Rebuilt my quadrajet, still runs like dookie. Possible ignition issue?

[jrblanke]

I have recently rebuilt my quadrajet on my goodwrench 350. I put it on last night, hooked everything up and I believe I set my float level too high. When I rebuild it, I seated the idle mixture screws, then turned them out 2.5 turns (Doug Rue's book). When I started the truck, it was blowing out black smoke at idle, and also when I revved the truck. It was also very sluggish when I tried to rev it. When I screwed the idle mixture screws in a full turn, it leaned it out slightly but black smoke was still visible during revs. It also did not like to rev, like it was a lot of work for it to rev up.

I drove the truck down the street and it didnt seem to have much power (less than normal).

After fixing the float level, I am going to verify that the new fuel filter is still clean. Then I am going to manually turn over the engine until cylinder 1 is at top dead center, and then I plan to verify the balancer has not slipped and the distributor is not off a tooth.

I set the timing at 4 degrees BTDC last night, but it still ran like garbage.

Can a bad float level (too high) cause the truck to not have any power?

I am kind of frustrated, and don't really know which direction to go, if you could not already tell.

[Corts60]

I would say your problem is still in the carb. If you have a vacuum gauge, use that to set your idle screws. You want to achieve the highest vacuum reading at idle. Make sure it is hooked to a manifold source and not a ported source. After those are set, leave them alone. If you still have black smoke, there's a chance that maybe a metering rod is hanging up or something. They are pretty easy to bend or damage during an overhaul. As for the stumble when you rev it, check that your air valves on the secondary are opening properly. They may be too tight and starving the carb.
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[MDc10]

I think your problem is that quadrajunk you rebuilt, I would toss it, I've never had any luck rebuilding them, now if I ever run across then they come off and go to the can.
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[Pyrotechnic]

Float level will cause the carb to flood and dump a bunch of fuel into the engine, and create the black smoke you were seeing. Definitely verify that it is correct.

[Malo83]

Originally Posted by MDc10

I think your problem is that quadrajunk you rebuilt, I would toss it, I've never had any luck rebuilding them, now if I ever run across then they come off and go to the can.
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Maybe it was operator error! my rebuilt Quadrajunk was rebuilt 10 yrs ago and it;s still running like a champ, Qjets are a good carb if you know what your doing and get them set up right

[Corts60]

Originally Posted by Malo83

Qjets are a good carb if you know what your doing and get them set up right

X2.
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[INSIDIOUS '86]

Why are you setting your timing so low? Get that thing to ten! At least.
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[bnoon]

Are the plugs looking OK, or at least even with each other? A dead cylinder will make black smoke no matter what you do to the carb or timing.

I also agree the the Quadrajet is a great street carb when rebuilt and setup properly.

[Dead Parrot]

Black smoke = too much gas. Float level too high or debris under the float needle. Did you epoxy the fuel well plugs? (pg 79-80 of Roe book). While you have the epoxy mixed up, put some on the casting plug on the filter housing.

[406 Q-ship]

Originally Posted by MDc10

I think your problem is that quadrajunk you rebuilt, I would toss it, I've never had any luck rebuilding them, now if I ever run across then they come off and go to the can.
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Spoken like someone who has no idea how to work on a QUADRAJET. The best fuel metering devise this side of fuel injection. You probably install those uncontrolled leakers from holley. I pull Holleys off and sell them to "racers" and on goes a Qjet, then the mileage and driveablity comes back.

All the morons who call them Quadrjunk, quadrabog and any other stupid name should not be touching a Quadrajet.

If your getting response out of the mixture screws while it is still that rich, that is strange. When you rebuilt the carb, how did the plugs in the bottom of the main body look? If they are leaking it can become an issue. Did the power piston move in its bore smoothly? Another place to look is how well did you blow out the air bleed passages and the you did not over tighten the air horn. Q-jets are very complicated fuel metering carbs and can be tough to rebuild at times but with time a patients you will be happy with the results.

[Oilbrnr]

Well said 406!

[MDc10]

Originally Posted by 406 Q-ship

Spoken like someone who has no idea how to work on a QUADRAJET. The best fuel metering devise this side of fuel injection. You probably install those uncontrolled leakers from holley. I pull Holleys off and sell them to "racers" and on goes a Qjet, then the mileage and driveablity comes back.

All the morons who call them Quadrjunk, quadrabog and any other stupid name should not be touching a Quadrajet.

