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From: Jack on 5 Dec 2008 17:30


I have a brand new out of the box (not rebuilt) Holley 2280 replacement
carburetor bolted onto a 1987 Dodge Dakota 3.9L V6 engine. The original
was a Holley 6280, which is the feedback version of the 2280. The
feedback solenoid for the 6280 is no longer available, so when mine went
south, I opted for the 2280 as a replacement.

I am getting snow white insulators on the plugs.

I increased the main jets approximately 40%. No change.

I backed out the idle mixture screws about 3/4 beyond lean best idle
setting. No change.

I raised the float level about 1/8 inch above specs. No change

I decreased both the main air bleeds and the idle air bleeds by more
than 50%. No change. Plug insulators are still snow white after all
driving conditions.

Manifold vacuum reads a perfect 19-20 inches Hg at warm idle. All lines
pass a visual test and vacuum test.

I checked the EGR system. It works perfectly. I have a vacuum meter
hooked to the vacuum line that operates the EGR valve. It reads good.
The temperature sensor that kicks in the vacuum soon after startup is
working fine. Dashboard temp meter shows normal temp at all speeds and
loads.

Mileage on the freeway is great, over 21 mpg on a recent trip of 200
miles. Mileage around town is so-so, 15 mpg tops (auto tranny). Truck
has super heavy suspension with rack and big box of tools.

Engine runs smooth and strong from dead stop to freeway speeds. No
hesitation or flat spots anywhere. I have absolutely no driveability
issues whatsoever.

All ignition parts are new. Timing is dead on spec.

How long should plugs be run before they turn toasty tan if
stoichiometric is at 14.7 to 1?

In another vehicle I have seen plugs turn from sooty under very rich
conditions to toasty tan under correct conditions in a *very* short
period of time, like minutes, not hours.

Any suggestions as to what might be causing this plug condition?

I am out of guesses. Absolutely nothing makes sense.

Thanks,
Jack

From: Tegger on 5 Dec 2008 20:54
Jack <Jack(a)the_wild_kingdom.com> wrote in news:uXh_k.8787$yr3.5373
@nlpi068.nbdc.sbc.com:

>
>
> I have a brand new out of the box (not rebuilt) Holley 2280 replacement
> carburetor bolted onto a 1987 Dodge Dakota 3.9L V6 engine. The original
> was a Holley 6280, which is the feedback version of the 2280. The
> feedback solenoid for the 6280 is no longer available, so when mine went
> south, I opted for the 2280 as a replacement.
>
> I am getting snow white insulators on the plugs.



Are there deposits of discernible thickness on the insulators?


--
Tegger

From: Steve W. on 5 Dec 2008 21:38
Jack wrote:
>
> I have a brand new out of the box (not rebuilt) Holley 2280 replacement
> carburetor bolted onto a 1987 Dodge Dakota 3.9L V6 engine. The original
> was a Holley 6280, which is the feedback version of the 2280. The
> feedback solenoid for the 6280 is no longer available, so when mine went
> south, I opted for the 2280 as a replacement.
>
> I am getting snow white insulators on the plugs.
>
> I increased the main jets approximately 40%. No change.
>
> I backed out the idle mixture screws about 3/4 beyond lean best idle
> setting. No change.
>
> I raised the float level about 1/8 inch above specs. No change
>
> I decreased both the main air bleeds and the idle air bleeds by more
> than 50%. No change. Plug insulators are still snow white after all
> driving conditions.
>
> Manifold vacuum reads a perfect 19-20 inches Hg at warm idle. All lines
> pass a visual test and vacuum test.
>
> I checked the EGR system. It works perfectly. I have a vacuum meter
> hooked to the vacuum line that operates the EGR valve. It reads good.
> The temperature sensor that kicks in the vacuum soon after startup is
> working fine. Dashboard temp meter shows normal temp at all speeds and
> loads.
>
> Mileage on the freeway is great, over 21 mpg on a recent trip of 200
> miles. Mileage around town is so-so, 15 mpg tops (auto tranny). Truck
> has super heavy suspension with rack and big box of tools.
>
> Engine runs smooth and strong from dead stop to freeway speeds. No
> hesitation or flat spots anywhere. I have absolutely no driveability
> issues whatsoever.
>
> All ignition parts are new. Timing is dead on spec.
>
> How long should plugs be run before they turn toasty tan if
> stoichiometric is at 14.7 to 1?
>
> In another vehicle I have seen plugs turn from sooty under very rich
> conditions to toasty tan under correct conditions in a *very* short
> period of time, like minutes, not hours.
>
> Any suggestions as to what might be causing this plug condition?
>
> I am out of guesses. Absolutely nothing makes sense.
>
> Thanks,
> Jack
>

What has your water temp been?
What has the timing been doing?

