a 3/10 on the difficulty scale and a 2 beer job at the max.

JohnKoaWood

Scott H

One question: why'd you put a 220ohm resistor on the mini lamp? It made it really dim for me, so much so that it was near useless. I have to buy another 2 pack (or possibly an LED) cuz I buggered up both, friggin tiny *** wires. I mounted the reset switch out the right side of the housing and drilled a spot for the lamp right in the middle of where it says Curtis. I'm not going to run this thing 100% of the time so I used a 3 prong Molex connector and a hacked up 6 foot USB cord wired into the KLR diagnostic plug so I can install and remove the counter as needed and just tuck the cord for it behind the DME/KLR.

I got bored/couldn't sleep and installed it, took a 20 minute drive with a couple WOT runs to 80mph through the gears and got only 3 counts, which were probably low load hits. I'll wire in a Hobbs switch at 5psi or so later on so I only capture the high load knocks.

JohnKoaWood

Awesome.. and I included the resistor on teh lamp to prevent blowing the lamp after the whole thing was glued back together (current limiting) as I wired the power leads to the stereo circuit in the dash (on teh switched lead).

I love seeing feedback on this, as several have cracked open their counters and added the reset or lamp or both.. I found the lamp was dime, but more than sufficient to be readable at night but not glaring enough to be a distraction! you could easily omit the resistor, and many have omitted the lamp all together!

HOWEVER it is important the resistor be on the switch, as if it is omitted it WILL fry the counter the first time you hit the switch.. it only needs to sense 12VDC for the reset, and will overcurrent in the blink of an eye.. I destroyed several counters this way while working out the fixed values to go with for flawless function.

Scott H

Sounds good. I didn't know if the bulb was getting too hot with prolonged use without the resistor or burning out prematurely. I may build a few more of these just because I'm local to Skycraft Surplus (best store in the world) and need a cheap project to kill some time. Plus my first attempt looks like it was assembled by a drunk...

JohnKoaWood

Its OK, first one or two I did ended up looking like they were done by Ray Charles taking instructions from Hellen Keller while she was listening to a how to on tape!

Voith

Time for a little thread resurrection batman.

Is there any knock counting system, that is completely standalone and works by directly bolting sensor to block, has tuning and logging / displaying capability?

Rogue_Ant

J&S:

http://www.jandssafeguard.com/index.html