If your getting response out of the mixture screws while it is still that rich, that is strange. When you rebuilt the carb, how did the plugs in the bottom of the main body look? If they are leaking it can become an issue. Did the power piston move in its bore smoothly? Another place to look is how well did you blow out the air bleed passages and the you did not over tighten the air horn. Q-jets are very complicated fuel metering carbs and can be tough to rebuild at times but with time a patients you will be happy with the results.

I guess nobody is entitled to there opinion anymore. Quadrajunk is my opinion, I wasn't ragging the guy for using it, I was simply saying I had no luck with it. Then you get an uneducated redneck such as your swearing by them, calling everyone who disagrees "morons". Any idiot can read how to rebuild one online. All I was telling the guy was I had no luck rebuilding one, which gave me a bad experience with them and now when I come across the they come off the vehicle. So next time before you go calling everyone morons who doesn't agree with you just remember everyone is entitled to there opinion, or at least where I come from they are. Just remember everything expressed here is my opinion and I am entitled to it.
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[Oilbrnr]

MDc10: An opinion is one thing, pure ignorance is another.

The Quad is one of the best OEM carbs of its' time. Mother GM would not have stuck with it for so many years if it wasn't. I've been from sea level to 9000+ feet with several trucks/cars equipped with them and they are stellar. When set up properly... which ain't that tough.

I think that 406 and myself get burnt out on ignorant guys coming on this forum and others bashing something that they don't understand.

BTW, ignorant is not meant to be demeaning, just a statement of fact.

[SSC's76]

everyone is entitled to an opinion just when it come to this subject people get crazy. imo edlebrock is the worst carb made. that right there can set people off but its my opinion. back to the topic sounds like the fuel level was high. its also possible the front metering needles may not be set in the slot correctly which is easy enough to tell with a small probe. alot of rebuilds I've fixed were caused by the piston stuck up cause the gasket was installed wrong or the primary or secondary lettering rods were not seated properly actually one time this guy neglected the secondary rods all together


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[MDc10]

Originally Posted by Oilbrnr

MDc10: An opinion is one thing, pure ignorance is another.

The Quad is one of the best OEM carbs of its' time. Mother GM would not have stuck with it for so many years if it wasn't. I've been from sea level to 9000+ feet with several trucks/cars equipped with them and they are stellar. When set up properly... which ain't that tough.

I think that 406 and myself get burnt out on ignorant guys coming on this forum and others bashing something that they don't understand.

BTW, ignorant is not meant to be demeaning, just a statement of fact.

once again, I wasn't bashing it I was stating my opinion and that I have had no luck with them. You said it yourself "the best of its time" which was what, the 80's? Would you say they are still the best in present day carbs? I'm sure an edelbrock or a Holley guy would disagree. As far a being ignorant your the idiot that used the word "ain't". So before you go running your head and calling everyone who don't agree with you and your "opinions" which is the key word here, names remember everyone is entitled to there opinion whether you like it or not.
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[C-10 simplex]

i would say at least try to tune the idle screws with a vacuum gauge. If no vacuum gauge (pretty cheap) then turn the screws in--both screws must generally be turned in or out the same, just until the engine stumbles a bit, then turn them out just a hair.

Then verify that the choke is working correctly.


2) While 4BTDC may seem a little tame, i would say that if the engine can idle steady at 500-600 in gear or 700 in neutral then the ignition probably ok for now and not the real probably although advancing it would probably help performance overall.

3) What are you setting the float level to?

[INSIDIOUS '86]

Not even a gm crate comes with that low of timing. That is fact. Untill his ign system is fixed any triumphs with his quadbog( call me ignorant idc junk is junk) is forfeit. If the timing is bad so is the burn if the burn is bad not all the fuel is burned and voila black smoke
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[MDc10]

Originally Posted by INSIDIOUS '86

Not even a gm crate comes with that low of timing. That is fact. Untill his ign system is fixed any triumphs with his quadbog( call me ignorant idc junk is junk) is forfeit. If the timing is bad so is the burn if the burn is bad not all the fuel is burned and voila black smoke
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Thank you. These guys get all uptight for giving your opinion. Glad to see other people feel the same way I do. You are correct "junk is junk".
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[Oilbrnr]

Originally Posted by MDc10

once again, I wasn't bashing it I was stating my opinion and that I have had no luck with them. You said it yourself "the best of its time" which was what, the 80's? Would you say they are still the best in present day carbs? I'm sure an edelbrock or a Holley guy would disagree. As far a being ignorant your the idiot that used the word "ain't". So before you go running your head and calling everyone who don't agree with you and your "opinions" which is the key word here, names remember everyone is entitled to there opinion whether you like it or not.
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I stand corrected. Sorry for doubting your infinite Quadrajet knowledge. I'm humbled...