What you may be seeing is the alcohol content of the fuel cleaning the
plugs as well.

You may try dropping a heat range or two on the plugs and see what you get.
From your driveability report it sounds like your engine and the carb
are pretty close out of the box. If the engine temps look OK and it
isn't knocking I would try the plugs and see if you can cool them down.

--
Steve W.
Near Cooperstown, New York


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From: TigerLuck on 6 Dec 2008 09:56
Tegger wrote:
> Jack <Jack(a)the_wild_kingdom.com> wrote in news:uXh_k.8787$yr3.5373
> @nlpi068.nbdc.sbc.com:
>
>>
>> I have a brand new out of the box (not rebuilt) Holley 2280 replacement
>> carburetor bolted onto a 1987 Dodge Dakota 3.9L V6 engine. The original
>> was a Holley 6280, which is the feedback version of the 2280. The
>> feedback solenoid for the 6280 is no longer available, so when mine went
>> south, I opted for the 2280 as a replacement.
>>
>> I am getting snow white insulators on the plugs.
>
>
>
> Are there deposits of discernible thickness on the insulators?


No, none. Very thin light grey deposits on the bendable electrode though.
From: TigerLuck on 6 Dec 2008 10:05
Steve W. wrote:
> Jack wrote:
>> I have a brand new out of the box (not rebuilt) Holley 2280 replacement
>> carburetor bolted onto a 1987 Dodge Dakota 3.9L V6 engine. The original
>> was a Holley 6280, which is the feedback version of the 2280. The
>> feedback solenoid for the 6280 is no longer available, so when mine went
>> south, I opted for the 2280 as a replacement.
>>
>> I am getting snow white insulators on the plugs.
>>
>> I increased the main jets approximately 40%. No change.
>>
>> I backed out the idle mixture screws about 3/4 beyond lean best idle
>> setting. No change.
>>
>> I raised the float level about 1/8 inch above specs. No change
>>
>> I decreased both the main air bleeds and the idle air bleeds by more
>> than 50%. No change. Plug insulators are still snow white after all
>> driving conditions.
>>
>> Manifold vacuum reads a perfect 19-20 inches Hg at warm idle. All lines
>> pass a visual test and vacuum test.
>>
>> I checked the EGR system. It works perfectly. I have a vacuum meter
>> hooked to the vacuum line that operates the EGR valve. It reads good.
>> The temperature sensor that kicks in the vacuum soon after startup is
>> working fine. Dashboard temp meter shows normal temp at all speeds and
>> loads.
>>
>> Mileage on the freeway is great, over 21 mpg on a recent trip of 200
>> miles. Mileage around town is so-so, 15 mpg tops (auto tranny). Truck
>> has super heavy suspension with rack and big box of tools.
>>
>> Engine runs smooth and strong from dead stop to freeway speeds. No
>> hesitation or flat spots anywhere. I have absolutely no driveability
>> issues whatsoever.
>>
>> All ignition parts are new. Timing is dead on spec.
>>
>> How long should plugs be run before they turn toasty tan if
>> stoichiometric is at 14.7 to 1?
>>
>> In another vehicle I have seen plugs turn from sooty under very rich
>> conditions to toasty tan under correct conditions in a *very* short
>> period of time, like minutes, not hours.
>>
>> Any suggestions as to what might be causing this plug condition?
>>
>> I am out of guesses. Absolutely nothing makes sense.
>>
>> Thanks,
>> Jack
>>
>
> What has your water temp been?

Dashboard coolant temp gauge shows normal temp at all speeds and loads.

> What has the timing been doing?

I just checked timing. It was at 8 BTC. Spec is 7 BTC. I adjusted to spec.

>
> What you may be seeing is the alcohol content of the fuel cleaning the
> plugs as well.

Wouldn't all engines in my area, using the same gas, have plugs with
snow white insulators?

>
> You may try dropping a heat range or two on the plugs and see what you get.

Same stock plugs that I have always used. Champion RN12YC

> From your driveability report it sounds like your engine and the carb
> are pretty close out of the box. If the engine temps look OK and it
> isn't knocking I would try the plugs and see if you can cool them down.

I'll try it.

Thanks,
Jack
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