quadrajet secondary adjustment

[bedwards]

THanks guys. I ordered the EGR tonight and have the carb kit already. It will be this weekend before I build the carb. I will give you an update.

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Got the EGR on but figured I'm this far might as well look at the carb. It was a little dirty inside from 3 years use but it wasn't that bad. No water in it. But there was a vent tube laying in one of the wells for the secondaries. I tapped it back in place and staked both of the tubes so maybe they won't move again. I also popped the plug out above the adjustment for intermediate throttle and tapped it for a large set screw so I can take it out and adjust the mid throttle if need be. Its all back together but not on the truck yet. Will put it on in the morning and let you guys know how it is doing.

thanks again for all the ideas and help!

[JohnnyPopper]

Ahhh the errant vent tube...Probably just solved your problem. Tune up of carb settings  will be a bonus.

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ok,, at a loss, no joy. Exactly the same behavior.....

[blazer74]

Does it recover from the bog after the flat spot?
Does it stumble? Did you check the pull-off for a vac leak? Don’t start messing with the apt. Been working fine till recent, that’s a set adjustment.
Just a note if you hold the throttle open in neutral long enough to have the secondaries open, don’t do that.

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Rebuilt carb Friday night. Same behavior, cranks, idles and pulls really good up to when the secondaries come in. Then it just bogs down. As soon as you let up on the throttle its fine. I did adjust the APT. I knocked the plug out, tapped and put a big set screw in it so I could adjust it. It was a tad rich but is very smooth now transitioning from one circuit to the other. I have adjusted the spring on the secondary plates from factory tighter as much as 1/2 turn in 1/8 increments and adjusted lighter the same. It wants to pop up the carb if too light and bog if too tight but I can't seem to get the bog out of it.
I have been all over the top of the engine. There are no vacuum leaks. The vacuum timing is working, visually saw it, set it on 4btc although I did have it on 8btc. The secondary vacuum is working. The EGR is working now, put a new one on. At the risk of sounding like a parts replacer, I doubt its ignition with new cap, coil, module, plugs. The wires are 3 years old but its not missing. Just a bog like its too lean. The plugs I took out weren't
that old. The engine used to run rich and it showed on the plugs but now its dead on to maybe a little lean. I can send plug pics but I don't think that's it. I'm going to get a vacuum gauge and see what it tells me this week. I'm not sure which port to use for it unless just one of the base ports.
I don't think its a cam, wouldn't be running bad at lower or missing rpm for a bad cam? There is no missing. Smooth as silk.

[Irish_Alley]

i can say this, my mud truck would bog if i floored it, if i i got into it slowly it was ok. after just dealing with it and a few years later after finding more about timing i set base to 16° so my total was around 32 or so and hooked the vacuum advance to manifold vacuum. totally different engine. i cant remember if i messed with the carb screws any but want to say i had to tune it in a little

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I was running 8btdc but was getting a little ping at tip in, but its not much difference at 4 so I'm probably going to put it back on 8.

[Irish_Alley]

if your getting ping at 8 something isnt right. has your motor been worked on? (i.e head/block work)

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I'm about one more day away from getting tired of this and ordering an Edelbrock or Holley. I don't want to spend the money and keep the truck bone stock but I am real tired of the quad. I've built and tuned a lot of carbs but this one takes the cake.
Leaning towards an Edelbrock 1400, good price, made for egr, vacuum secondaries, elec. choke and similar gas hookup. Will need an adapter from square to spread bore intake.
Any suggestions?

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no Irish, its bone unmolested stock with a little over 40000 miles

[Irish_Alley]

is your egr hooked up?
what plugs you have?

[blazer74]

Which tube fell out small or large. Large is your POE, if driven in too far will block passage to 2ndary feed hole just above air valve plates on the air horn and draws fuel when they start to open to prevent a lean surge. (Pull over enrichment)

[bedwards]

egr is hooked up just put new one on as I found old one was not holding vacuum, I was running Ac Delco 44ts I think. I was one range cooler than the book called for to try to minimize pre-ignition. I put new Accel 0566-4 in it Sat. I was grasping for straws hoping it had a bad plug. Its not missing though.
The tube that fell out was on one side of the secondaries, the larger diameter tube, thinking it was a vent tube? THere is a longer tube with a much smaller orifice on each side also. I put it back Friday night and staked both in place so it won't fall out again.

[Irish_Alley]

have you tried high octane fuel?
whats your engine temp at?
the eld 1400 is a 600cfm carb. thats too much for a 305 you need a 450-500 carb unless youre turning over 6k rpms. imo i either try to go with holley or quad. i dont know if your carb is bad or not. if its rebuilt then it should be ok. i would try to eliminate as much crap off your truck as you can as far as emissions. the ping as you know is either from high combustion chamber temps (wrong plugs or overheating) lean fuel condition, wrong octane or timing too far advance. i would try to tune the carb to its base settings, advance the timing as far as it can go (but i wouldnt be below 12).