[Corts60]

Alright guys, let's save the pissing match for another thread, eh? Arguing back and forth is not helping the original poster solve his problem, which is what we are here for, to help solve problems. He was not asking for opinions, he was asking for advice and that is all we need to give him.

Jrblanke- have you come any further with your issue?
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[jrblanke]

Thanks for the responses guys. I have not had a chance to update this thread.

I have had success in the past with q-jets and have spent about 90 bucks on books/filter/float/plastic cam/etc, so I am going to try to get it to work correctly.

As far as the truck goes,I took today and tomorrow off to work on the truck. I took the top of the carb off and adjusted the float level and verified the fuel filter was clean. I have not started the truck and driven it yet because I got distracted sealing up an exhaust leak.

I was going to start it today but did a stupid/dangerous move and forgot to hook the fuel line up. The truck has been sitting for a couple days so nothing was hot, but it still blew gas all over the top of the engine. I left the fuel line off the other night when I was called inside by the wife to tend to something else. I forgot to check the engine compartment before trying to start the truck. At least the fuel pump works, right?

I need to purchase a vacuum gage in order to set the idle mixture screws correctly. Any suggestions on where to get that?

[INSIDIOUS '86]

Originally Posted by Corts60

Alright guys, let's save the pissing match for another thread, eh? Arguing back and forth is not helping the original poster solve his problem, which is what we are here for, to help solve problems. He was not asking for opinions, he was asking for advice and that is all we need to give him.

Jrblanke- have you come any further with your issue?
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Correct this isn't the hottoddlers forum after all or yellowtrollit forum
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[GM-power]

Originally Posted by INSIDIOUS '86

Correct this isn't the hottoddlers forum after all or yellowtrollit forum
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Nor is it a f#!d forum!
Kidding aside q-jets are great if you can tune them right. Im happy with mine.
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[superwade57]

Originally Posted by MDc10

I guess nobody is entitled to there opinion anymore. Quadrajunk is my opinion, I wasn't ragging the guy for using it, I was simply saying I had no luck with it. Then you get an uneducated redneck such as your swearing by them, calling everyone who disagrees "morons". Any idiot can read how to rebuild one online. All I was telling the guy was I had no luck rebuilding one, which gave me a bad experience with them and now when I come across the they come off the vehicle. So next time before you go calling everyone morons who doesn't agree with you just remember everyone is entitled to there opinion, or at least where I come from they are. Just remember everything expressed here is my opinion and I am entitled to it.
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thing is just as you are entitled to your opinion so is he. whether it be about a carb or about someones opinion, hes just sharing his knowledge to help avoid people throwing away a great carb because their buddy said they were junk, if that stuff happens to long he'll end up paying bookoo bucks because of a limited supply of something that was once plentiful. not to mention imo id have to agree.. ive always heard quadrajunk, and ignorantly repeated it until someone told when set up properly they are great. so i researched, and although im afraid to rebuild one, because they are one of the most complicated designs ever, id like to find someone knowlegable to rebuild mine. think about the design... you have 750-800cfm(i believe) at your pedals desire if you ever need it, while at the same you have no fear of over-carbing even the weakest v8. drivability, versatility, and unless youre pro racing in most cases youll raceability and for sure all the response and fuel you need for a thorough friday night beating.

[85Bowtie]

Your timing is way off, try setting it at 6 deg and see if that makes somewhat of an improvement. You also need a vacuum gauge to hook up to the manifold port and see exactly what's happening when you turn the mixture screws in and out. Setting the float too high can cause it to bog....it sounds like you have several issues going on.

Personally, I would ditch the Quadrajunk as well. I've heard how great they can be when set up properly, etc. But to me, a carb that requires epoxy to be rebuilt "properly" is a piece of junk. The carb is more complicated than it needs to be, especially when there are other carbs out there, like Carter, that work just as well in stock form. The trade off just isn't there in my opinion. I wouldn't say Edelbrocks are "the worst carbs ever made", they've always worked great for me on stockish engines. You might one to pick up a 1406 and try tinkering with that if in the end it turns out the Qjet is junk, and I'm guessing it is. If they are as great as people say they are......try selling one....

Good luck