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Detonation problems. HELP!!

  • Thread starter Thread starter matador91
  • Start date Start date Jun 27, 2009

matador91

Active Member
Feb 1, 2007
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Bothell
Jun 27, 2009
#1
  • Jun 27, 2009
  • #1
So.. I am trying to get my car running but now it has really bad detonation coming from the passenger side and it wont stay running I have to use the throttle to keep it running. Also, I have the timing set at 10 degrees. I can't for the life of me figure this out. I just installed a AFM B-41 cam, AFR 185 heads, RPM II intake, 30lb injectors, 75mm T/B, 4" power pipe, and a PMAS mass air calibrated. If you have any ideas or things for me to check for let me know. Thanks
 

ID89GT

10 Year Member
May 26, 2008
1,659
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49
Spokane Valley, WA
Jun 28, 2009
#2
  • Jun 28, 2009
  • #2
Possible vacuum leak? Idk.

I see your from Bothel, Is that the Bothel by Seattle WA or somewhere else?
 

94Blue302GT

Member
Oct 20, 2003
704
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Chicago
Jun 28, 2009
#3
  • Jun 28, 2009
  • #3
Check plugs and wires first.
The plugs can give you an indication as to what's happening.
Also, does your exhaust smoke a bit?
You can also try swapping out your dizzy, they seem to go out from time to time and can reek havoc on your motor. Plus, with the cam swap, it might be a tooth off, which could lead to crazy timing, even if you think you're set at 10*
 

jrichker

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Jun 28, 2009
#4
  • Jun 28, 2009
  • #4
Pinging or spark knock is not the same as detonation.

Pinging is preignition of the fuel air charge by some source of ignition other than the spark plug. The source of the ignition can be a hot spot in the combustion chamber such as carbon, a spark plug insulator, side electrode, or a sharp edge on a valve. It occurs before the spark plug can fire and while the piston is still on its upward movement towards TDC. That is the cause of the characteristic ping or ringing sound, much like shaking a coffee can full of BB’s.

Detonation is the uncontrolled explosion of the fuel air charge after the spark plug fires and starts to burn. In a properly running engine, the spark plug ignites the fuel air charge and it burns slowly and evenly across the combustion chamber, much like a fire as it burns its way across a grassy field. When detonation occurs, the ignited fuel air charge causes an increase in the combustion chamber pressure and temperature. The remaining fuel air charge that has not been burned self–ignites explosively causing tremendous heat and pressure. The source of secondary ignition can be the same as preignition, or can be simply due to the heat and pressure. Detonation is what damages engine parts because of the excessive heat and pressure.

Pinging can lead to detonation, and the results are the same: engine damage because of the excessive heat and pressure

So now that you know that there is a difference, what do you have?
 
B

BYRDPE

Founding Member
Nov 4, 1998
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Jun 28, 2009
#5
  • Jun 28, 2009
  • #5
Good explaination. Thanks for sharing.

Posted via Mobile Device
 

matador91

Active Member
Feb 1, 2007
107
31
38
Bothell
Jun 28, 2009
#6
  • Jun 28, 2009
  • #6
*
Check plugs and wires first.
The plugs can give you an indication as to what's happening.
Also, does your exhaust smoke a bit?
You can also try swapping out your dizzy, they seem to go out from time to time and can reek havoc on your motor. Plus, with the cam swap, it might be a tooth off, which could lead to crazy timing, even if you think you're set at 10*
Click to expand...


The dist. is a new MSD, and the car does smoke. For the cam swap I raised the #1 cyl. all the way up and then I put the timing chain on dot to dot.


So now that you know that there is a difference, what do you have?
Click to expand...

It would absolutely be detonation. Could a vacume leak cause this big of a problem?
 

jrichker

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#7
  • Jun 28, 2009
  • #7
matador91 said:
It would absolutely be detonation. Could a vacume leak cause this big of a problem?
Click to expand...

Yes.

A lean mixture can cause detonation.
 

roworld

Member
Feb 12, 2004
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baltimore md
Jul 29, 2010
#8
  • Jul 29, 2010
  • #8
94Blue302GT said:
Check plugs and wires first.
The plugs can give you an indication as to what's happening.
Also, does your exhaust smoke a bit?
You can also try swapping out your dizzy, they seem to go out from time to time and can reek havoc on your motor. Plus, with the cam swap, it might be a tooth off, which could lead to crazy timing, even if you think you're set at 10*
Click to expand...

You asked if his car smokes alittle. I resently installed a bbk ssi intake and im having probems ywith the car breaking up. I checked for vac leaks, change the distributor, and plug wires. This weekend ill change the plugs.
 

CDQICKGT

New Member
Jan 25, 2006
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fort hood, tx
Jul 29, 2010
#9
  • Jul 29, 2010
  • #9
Im not sure what the lift is on that cam but, did you check for proper PTV clearance. Just another possibiliy.
 
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