$400 carbureator = the root of my problems...

[Ddragggon]

paid about $450 after tax for a new, not rebuilt Edelbrock performer carbureator in november of 2002... seemed to work better than the crap I had on the 350 that used to be on the suburban. so, when I installed the 454 in my K20, imagine my utter surprise, and shocking anger at the fact my truck magicaly developed a vapor lockiung problem. so, after banging my head against everyting in sight, replaced all the filters, ran compressed air through the fuel lines, and etc, I swapped the old nasty carb back onto the suburban that was originaly on the 454.

what I've noticed in the 5 minute test drive:

-I can't get it to die on WOT like I could with the other carb
-engine runs 25 degrees cooler
-doesnt start to fade out at a stop light like the other one.
-idle wanders slightly, but it did before.
-rough transition when the secondaries open, but as before, it was like that previously.

I can only surmise that the $400 carb has something seriously wrong with it that's running the engine lean, and allowing the truck to vaporlock, and that I'm really pissed off now.

 

[chvyhs]

My brother builds carbs for a living. If you want I'll hook you up with him. I promise you won't be disappointed with his work. He's built about 6 carbs for guys in our club and you won't hear anything bad about his work or prices.

If anyone's interested let me know.

 

[y5mgisi]

Dude, you are useing a carb that was intended to be used on a 350 on a 454. Id say that would be the problem. Alean running condition creats big time heat and will not have the gas to support a fuel hungy beast like a 454. When i put a carb off a 305 on my 350 (ran awsome on the 305) it made my350 the bigest pile of junk id ever herd run. So i rejeted it using 350 specs and it ran like a dream. so id say too little CFM and to little jetting casue the crapy running situation IMHO /forums/images/graemlins/tongue.gif

 

[Ddragggon]

Not nessicarily true. The carb I bought was an edelbrock performer quadrajet. While it may have been misjetted, opening the idlescrews should have taken care of any issues with overly lean mixtures. 750 cfm is more than adequate for a 454 that's never going to break 5500 rpm... 600 would work just fine. I think its a float problem, , or a stuck rod (power piston jammed shut? ) or perhaps dirt in the bowl.... Afterall, the truck its on is 31 years old....

If it weren't my daily driver, I'd pull both carbs apart, and scavenge the rods and jets from the old 454 carb, and install them in the edelbrock carb, along with a new float, and etc.

 

[HarryH3]

[ QUOTE ]
While it may have been misjetted, opening the idlescrews should have taken care of any issues with overly lean mixtures.

[/ QUOTE ]
Adjusting the idle mixture screws will only affect the engine at or near idle. Most of the fuel comes through the primary jets while going down the road. Install the correct jets, that will flow enough fuel to feed that 454, and the engine will run WAY better. /forums/images/graemlins/thumb.gif You may also have to mess around with the metering rods to get it to run just right. They are tapered and fit into the center hole in the jets, to control fuel flow. As the throttle opening increases, the metering rods are lifted out of the jets. Different sizes, rates of taper, etc. all have an effect on how the engine runs. Perhaps a call to the Tech line at Edelbrock would net you some info to get the jet size into the ballpark for your setup. /forums/images/graemlins/cool.gif

 

[Ddragggon]

well, I had the same problem last night on the way home, and it was even cold outside...

today a thought struck me: perhaps my Fuel tank vent is plugged, and as such the tank builds up enough vacuum to make pumping fuel from it too much for the pump to keep up with at low speeds. this makes sense, as I have most of my trouble after the 5 mile uphill drive on I-15 after work, when I turn down the street to get home, and go up a 5% grade for about 500 feet or so. last night it stalled out there, and wouldn't restart for about 15 minutes or so, ( which is on par for usual) who knows though. I'm getting really tired of this damn truck pretty quickly, and it seems to be telling me it's tired of me.

todays surprise problem involved zero power getting from the battery to the ignition switch, or the rest of the harness for that matter. after 20 minutes of wiggling wires, and shaking the `Spinal column' of wires that traverse the top of the enigne, I heard the voltage regulator click, and I suddenly had power agian. this on top of a transfer case that won't stay in 2 hi, unless you hold it there) specificaly, 4 hi) and the stalling problem, is making my grandfathers offer of a new truck if I sell this one seem all that much better.... /forums/images/graemlins/frown.gif

-Rich

 

[SUBFAN]

Does the Edelbrock have a filtering screen also?

Are all the vaccuum lines pluged/installed right?

I agree with the rejetting issue, but I wouldn't think it would be that far off to run that bad. I hope you still have the tuning book that came with the carb, go through the trouble shooting steps in there.

I was trying to find pics of your rig, but the @home thingy did not work.... /forums/images/graemlins/dunno.gif

Maybe with the install of the 454, the Edelbrock sucked in a lot of crap. Was it a freshly built motor, or something you had laying around?

Maybe there was enough crap in the fuel pump/line to screw up the Edl., which is flushed out now, not effecting the old carb????

 

[Ddragggon]

I dunno, I suspect a malfunctioning float. I replaced the filter about 2 weeks before I swapped engines, and the 350 was having some issues too, granted, I attribute those mostly to the blown headgasket thing. I may pull it apart and look, but as long as my current carbureator still works, I may not bother with the edelbrock one. wait until this one starts to have issues, and leaks, then pull it appart for the jets, needles, and powers valve spring. that would get the edelbrock running the same way as the one I have on there now, and should be able to keep up with whatever I throw at it then.

I fixed the damn electrical issue... the main power butt splice along the firewall had failed, and coroded through. so, I cut the splice out, put some fork ends on the exposed wires, and put a massive terminal block on the firewall to seperate all the accessories from each other, and look cooler.

-Rich