Yo guys, need advice again. My Buick Electra 225 Custom 1974 with a 455 is acting up. It has a brand new edelbrock 1407 carb (tuned one step higher, to number 3 on the tuning chart), brand new mechanic fuel pump, starter, changed oil and filter a couple of weeks ago and new sparkplugs. When im in slow trafic in DRIVE and going forward really slow, with very little gas or just letting the car move forward by its own, the car stumbles and stalls sometimes. Not sure if it stalls easier if I apply the brakes. It has a bit of a rough idle in PARK too to be honest. I cannot find any vacuum leaks in the engine compartment. Need advice what to check next?
I'd keep looking for vacuum leaks, especially around the carb base gasket. What adapter did you use to put a squarebore carb onto a spreadbore intake manifold? Did you use gaskets above and below? -Bob C.
I think I used THIS ONE with the gaskets that came with. I cannot find any leak around the carb. Is there a vacuum-hose going down to the transmission that may be dried up and leaking? I haven't noticed any, but then again, I have not been looking for one.
Yes, there is a vacuum modulator line that comes off the back of the intake manifold and goes down to the transmission. You also have vacuum lines for PCV, power brakes, distributor vacuum advance, vacuum line for climate control, and possibly other things. If the engine is stock, it should make between 18" and 20" of vacuum idling in Park/Neutral fully warmed up. Put a gauge on it, vacuum gauges are cheap. IMO, you made a mistake buying the Edelbrock carburetor, the Quadrajet would have run better.
Engine is stock. Will check the modulator hose. PCV hose was not leaking when I looked. But maybe the PCV valve grommet is bad? Will check that too next time im by the car. Power brakes and dist hoses are fine. Not sure about the climate control hose though, what is that connected to? I'll get a gauge and check that too. About the carb choice, I think it is really all about preference and experience. My experience with Quadrajets has been... really bad, parts missing and rough idle on every one. I have always had a better/easier time with Edelbrocks. p But I also do not doubt I could get it rocking even better with a rebuilt and perfectly tuned Quad. I actually have two quads laying around that I plan to rebuild some day. Maybe then I will learn how to use them properly. :laugh:
PCV grommet would not produce an engine vacuum leak just a crank case air leak, but that would not produce the symptoms you are experiencing. The climate control doors need vacuum to operate. There should be a vacuum storage tank on the fire wall that gets it's vacuum form the carburetor. On the Q-jet, it comes off a fitting on the back of the base plate. Don't know where you put it on the Edelbrock:grin: If you left it off, the climate control doors would not work correctly. Most off the shelf Holley and Edelbrock carburetors have a generic tune that will work on any engine but they are far from optimal, they need tuning. I have no idea what #3 on the tuning chart is Most people have problems with Q-jets because the think that they are all the same, so they install a Q-jet from another year and make and expect it to run well. The Q-jet is the exact opposite of your cookie cutter Holley and Edlbrock generic carburetor. It is carefully calibrated for the exact engine it came off of, and putting it on a different year engine usually doesn't work well. It's not just a matter of jetting, it has to do with idle system size/calibration, air bleeds and other things. There are 2 guys on V8 who will custom build a Quadrajet for your engine, and I believe it will out perform the Edelbrock you have now. As you can tell, I don't like the Edelbrock AFB clones. They have a counter weighted secondary air valve that cannot be adjusted (at least easily). The AVS models at least have an adjustable air valve like a Q-jet.
Take Larry's advice, it's the best. I have been down this road with an eddy on my 350 and went with a Quad purchased and built by a member of this forum, what a difference! The Quad really does perform much better when built for your application.
I cannot find any vacuum leaks anywhere at least. Been spraying all over the engine and trans modulator. And I cannot find any hoses that goes to the climate control, most vacuum lines end in a reservoir. Though I noticed when I spray motor starter gas right down the carb, the engine rpm actually slows down and almost dies. I expected the opposite reaction. Does that mean anything? Haven't gotten around to doing an ignition timing check and vacuum check yet though. Will probably have time next weekend to do that.
