I said I was going to TBI this thing - and I'm still way open to the idea. Still, I want the satisfaction of having it run at least decently for now, hence, the following Edelbrock 1406 hijinks:
As I mentioned before, the next issue on the agenda (which I didn't particularly explain coherently in the previous post) is that the 1406 has an off-idle bog - and I don't mean the slight delay if someone punches it like a maniac to WOT, I mean a
massive bog (causing a fair amount of rough vibration) on the
lightest of acceleration off the idle circuit. I'm talking about rolling into the pedal as if it was ready to bite off the toe of your Oxfords. Continuing to pull the throttle open results in the bog followed immediately by an unnerving surge of acceleration, as the carb unevenly transitions off the idle circuit to the main jets.
I've been through this before, involving least one prior carb cleaning where I spotted air bleeds in the primary venturis full of enough junk that one couldn't see through them. But since I cleaned everything that time...were those air bleeds
specifically the culprit?
This time, I decided to be a bit more precise about establishing this data point. I pulled the main venturis, and the main venturis only. A familiar sight awaited:
Sure, you can see through the idle air bleed, but how about the high speed air bleed? Clogged solid.
I also looked at the idle by-pass air bleed, which I'd
assume is the actual circuit being used as the car comes off idle, but even though this is a 90% bleed (and thus I can't verify by just looking for light coming through it), it didn't appear plugged.
Also note the fuel stains around the passenger side high speed air bleed. I'm not sure fuel is supposed to wind up here in the first place. Could boiling fuel be oozing up to this level? Either way, it seems to be making it up here somehow.
Whatever the case, there was nothing getting through it, not even carb spray. Had to pick it with a thin wire, then spray it.
I'm putting this shop reference here so anyone who doesn't know what I'm talking about can refer to the diagram. No, I'm not necessarily advocating for drilling the idle feed restriction holes, as this edited image suggests:
At any rate, even though I cleaned these areas out quite well, I decided to be absolutely sure by dumping both venturis in some carb cleaner before returning them to the 1406.
Meanwhile, while I had the choke horn off...
See it? One of the plastic tabs holding the accelerator pump seal has broken off.
I went ahead and ordered a replacement, which is also when I learned Edelbrock now has an "ethanol-resistant" version (#1470) that's in the typical Viton blue. I bought this carb five or six years ago; shouldn't it have already come with ethanol resistant everything?
What really gets me is how bad Edlebrock is at making
anything clear about the parts that are E10/gasohol compliant, and when they do exist, they're barely obvious. Case in point, this thing is listed primarily as an AVS part, but Edelbrock seems dead set on avoiding the historical acronym for the AFB. For this part, they referring to it as the EPS (Edelbrock Performer Series):
"Edelbrock carburetor Accelerator Pump Assembly with Viton cup for 1400, 1403, 1404, 1405, 1406 EPS Carbs as well as 1801, 1802, 1803, 1804, 1805, 1806, 1825 and 1826 Thunder Series AVS carbs."
Really? Choose a naming convention, Edelbrock. Either it's the AFB & AVS or it's the EPS & ETS. SOGOTP already.
Given the number of threads I've been over the last two days, my brain is too frazzled to untangle advertising hieroglyphics hijacking well-established names.
That's not the end of my rant though: I find it nuts that there's no clear resources online - whether on other forums, the H.A.M.B. (which is not just any other forum, IMO - if the answer isn't here, it's nowhere), or any other source - that really discusses, indicates, or otherwise establishes whether Edelbrock's
own gasket kits are E10/gasohol compatible.
You can't even get a straight answer for the blue non-stick kits, which you'd
assume are Viton, but nobody seems willing to advertise them as such, and they only seem to be for the choke horn. I'm not about to take the leap that it's not just blue Chinesium, as these aren't official Edelbrock products (they may be Walker, but not 100% sure), and I don't want a surprise fire under the hood.
Pic off an eBay listing that claims this is a Walker kit:
So where was I? Oh yes, cleaning out the idle and high speed air bleeds. I did that, cleaned
nothing else, and reassembled the carb as-is, including the now three-legged accelerator pump seal.
Problem solved. No bog on initial acceleration, happy idle, and not a problem in sight. This proves my theory that at least one of these bleeds clogging up creates a world of pain for normal operation. But
which bleed is it? I suspect the high-speed air bleed by virtue of the fact that it's the one I can visually confirm gets entirely plugged, but I don't know enough about the Edelbrock's off-idle operation to know how they factor in (if at all) when transitioning off the idle circuit.
Equally perplexing to me is why on earth these bleeds clog so bad after a month's time of sitting, usually after the shortest of neighborhood test drives. The stains on the venturi assembly point to fuel varnish rather than any foreign deposits creating the clog, which goes right back to the question I posed earlier: Why should fuel even get to this air bleed?
-Kurt