#21  
Old 12-07-2019, 03:47 PM
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sjdiesel sjdiesel is offline
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Sorry guys busy week.
Here is a better look at plug #1. This after 120 miles of driving this week. 50/50 highway/city. Didn’t have a chance to fill it up yesterday to check mileage but it seems up slightly.
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Koerner built 468 with Edelbrock RP’s 315cfm by Butler, Luanti Voodoo HR 20510713, 4l80e, Holley Terminator EFI
  #22  
Old 12-07-2019, 03:53 PM
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Quote:
Originally Posted by Navy Horn 16 View Post
If I had all of my carb issues to do over again, the first thing I would have done would be to weld a bung into my exhaust to hook up a wideband AFR gauge. You don't even have to find a place to permanently mount it in the car (though mine is in one of the old AC vents of the TA bezel). After you get your carb dialed in, you can take it all out if you want the car looking clean and put a plug in the bung and the whole setup on your shelf.

Forget about reading plugs, that's 9 parts voodoo and one part science. You can be lean at idle, rich at cruise, and lean with the secondaries...what is that plug going to look like?? No idea? Me either.

With the wideband you can know exactly what your AFR is in every driving condition and make the necessary adjustments.
This is something I have been thinking about. any recommendations on which AFR to use?

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1967 GTO
Koerner built 468 with Edelbrock RP’s 315cfm by Butler, Luanti Voodoo HR 20510713, 4l80e, Holley Terminator EFI
  #23  
Old 12-08-2019, 09:04 AM
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shaker455 shaker455 is offline
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I usually recommend AEM widebands as they are not expensive and they get the job done.

https://www.amazon.com/AEM-30-0300-W...07150557&psc=1

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Last edited by shaker455; 12-08-2019 at 09:13 AM.
  #24  
Old 12-09-2019, 07:13 AM
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For only 120 miles of run time plug is far too brown in color if it went into to the motor new, so indicating a very rich condition !

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  #25  
Old 12-09-2019, 08:23 AM
jamaca85 jamaca85 is offline
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i have an 850 on my street driven firebird with the 455...has 3.42 gears,,, 75 front jets with pv.. gets me around 12mpg. i would check the carb maybe your front metering rods are getting stuck

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  #26  
Old 12-09-2019, 09:38 AM
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This is the best way to operate your choke.. https://www.summitracing.com/parts/r...iABEgJ-P_D_BwE

Those electric chokes never worked right for me..

  #27  
Old 12-13-2019, 06:53 PM
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Ok so I bought an AEM A/F ratio gauge and installed it today. I pulled the carb apart and measured a few things after reading Cliffs Q-jet book. the front metering rods move freely. I have 74 jets in the primaries

Here are some numbers after driving the car with the new AFR gauge:
Cruise ~ 13.2-13.5
Mild acceleration from a stop to 55mph ~ 13.8-13.3
WOT ~ in the high 12’s low 13’s
Deceleration ~ in the 12’s a couple times in the high 11’s

From my reading the deceleration should get leaner, not richer....

For those that are running an AFR gauge, how close to 14.7 are you getting?

So what are your thoughts?

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1967 GTO
Koerner built 468 with Edelbrock RP’s 315cfm by Butler, Luanti Voodoo HR 20510713, 4l80e, Holley Terminator EFI
  #28  
Old 12-13-2019, 08:20 PM
Formulas Formulas is offline
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Spark curve?

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  #29  
Old 12-13-2019, 08:37 PM
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Are you running any octane booster in your gas? If so, that will color the plugs a rusty brown color. Also, focus on the cruise and full throttle air fuel ratios. Deceleration numbers can be misleading. Based on your AF numbers I would lean up the primary side a little and put a little richer secondary metering rod in it.

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  #30  
Old 12-14-2019, 09:37 AM
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Quote:
Originally Posted by sjdiesel View Post
Ok so I bought an AEM A/F ratio gauge and installed it today. I pulled the carb apart and measured a few things after reading Cliffs Q-jet book. the front metering rods move freely. I have 74 jets in the primaries

Here are some numbers after driving the car with the new AFR gauge:
Cruise ~ 13.2-13.5
Mild acceleration from a stop to 55mph ~ 13.8-13.3
WOT ~ in the high 12’s low 13’s
Deceleration ~ in the 12’s a couple times in the high 11’s

From my reading the deceleration should get leaner, not richer....

For those that are running an AFR gauge, how close to 14.7 are you getting?

So what are your thoughts?
Looks like your AFR number are safe and not bad at all.
What size are your primary metering rods?

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  #31  
Old 12-15-2019, 06:36 PM
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sjdiesel sjdiesel is offline
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Quote:
Originally Posted by shaker455 View Post
Looks like your AFR number are safe and not bad at all.
What size are your primary metering rods?
Primary metering rods measure .035”

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Sean
1967 GTO
Koerner built 468 with Edelbrock RP’s 315cfm by Butler, Luanti Voodoo HR 20510713, 4l80e, Holley Terminator EFI
  #32  
Old 12-15-2019, 07:24 PM
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Greg Reid Greg Reid is offline
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Quote:
Originally Posted by sjdiesel View Post
Primary metering rods measure .035”
I'm no expert but 35 sounds pretty rich for 74 jets doesn't it?
I'm thinking more like 44...

Sent from my moto g(6) play using Tapatalk

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Last edited by Greg Reid; 12-15-2019 at 07:37 PM.
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