bunkie21

Ok heres the deal. I have an LG4 with full exhaust, performer intake and a standard HEI. I installed an Edelbrock 1406 600cfm carb in place of a poorly operating non-cc quadrajet that had no choke.

The problem is that from idle - 2000k rpm seems like a total dog and seems to have some sort of hesitation or maybe even a bog. Its hard to describe but feels something like the ignition is not working properly but after 2K that car runs and runs good. Since I have 2.73's I spend most of my time below 2K so its starting to get on my nerves.

Does anyone have any clues as to where I should look? I have no experience with Edelbrock carbs so I'm at a loss. Also I have played around with the timing alot so I dont think thats the problem.

89RS_82Z

iTrader: (2)

did you replace the dizzy with a vac advance one or leave the stocker on, wait never mind you had a non cc qudra

it needs adjusting, but without being there i cant really tell you what way to go

lasher_350

What did you do for the choke on the Edelbrock? Also, which vaccum are you tapping into for the advance on the distributor, the manifold vaccuum port or the venturi port?

bunkie21

The HEI is fairly new and is a Jegs brand, nice unit for the price.

As for the choke I spliced the original choke wire that was used for the original CC quadrajet. And I currently have the vacume advance on the ported vacume. I tried it on the other and didn’t notice much of a difference.

89RS_82Z, are you saying that you think the carb needs adjusting? Someone suggested that I put a lighter spring on something in the carb, I would have to look at the email to tell you exactly what they recommended.

* Edit - I have also noticed that when I first start it in the morning it jumps up to 2000 rpm, I tap the throttle and it goes down to 1100 or so and stays there until I put it in gear or it warms up.

Street Lethal

iTrader: (16)

Are you running off of the primaries, or the secondaries though? Meaning, are you babying it to 2000-RPM, or are you at wide open throttle from the get-go? Assuming your at WOT, it sounds like you need to adjust your secondaries. If it's bogging, they're opening too soon. If the engine feels like it's holding back, they're opening too late....

blue85305

if you're not a wot, then you need to adjust the idle mixture, because when you're at a cruise/light throttle application, then thats what you're running off of. I think its been covered on here, if you can't find it, i know car craft showed how to do it in last months issue, so you should be able to find it on they're website.

bunkie21

It’s specifically at light throttle. So the idle mixture (the two "screws") affect light throttle and could be causing the stumble. I will check and see if I can find the info on the board but does anyone know what a safe starting point is? I don’t know where they are at now but will check it.

Street Lethal

iTrader: (16)

Lean out both mixture screws (clockwise), but don't bottom them out too hard. When both are closed, richen them (counter clockwise) 1 1/2 turns out each. It's best to set them with a vacuum gauge hooked to a manifold vacuum source....

bunkie21

And I set them for the highest vacuum, right? Do they need to be set the same or just max vacuum?

Street Lethal

iTrader: (16)

You'll want to meter them as close as possible, so fatten one mixture screw until the vacuum gauge increases in inches to it's highest point, and no further (count the turns), then immediately bring the other mixture screw to the same exact point. Lower the fast idle screw back down to a reasonable RPM, then repeat the process all over again until the gauge can go no higher. You'll want to do this in gear, so make sure the e-brake is up....

bunkie21

Great! I will let you know how it goes. Thanks for everyones help.

kennn

I assume this applies to LG4 auto only, not manual.

blue85305

correct assumption

bunkie21

Ok, I followed the above advice and I think that it fixed my problem. I havent driven too many miles yet but I think its fixed. Thanks for the info and help!

Street Lethal

iTrader: (16)

Of course it does, just leave it in neutral with a manual....