knock sensors

Gene,
Are you making these setups or are you using the Caspro unit? My Caspro
engine knocks BAD on occasion. Had John Nepper here this weekend and we
heard it BIG TIME! Sounded like the thing had a sledge hammer in there
somewhere at low idle. I upped the idle a bit and it went right away. Pretty
spooky.... even though it's Halloween.
Let me know what you think of your setup. I gotta do something ...

Nate '75GB (I hear u knockin' but u can't come in...) Omaha

>

Date: Sun, 31 Oct 1999 11:00:00 -0800
From: gene
Subject: GMC: knock sensors

Please go read the stuff I have on the web page and let me know if you have
any suggestions. The reference there is what I am going to use unless
someone has a better answer.
gene

Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Nate,

Have you adjusted the timing since I drove the coach? The "sweet spot" was
so narrow that I wondered what would happen over time. Did it change
timing, did the window get wider or did it start to overlap?

What about fuel rating, etc.

I've only been able to scann through much of the net posts having so much
else to answer. How is the motor doing and did you send the dist. back to
Chuck for a check out?

See ya,

Jim Bounds
- -------------------

>In a message dated 10/31/1999 8:09:44 PM Central Standard Time,

>
>> My Caspro
>> engine knocks BAD on occasion. Had John Nepper here this weekend and we
>> heard it BIG TIME! Sounded like the thing had a sledge hammer in there
>> somewhere at low idle.
>
>Nate
>
>Please understand that it has been years since I worked on engines.
>Also understand I get real anal when it comes to engines. Here are my
>thoughts and nothing more. Take them as the ranting of an old man.
>Engine knock should not occur at low idle. This is something that
>should occur when the engine is under a load. First get a timing light
>on it. Make sure it is at 8d before TDC. If it is a lot higher start checking
>the vacuum advance and the centrifugal advance. Oh yeah take off and plug
>vacuum line to vacuum advance. Make sure neither one is sticking. Now
>here is the test you dont want to do. Make sure she is warm. Rev the engine
>to about 2 grand and get off it. If she knocks coming back down get
>somebody to plasti-guage the lower end. I did not want to say that.
>
>Take Care
>Arch
>
>
 
I am starting to investigate these sensors primarily to listen to spark
knock/ping which is preignition caused by fuel,timing,etc problems. These
sensors have been so mysterious I want to see if we can use them to resolve
some issues like, does propane injection really help.

Your knocks don't need a sensor, you can really hear them. I usually use a
broom stick stuck in my ear to locate these sorts of noises. When you
touch the item like a pump, alternator, etc the noise will travel up the
broom stick and you can isolate where the noise is from.

This must be really scary with a new engine, keep us informed.
gene

>Gene,
> Are you making these setups or are you using the Caspro unit? My Caspro
>engine knocks BAD on occasion. Had John Nepper here this weekend and we
>heard it BIG TIME! Sounded like the thing had a sledge hammer in there
>somewhere at low idle. I upped the idle a bit and it went right away. Pretty
>spooky.... even though it's Halloween.
> Let me know what you think of your setup. I gotta do something ...
>
>Nate '75GB (I hear u knockin' but u can't come in...) Omaha
>
>>
>
>Date: Sun, 31 Oct 1999 11:00:00 -0800
>From: gene
>Subject: GMC: knock sensors
>
>Please go read the stuff I have on the web page and let me know if you have
>any suggestions. The reference there is what I am going to use unless
>someone has a better answer.
>gene
>
>
>Genef -- 77PB/ore/ca
>GMC MOTORHOME INFORMATION
>mr.erf
>http://www.california.com/~eagle/
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Just my 5 cents but if you have a knock at idle it does not sound like
preignition. Sounds like a main bearing to me.

>Gene,
> Are you making these setups or are you using the Caspro unit? My Caspro
>engine knocks BAD on occasion. Had John Nepper here this weekend and we
>heard it BIG TIME! Sounded like the thing had a sledge hammer in there
>somewhere at low idle. I upped the idle a bit and it went right away. Pretty
>spooky.... even though it's Halloween.
> Let me know what you think of your setup. I gotta do something ...
>
>Nate '75GB (I hear u knockin' but u can't come in...) Omaha
>
>>
>
>Date: Sun, 31 Oct 1999 11:00:00 -0800
>From: gene
>Subject: GMC: knock sensors
>
>Please go read the stuff I have on the web page and let me know if you have
>any suggestions. The reference there is what I am going to use unless
>someone has a better answer.
>gene
>
>
>Genef -- 77PB/ore/ca
>GMC MOTORHOME INFORMATION
>mr.erf
>http://www.california.com/~eagle/
>
>
>
 
Just talked Chuck S. and he said since the oil pressure seems good he
doubted it was an engine problem. Sounds like the torque converter might be
loose to him. He said it's easy to check and thats where he'd start. I'll
try that this weekend. Yeah, Arch... I hope not too!

Nate 75GB (worried in) Omaha

>>

Tom

Here we go again-----we agree. Maybe we should limit ourselves to
things inside the engine. Now on my last rebuild it was a rod bearing.
That was more like a ball peen hammer on the block. Since Nate says
it is more like a sledge hammer I will even concede to you on the main
bearing idea. I was just trying to keep it as open as possible. I sure hope
not but I dont like the sound of this.

Take Care
Arch 76 GB IL
 
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