Carb calibration, plug gap, timing??
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Joined: Jan 2010
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From: Great Falls Mt
Carb calibration, plug gap, timing??
I have a 93 351w converted to a 4bbl, and all the emissions are gone. I put an edelbrock 1406 on it in place of an oversized holley that came on it. The truck has always run rich. VERY rich. Blows alot of black, smells like gas, fouls plugs. Ignitions is good, brand new procomp set up. Fuel pressure is at 6 psi. Timing is set at 12 degrees. Plug gap is whatever stock setting would be for a 93 351 motor, motorcraft plugs. 8mm Accel wires. Im pretty positive its either timing, plug gap or the carb. After messing with it the other day I forgot to plug a vacuum line back into the manifold and ever since it has run like a scalded dog. Ive never had so much power out of it, but it still runs a little rich. Why would a vacuum leak cause an increase in performance?! How do I lean this pig out! (p.s. the carb is factory edelbrock calibration and I drive at 5500 to 6500 elevation....ive ordered the calibration kit to see if that helps)
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Joined: Apr 2004
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You are running rich, and the vacuum leak helps lean it out.
Get the calibration kit and fiddle with it to lean it out to the proper a/f ratio for your altitude.
Does this carb use metering rods or jets or both?
Get the calibration kit and fiddle with it to lean it out to the proper a/f ratio for your altitude.
Does this carb use metering rods or jets or both?
Lead Driver
Joined: Sep 2003
Posts: 7,018
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From: SoCal
I'm not familiar with the Edelbrock carbs, but I don't suppose they have something like a power valve, or anything that can blow up like on a Holley carb? I had a fuel leak through bad gasket on the power valve when I first got one of my engines together, and it ran pig rich as well. It got better at part throttle as there was less vacuum in the manifold to suck raw fuel in, and it also ran better with the vacuum leak as that was letting in more air. So this may be too obvious, but are you sure you don't have a fuel leak?
New User
Joined: Aug 2004
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well if you ordered the calibration kit then that may hold the answer to your richness problem. dumb question but how many turns out are your idle mix screws. i have the same carb on a 289 and mine are set at 2 turns out.
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From: Great Falls Mt
I set my idle screws just like they say to do on the Edelbrock video that came with the carb. I set them for lean. Ill count how many turns tonight and play with that too. This carb does have both metering rods and jets. Fuel system is brand new from take, through 2 filters, one high perf pump and to the carb. Ill double check for leaks tho.
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Senior User
Joined: Jan 2010
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From: Great Falls Mt
I got the kit and have been messing with the carb. I really like how easy it is to change the rods and jets in these edelbrocks. Also cleaned and gapped my plugs out from 48 to 53. I ended up going 6%lean in cruise mode and 12% lean in power mode with no pinging or jerking or otherwise acting up. It actualy runs great and smells much better! I need to order secondary jets for it too and go leaner as it lugs pretty hard still at wide open throttle. I dont floor her that often, so for now its perfect.
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