Quadrajet RPM HELP!!!!!

g0thiac

G-Body Guru
Sep 6, 2020
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That vacuum leak for a hot air choke ain’t nothing to worry with. It is designed to leak pulling in air from the back of the carb and through the heat tubes into the choke housing. But if it’s bugging you a drip of solder or rtv and plug it. It would get dirt in there the way it is now so if it is a hot air choke that would be bad. But weren’t most mid 80s Chevy carbs electric choke?

Of course you will want to plug that big hole the choke shaft goes through as even with the air cleaner on tha hole will suck in dirty air.

Since you removed the choke stuff there’s no fast idle setting to worry about so that ain’t it.

Is this a CCC carb or no? It sounds like a no because of tweaking with everything.

First off, stop.

If the carb was working on your ponti just fine, but the original carb on the Olds was acting up and now the ponti carb is acting up, the common denominator seems to be your Olds 305. Correct me if I’m wrong here.

How are the carb and intake gaskets? EGR stuff? Anything leaking air where it shouldn’t? Power brake line snug?

Take the time and rebuild that Olds carb and put everything back to factory specs then go from there.

That’s where I’d start.
The carb off the Pontiac worked fine, when I put it on earlier this morning. The choke was not working, as the electric part was broken- and I couldn't kick down the idle, obviously so it stuck at a higher speed.

But not the high RPM like afterwards, all I did was drive it for less than 1 minute, realized in gear it still was too fast, so I shut it off, adjusted both screws.

Then, when I turned it back on thats when everything became an issue. That said, yeah I am going to rebuild both my Olds carbs since they were before anyway.

I will post back with results tomm, and try a few more things.
 

79 USA 1

Royal Smart Person
Sep 2, 2011
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Cheektowaga, New York
If the choke housing was removed, even an electric housing has a plug installed to prevent a vacuum leak. Part #362 in the diagram below is the plastic plug used with a electric conversion from hot air. In your photo that is a wide open vacuum leak.
A smear of silicone sealer or even JB weld (If you never plan to install the choke housing) should work to seal that port.
Just my $.02.

qjet_choke_nib2.jpg
 
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g0thiac

G-Body Guru
Sep 6, 2020
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If the choke housing was removed, even an electric housing has a plug installed to prevent a vacuum leak. Part #362 in the diagram below is the plastic plug used with a electric conversion from hot air. In your photo that is a wide open vacuum leak.
A smear of silicone sealer or even JB weld (If you never plan to install the choke housing) should work to seal that port.
Just my $.02.

View attachment 220271
This stupid motherf'king choke agh! I just knew I messed up, and had a vacuum leak.

Like pretty worn just even the start I am having man, because in 48 hours I went from having 2 bad distributor caps, my old carburetor leaking and now a huge vacuum leak, which may have caused damage, from the RPM's hit.

Ok. Thank you so much, I learned my lessons with the choke on a Quadrajet. Almost 10, here and I literally am still covered in mud and dirt, from trying to just get the hood open earlier from under the vehicle, all the rain today had me swearing beyond comprehension
😥😭😭😭

So I'll just reinstall the housing. Since I took the choke rod out, no point trying to hook up the secondaries I guess?
 

79 USA 1

Royal Smart Person
Sep 2, 2011
1,062
2,033
113
Cheektowaga, New York
This stupid motherf'king choke agh! I just knew I messed up, and had a vacuum leak.

Like pretty worn just even the start I am having man, because in 48 hours I went from having 2 bad distributor caps, my old carburetor leaking and now a huge vacuum leak, which may have caused damage, from the RPM's hit.

Ok. Thank you so much, I learned my lessons with the choke on a Quadrajet. Almost 10, here and I literally am still covered in mud and dirt, from trying to just get the hood open earlier from under the vehicle, all the rain today had me swearing beyond comprehension
😥😭😭😭

So I'll just reinstall the housing. Since I took the choke rod out, no point trying to hook up the secondaries I guess?


I'm just outside Buffalo NY, we've had over 4 straight days of "Liquid Sunshine" so I get the frustration. As far as the choke housing I would re install it or just plug the hole that part #362 installs into. (Red Arrow) While you are there also remove the lock out lever that contacts the roll pin on the secondary throttle shaft. (Pen Point) I've done this to every Q Jet I have to allow the secondary throttle plates to respond even with the choke activated.
Secondary_Throttle_Lockout_Lever (2).jpg
 
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Oct 14, 2008
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Glad you found it. You want a working choke on your carb. The non CCC Canadian Qjets are calibrated extremely lean. It will start and run like sh*t when cold without one. Buy a quality kit and new float. Check for play in the throttle plates, probably worn.
 
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Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
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Galaxy far far away
If the choke housing was removed, even an electric housing has a plug installed to prevent a vacuum leak. Part #362 in the diagram below is the plastic plug used with a electric conversion from hot air. In your photo that is a wide open vacuum leak.
A smear of silicone sealer or even JB weld (If you never plan to install the choke housing) should work to seal that port.
Just my $.02.

View attachment 220271

I just checked my spare E4ME carbs which use E chokes and they do not seem to have the vacuum passageway drilled all the way though to even require a plug. The hole appears to only be drilled deep enough for a rivet on E choke models.
 
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g0thiac

G-Body Guru
Sep 6, 2020
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I just checked my spare E4ME carbs which use E chokes and they do not seem to have the vacuum passageway drilled all the way though to even require a plug. The hole appears to only be drilled deep enough for a rivet on E choke models.
Maybe the carb, that someone put on the Pontiac years ago, was converted from hot air.

Because there definitely was a vacuum leak, plugged that hole up, changed the curb idle screw and it runs and moves again- well other than the occasional backfiring from both the mixture screws, needing adjustment 😎😭


Next up, oil change, coolant change, spark plugs & wires lol.
 
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Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
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Galaxy far far away
Maybe the carb, that someone put on the Pontiac years ago, was converted from hot air.

Because there definitely was a vacuum leak, plugged that hole up, changed the curb idle screw and it runs and moves again- well other than the occasional backfiring from both the mixture screws, needing adjustment 😎😭


Next up, oil change, coolant change, spark plugs & wires lol.

Well its certainly something to check for with working on Qjets. Especially with choke conversions. You never know what parts got switched which way.
 
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g0thiac

G-Body Guru
Sep 6, 2020
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Well, bad news is guys, I leak oil now because I forgot to unplug one of the capped lines, going to my PCV valve, so I think the rear main seal I think is ****ing shot 😞👌👌👌

Good news is, after the big puddle of oil was cleaned, and I changed it since the old stuff was from 2017 when the vehicle was last driving, this 305 doesn't feel like one at all.

It feels bigger than that. However aside from the remanufactured carb, that was on it before- I don't see any signs of an engine swap haha. Like I spent some time, with the carburetor tuning bits on a screwdriver, as it needed to be more richened up- and WHOA!

It's really have me glad, I bought the tools to adjust those studs, adjusting the rochester makes me think, the guy at the part store jokingly labelled it the quadrabog?

He doesn't get the power of these things. Like I sure as sh*t didn't.

But I still need a vacuum gauge, and see what I am doing- otherwise yeah, hopefully I didn't damage another motor, will keep an eye on the oil level, and correctly tune both screws.
 

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