General Miata Chat A place to talk about anything Miata

DIY knock detecting tool

Thread Tools
 
Search this Thread
 
Old 06-14-2007, 05:33 PM
  #1  
Newb
Thread Starter
 
Piranah's Avatar
 
Join Date: May 2007
Location: Alamogordo, NM
Posts: 43
Total Cats: 0
Default DIY knock detecting tool

So a friend of mine that runs a shop in town shows me the inside of his cifvic the othere day, I look inside and find a stethascope on his console thats connected to a tube running under the firewall.
"What's that for?" I asked. He says, "Oh, it's a det-can, I use it to listen for knock when I'm driving and tuning"
I couldn't believe it, all it was was a stethascope, some plastic hose, and a copper pipe hooked on to the block, and you can hear the internals perfectly. Worked so good I put one in my WRX and detected knock that my knock sensor didn't pick up.
Anyone heard of this or want to know more? If this is new to some people I might do a DIY write-up on it soon.
Piranah is offline  
Old 06-14-2007, 05:51 PM
  #2  
Elite Member
iTrader: (12)
 
neogenesis2004's Avatar
 
Join Date: Aug 2006
Posts: 4,413
Total Cats: 20
Default

I have one sorta like that. Only mine is a microphone from one of those cheap *** spy thingys that amplifies nearby sounds. I superglued it to a clamp from an old pair or jumper cables. I just listen to knock through headphones.

Funny thing is that I wasn't using them when my motor blew :(
neogenesis2004 is offline  
Old 06-14-2007, 05:53 PM
  #3  
Elite Member
iTrader: (14)
 
jayc72's Avatar
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,908
Total Cats: 1
Default

Originally Posted by neogenesis2004
Funny thing is that I wasn't using them when my motor blew :(

Doh! Knock sensor FTW!
jayc72 is offline  
Old 06-14-2007, 06:41 PM
  #4  
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
Default

I might try this.
hustler is offline  
Old 06-14-2007, 06:48 PM
  #5  
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
Default

That's "old school". I've seen my dad do that many times.
__________________
Chief of Floor Sweeping, DIYAutoTune.com & AMP EFI
Crew Chief, Car Owner & Least Valuable Driver, HongNorrthRacing

91 Turbo | 10AE Turbo | 01 Track Rat | #323 Mazda Champcar

Originally Posted by concealer404
Buy an MSPNP Pro, you'll feel better.
Ben is offline  
Old 06-14-2007, 07:39 PM
  #6  
Junior Member
 
Exhondaman's Avatar
 
Join Date: Mar 2007
Location: SoCal
Posts: 283
Total Cats: 1
Default

Question is, what are you doing to control the knock?

Cool trick,btw.
Exhondaman is offline  
Old 06-14-2007, 08:01 PM
  #7  
Elite Member
iTrader: (12)
 
neogenesis2004's Avatar
 
Join Date: Aug 2006
Posts: 4,413
Total Cats: 20
Default

you let off the gas, thats how. With this method you will hear knock before a knock sensor would even pick up on it. Ears = more sensitive than knock sensor.
neogenesis2004 is offline  
Old 06-14-2007, 08:01 PM
  #8  
:(
iTrader: (7)
 
magnamx-5's Avatar
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,255
Total Cats: 4
Default

Lifting noting, and fixing it later, or tweaking the ECU duh
magnamx-5 is offline  
Old 06-14-2007, 08:29 PM
  #9  
Elite Member
iTrader: (12)
 
neogenesis2004's Avatar
 
Join Date: Aug 2006
Posts: 4,413
Total Cats: 20
Default

I guess I didn't answer his question all the way.

It is simply a tuning tool, not something you keep on the car all the time.
neogenesis2004 is offline  
Old 06-15-2007, 01:21 AM
  #10  
Elite Member
iTrader: (5)
 
akaryrye's Avatar
 
Join Date: Jul 2006
Location: Central California
Posts: 2,535
Total Cats: 3
Default

That Is pretty cool, i might hook up something like this when I get the car back on the road
akaryrye is offline  
Old 06-15-2007, 01:40 AM
  #11  
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,091
Total Cats: 7
Default

My dad has something like this as well. He has another tool that has a solid rod probe at the other end. If you have some kind of engine noise you can stick that probe on different parts of the motor too find out where it's coming from. Kind of like using a vac line to find air leaks, you use the probe to find mechanical noise.
cjernigan is offline  
Old 06-15-2007, 02:34 AM
  #12  
Elite Member
iTrader: (5)
 
akaryrye's Avatar
 
Join Date: Jul 2006
Location: Central California
Posts: 2,535
Total Cats: 3
Default

Long screwdriver up to the ear works too
akaryrye is offline  
Old 06-15-2007, 02:56 AM
  #13  
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,091
Total Cats: 7
Default

Originally Posted by akaryrye
Long screwdriver up to the ear works too
Same idea Def more readily available.
cjernigan is offline  
Old 06-15-2007, 10:09 AM
  #14  
Miotta FTW!
iTrader: (24)
 
Splitime's Avatar
 
Join Date: Jun 2006
Location: Chicagoland, IL
Posts: 4,290
Total Cats: 31
Default

I use an electronic version. Find a typical bosch knock sensor, get an obd1 injector plug.. or keep the plug from the sensor and splice it into a stereo jack cable. Buy a cheap little amp/speaker unit from radiashack and use that or headphones from it.

I can hear the fuel priming in the rail at startup.... its awesome.
Splitime is offline  
Old 06-15-2007, 04:41 PM
  #15  
Newb
Thread Starter
 
Piranah's Avatar
 
Join Date: May 2007
Location: Alamogordo, NM
Posts: 43
Total Cats: 0
Default

Originally Posted by cjernigan
My dad has something like this as well. He has another tool that has a solid rod probe at the other end. If you have some kind of engine noise you can stick that probe on different parts of the motor too find out where it's coming from. Kind of like using a vac line to find air leaks, you use the probe to find mechanical noise.

I used the stethascope end from that same thing. I got it at autozone. The great thing about the setup I'm using is that you can use it when the car is moving.
Piranah is offline  
Old 06-16-2007, 06:00 PM
  #16  
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,482
Total Cats: 372
Default

Originally Posted by akaryrye
Long screwdriver up to the ear works too
I'd like to see that in use during a boost run
m2cupcar is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
nick470
MEGAsquirt
7
06-16-2017 01:53 PM
LucaCarMods
Build Threads
11
02-14-2016 06:13 AM
brandonbkd
MEGAsquirt
0
09-28-2015 11:52 PM
EErockMiata
MEGAsquirt
6
09-24-2015 09:49 AM



Quick Reply: DIY knock detecting tool



All times are GMT -4. The time now is 06:07 PM.