Took some photos of my carb setup if you wanna take a look. Does it look correct from what you can see? Oh, also.. I measured with a vacuum gauge. It gives me 15hg on idle.
I'm with Larry; dump the Edelberg. GM cars were made to run on a GM carb not some dodge job. Theres an LOL in there somewhere... Do yerself a favor and get rid of the plastic fuel filter on the high pressure side of the pump; that's bad. ws
There is a 2 port intake vacuum fitting just to the right of the thermostat housing in front of the carb which I circled. This may need to be plugged, not sure if that's the problem, but I'm sure Larry or someone will clarify.
That's a thermo-vacuum switch, it does nothing when a vacuum source is not supplied, most people by pass them anyway. looks like all 3 of the ports have nothing connected to them.
The other thing with an Edelbrock or AFB is that it doesn't supply the air that the engine needs. That engine was designed to breathe, and not be choked off. At low RPM it doesn't need much, and at higher RPM it wants to fly. It needs a very specific amount of fuel to run at idle, and in order to overcome the deficiencies at the high end, the AFB tends to use more fuel and run rich at the low end. I think most AFB designes or derivatives top out at 750 CFM, whereas the stock Q-jet on your motor was good for at least 850CFM. AFB's are not a great carb; yes, it's a lot easier to fool around with than a Q-Jet. But the Q-jets of that vintage were just about bulletproof and they ran beautifully, and if you remember correctly, a GM product with a Q-jet generally ran better and smoother than anyone else's 4 bbl set up. I've struggled with enough Holleys, Thermoquads, and Fomoco designs to know. Find a half decent Q-jet; - give that Edelbrock to someone looking to beef up a Nova or something; those things were just not designed to be on a Buick big block. I had issues with a very early 1966 Q-jet on my car; - but I wouldn't hesitate to use a later one once I find a half decent 1967 cast. And no, they aren't that difficult to rebuild; - in fact they're easier than a Holley. In lieu of that, you may have to put on an idle compensator dashpot, that will knock the idle up when it's in gear. If your car had A/c it originally was on there, and there would have been a wire going to it. It would automatically click the plunger out sending the idle speed up.
Alright, alright, enough, I get it lol, the Eddy is all I have to work with right now so bear with me. I will get my quad rebuilt as soon as I can. Why remove the filter? I thought it was bad to let possible crap from the fuel tank go in the carb. It is? How should I place it? Yeah, the quadrajet had one of those on it I think. So.. you all think I should just leave the car be until I get my quadrajet rebuilt?
Do yerself a favor and get rid of the plastic fuel filter on the high pressure side of the pump; that's bad. ws Why remove the filter? I thought it was bad to let possible crap from the fuel tank go in the carb. Those filters are hunky dory on lawn mowers, and if you really feel the need to use it, put it on the inlet side of the pump. That plastic tends to get BRITTLE with heat/vibration/ozone or whatever. That will also protect the pump, AND keep 8 PSI of gasoline from spraying all over the top of a hot / running motor. If you still feel the need to use one in that position, get a steel unit and use the correct fuel rated (ethanol?) hose and clamps. I also carry a 3lb fire extinguisher on the back seat; beats having to drink a beer and wait to make wee-wee to put it out. Just a thought from the SAE. ws
Been doing some quadrajet research. I have now identified the carb that was on the Buick when I bought it. A Quadrajet with the number 17082224, and it seems to be coming from a 80s chevy van with a 283.. Wonderful. Too small for a 455 or am I wrong? The other old carb I had stowed away deep in my storage that was on my chevy is a Quadrajet 7045228, also from a chevy van, late 70s. Also too small I guess. Right now I feel I might be better off buying a new right sized Quadrajet from ebay or so..
Yes, 455 needs more air especially at idle. The idle system is way different on a big block carburetor. Both those carburetors are emissions carburetors to boot. Probably everything is wrong on those carburetors. We have 2 guys right here on V8 who build Q-jets. Either one can build you a carburetor. You have Ken (techg8) in Connecticut, and Mark (carmantx) in Texas. Who is closer? You haven't listed your location in your profile.
