I'm not a Holly expert. I've worked on a few quadrajets. Here's some
general
troubleshooting suggestions/comments:
Your idle circuit is not working right. You've stated that it is
unresponsive to the idle mixture screws. Are the tips of the screws sharp
or dull? If you screw in an idle mixture screw in too far it can dull the
point. Are they the correct ones for length? Some screws are shorter than
others. Maybe you have the wrong length ones. I know that there is a
difference in length for emission vs non emission idle screws.
Could be that the main jets were rich to compensate for the idle circuit
is
not working... You may have to open up the carb to find out why the idle
circuit is not working.
BTW what model Holley is it? Could it be one made specifically for racing?
James Drinkwater wrote:
> Thanks for the reply, Steve. But, I considered the accelerator shot
and
> that can't be it. Let me describe the situation better. Interstate
> cruise is the most obvious.
> So, there I am on the interstate cruising along at about 60mph. The
> engine's revving and the mixture's doin' alright. If I press a little
on
> the accelerator smoothly to get up to 65 or 70, it goes way lean and
holds
> in a lean condition until I get up to the desired speed and ease out of
> the throttle a tad to hold it.
> I'm not "kickin' it" to need the pump shot or so heavy that the vacuum
> drops enough that I'd need the Power Valve; just a little more throttle.
> If I do continue to roll into the throttle for heavier acceleration, it
> don't see the PV overcome the lean condition.
> Perplexing, huh?
> Drink
> "Steve Austin" <saustin4@[EMAIL PROTECTED]
> wrote in message
> news:45d79695$0$28119$4c368faf@[EMAIL PROTECTED]
>> James Drinkwater wrote:
>>
>>> Hi Guys,
>>> Got a Holley 650 double-pumper on "Dad's hotrod" with some probs
>>> tuning. Upon depression of the throttle, my fuel/air ratio gauge shows
>>> that the mixture goes way lean and the engine goes into lean misfire
and
>>> dropped power. Eventually it richens back up as the RPMs slowly
>>> increase. Not talking about the accelerator pump, just giving it a
>>> little more gas while driving.
>>> Bought the carb from my machinist in the original box in like-new
>>> (visually) condition. Here's what's new and ruled out: high-volume
fuel
>>> pump, fuel filter, fuel regulator and pressure gauge, float needles &
>>> seats, jets (just to be sure), 6.5" power valve (like the original).
>>> both squirters appear to pump fine but the problem occurs when you
>>> slowly roll into the throttle and it happens really quick (very
throttle
>>> sensitive).
>>> It's a moderate, street performance SB Chevy that makes about 10.5"
>>> vacuum at idle. I know the PV should move up to 8.5" but rolling into
>>> heavy acceleration (vacuum below PV opening point) doesn't overcome
the
>>> lean condition either.
>>> Two last things are that idle mixture is pretty un-responsive to
idle
>>> mixture screws, even when idle speed is as low as the engine will
>>> reliably rev. Second, main jets were very, very rich at stock 67's
>>> (primary) and still a tad on the rich side with 65's.
>>> Dirty passage somewhere? Higher vacuum power valve needed and drill
>>> the PVCR's? I'm a little stumped.
>>> Best Regards,
>>> Drink
>>>
>>> '87 TransAm (No computer controls)
>>> Holley 650cfm double-pumper
>>> Victor Jr. single plane
>>> 186 heads, fully ****ted with 2.02 valves
>>> 218/228 roller cam
>>> 1.6 magnum rockers
>>> 10:1 KB pistons
>>> Mallory Comp9000 distributor
>>> Hooker SuperComp headers
>>> 3.73 gears
>> Maybe you aren't talking about the accelerator pump, but you should be
>> looking at it.
--
Eugene Blanchard
http://www.catsasskustoms.com
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