Second knock sensor? - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Reply
 
 
 
Thread Tools Search this Thread
Old 10-26-2003, 05:48 PM   #1
Senior Member
Certified GM nut
Thread Starter
 
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Thanks: 0
Thanked 0 Times in 0 Posts
DrJay is on a distinguished road
Default Second knock sensor?

I was just thinking about how important the knock sensor is and realized that the series I only has 1 knock sensor. It currently goes on the back of the engine up by the firewall but I know (Because it was accidentally placed there) that it will fit on the right side of the engine facing the radiator, there is actually a hole there for one. I'm wondering if I could buy another one, install it in the right side of the engine, splice into the other knock sensors wire, attach a diode between the wire and original sensor to keep voltage from the new sensor from going into the other one, stop by a junkyard and pick up a sensor clip then run the wire from the new sensor to the wire feeding the old one, and bada bing a knock sensor for each side.. Do-able? Hmmm I forget if its a single or dual wire setup. If its single the whole diode thing won't work because voltage needs to be able to return up the line and the diode would stop that...ahh any ideas?
DrJay is offline   Reply With Quote
Old 10-28-2003, 04:05 AM   #2
Senior Member
Posts like a Supercharger
 
Join Date: May 2003
Location: Columbus, OH
Posts: 163
Thanks: 0
Thanked 0 Times in 0 Posts
13secGTP is on a distinguished road
Default

I honestly dont think the PCM would interpret the info correctly. But it wouldn't be hard to disable the 2nd sensor incase the PCM went "DUH!"
13secGTP is offline   Reply With Quote
Old 10-28-2003, 02:01 PM   #3
Senior Member
Certified GM nut
Thread Starter
 
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Thanks: 0
Thanked 0 Times in 0 Posts
DrJay is on a distinguished road
Default

hrmm....if I'm thinking what I think you're thinking I don't think it'll work all that good either...ahh too much thought! Anyway the only problem I can think of off hand would be that the one it has now is designed to listen to every cylinder and send a response to the computer. Well if the computer gets two responses at the same time (well because of the extra wire it'll be 0.00000000000000000000000000000000001 second later) it might go "duh!" and really retard the timing. Also if I remember correctly the computer will compensate depending on how much voltage comes back. Maybe 5v = 1 deg retard and 6v = 2 deg. If both sensors detect the same knock and send the same voltage instead of a small 5v it'll be sending 10v resulting in more timing retard than necessary. Think about flying down the track and both sensors pick up a pretty big knock, huge voltage gets sent up the wire and the engine retards the timing entirely too much. That could be damaging on its own...hmmm maybe this is one that shoudl be left untouched
DrJay is offline   Reply With Quote
Old 10-28-2003, 02:27 PM   #4
Senior Member
True Car Nut
 
Join Date: Aug 2003
Location: Salina, KS
Posts: 5,246
Thanks: 0
Thanked 0 Times in 0 Posts
TrueWildMan is on a distinguished road
Default

Quote:
Originally Posted by DrJay
hrmm....if I'm thinking what I think you're thinking I don't think it'll work all that good either...ahh too much thought! Anyway the only problem I can think of off hand would be that the one it has now is designed to listen to every cylinder and send a response to the computer. Well if the computer gets two responses at the same time (well because of the extra wire it'll be 0.00000000000000000000000000000000001 second later) it might go "duh!" and really retard the timing. Also if I remember correctly the computer will compensate depending on how much voltage comes back. Maybe 5v = 1 deg retard and 6v = 2 deg. If both sensors detect the same knock and send the same voltage instead of a small 5v it'll be sending 10v resulting in more timing retard than necessary. Think about flying down the track and both sensors pick up a pretty big knock, huge voltage gets sent up the wire and the engine retards the timing entirely too much. That could be damaging on its own...hmmm maybe this is one that shoudl be left untouched
It'* strange. Electricity is still considered a theory because of some of the attributes that are in a seeming state of constant change. To me, this sounds like something that can only be best proven/disproven through trial and error. Unless you can get a hold of a true electrical guru...Andy knows alot...
TrueWildMan is offline   Reply With Quote
Old 10-28-2003, 11:04 PM   #5
Senior Member
True Car Nut
 
GAMEOVER's Avatar
 
Join Date: Aug 2003
Location: Racine Wi
Posts: 5,146
Thanks: 0
Thanked 0 Times in 0 Posts
GAMEOVER is on a distinguished road
Default

might work but i dont think any car has 2?
GAMEOVER is offline   Reply With Quote
Old 10-29-2003, 11:15 AM   #6
Senior Member
True Car Nut
 
Join Date: Aug 2003
Location: Salina, KS
Posts: 5,246
Thanks: 0
Thanked 0 Times in 0 Posts
TrueWildMan is on a distinguished road
Default

Quote:
Originally Posted by jr's3800
My 95 has 2 knock sensors.... Thats why it will give me a read out on cylinder missfire/*... I had a miss once and saw it was a cylinder 4 missfire... And damn it was right too... I have a sensor on the front bank and the rear bank
So, the PCM would be programmed to recieve and process two different impulses then??
TrueWildMan is offline   Reply With Quote
Old 10-29-2003, 05:44 PM   #7
Senior Member
True Car Nut
 
Join Date: Aug 2003
Location: Salina, KS
Posts: 5,246
Thanks: 0
Thanked 0 Times in 0 Posts
TrueWildMan is on a distinguished road
Default

Quote:
Originally Posted by jr's3800
I thought I was sure my 95 has 2 knock sensors in it... The next time I am under the car which will be soon, I look and see where the sensor/* are on the beast..
Oh, I'm not doubting you, I was just curious how it works...
TrueWildMan is offline   Reply With Quote
Old 10-29-2003, 11:15 PM   #8
Senior Member
True Car Nut
 
Join Date: Aug 2003
Location: Salina, KS
Posts: 5,246
Thanks: 0
Thanked 0 Times in 0 Posts
TrueWildMan is on a distinguished road
Default

.......

No, really, I wanna know how it works!!!

TrueWildMan is offline   Reply With Quote
Old 10-30-2003, 02:08 AM   #9
Senior Member
Posts like a Supercharger
 
Join Date: May 2003
Location: Columbus, OH
Posts: 163
Thanks: 0
Thanked 0 Times in 0 Posts
13secGTP is on a distinguished road
Default

For the Series II its 2 separate wires that go 2 the PCM. Each one give individual info to the PCM. You can disconnect one and be OK-disconnect both while having problems and you'll have more problems. I've tried it all with these little bastards . Trying to pull a new P/B with a spun bearing is next to impossible-damn Knock sensors-who needs them anyways.

I'm almost positive the Series I can be setup the same way-you just need have it proggrammed into the PCM and know where the wire goes (PIN).
But both into the same feed/PIN will cause some problems-just my .02

I do believe my '87 LeSabre has 2 knock sensors-similar location as the series II-IIRC.
13secGTP is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
knock knock knock L27Buick 1992-1999 7 09-17-2004 04:23 PM
Knock Knock continued (spun bearing) Spiral 1992-1999 5 05-25-2004 09:57 AM
Knock Knock, engine knock? Spiral 1992-1999 5 05-23-2004 10:08 PM
KR without Knock> Not even false knock? streetracer Performance, Brainstorming & Tuning 1 08-18-2003 02:08 PM
Knock Knock Tamara 1992-1999 11 01-31-2003 05:26 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:25 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.