Stalls when pressing gas too fast

[Chevyguy]

I know how to remove it. I wanted to know if I could do it without removing the air cleaner. I am just starting out working on my truck though and trying to learn so I'm not going to know everything right away.

Anyway. I got the 5/8" and 1" wrench around the two nuts. I am trying to loosen the smaller one but it will not come loose. It almost looks like the threads are backed out a bit. If I turn the wrench with a lot of Force it moves slightly but then bounces back towards me. Almost feels like it's on a spring. But it will not come loose.

You must be registered for see images attach

You must be registered for see images

Sent from my SM-G950U using Tapatalk

Just so you can get familiar with your truck I suggest that you get a repair manual for it. I like Haynes repair manuals. Factory manuals are great too.

Clayton

Sent from my LM-V350 using Tapatalk

 

[Chevyguy]

I haven't done the fuel pressure test, but I had a friend come and take a look. He reckons it's my accelerator pump. He had a look inside the carb while it was running and pumped the throttle and didn't see the accelerator pump spray. Tried the same while it was turned off. So I have a feeling my best shot is to rebuild it or find a cheap used one. If I give the scrapyard a good long look I might be able to find a nice rebuilt carb and they only charge 30 bucks.

I have a retired mechanic visiting in a few days as well, so he might be able to help me if I decide to rebuild it.

What rebuild kits are out there that are decent for the quadrajet? I have no idea how much they cost, but it may be a good opportunity to learn to rebuild a carb.

Sent from my SM-G950U using Tapatalk

Don't buy a used carb. Rebuild yours. Get a rebuild kit from NAPA. have your throttle plate rebushed if things are loose. Hopefully your mechanic buddy can help you.

Clayton

Sent from my LM-V350 using Tapatalk

 

[Backfoot100]

Give Cliff Ruggles a call.
cliffshighperformance.com

Make sure you have the number from the carb. He'll get you squared away. Wouldn't hurt to buy abd read his book either. You'll be amazed what you'll learn.

 

[73c20jim]

Just so you can get familiar with your truck I suggest that you get a repair manual for it. I like Haynes repair manuals. Factory manuals are great too.

Clayton

Sent from my LM-V350 using Tapatalk

Check this out. Factory service manuals.

https://www.gmsquarebody.com/threads/1973-1991-service-manuals.14499/

 

[thecantaloupeman]

Don't buy a used carb. Rebuild yours. Get a rebuild kit from NAPA. have your throttle plate rebushed if things are loose. Hopefully your mechanic buddy can help you.

Clayton

Sent from my LM-V350 using Tapatalk

Thanks I'll check out their rebuild kits!

Sent from my SM-G950U using Tapatalk

 

[bucket]

Give Cliff Ruggles a call.
cliffshighperformance.com

Make sure you have the number from the carb. He'll get you squared away. Wouldn't hurt to buy abd read his book either. You'll be amazed what you'll learn.

I agree with the above ^

 

[legopnuematic]

Stay away from remaned or 'rebuilt'carbs from a big company typically will have a sticker or tag on them. Quadrajets were put on mid 200ci (like 240ci) engines all the way to 500ci caddy's, those companies will typically blow them apart and use the best parts to piece them back together, so you may very well end up with a throttle plate from a 350, air horn from a 4.3 v6 and a mid section from a 454, and then it runs like hot garbage. $20 will get you a rebuild kit from any parts house, or spend the extra for one from cliff, rebuild>reman.

Sent from my Moto Z (2) using Tapatalk

 

[Matt69olds]

If the carb was recently rebuilt, and you have no accelerator pump shot, I would be willing to bet when you take it apart your going to find the accelerator pump piston in 2 pieces. The problem is today’s fuel attacks the old rubber parts, causing them to either get really soft, or expand and lock in the bore. That’s what happened on my Q-Jet. No accelerator pump, took it apart to find the piston pulled apart from the plunger. I had another pump from a old rebuild kit, it lasted a few months until it happened again. Got a new pump from Cliffs Q-Jet, along with some other tuning parts, and I ran great for years.


https://cliffshighperformance.com/Q.../quadrajet-standard-accelerator-pump-assembly

Cliff really knows what he is doing with Q-Jets. I’d suggest buying his book, there is a wealth of knowledge your not going to find in a service manual. Good luck, all of us “experts” were beginners at one time. Hang in there, ask questions. Only way to learn.

 

[TerryRH]

Where abouts are you, Dawson?

 

[thecantaloupeman]

Where abouts are you, Dawson?

I'm in good ol Colorado

Sent from my SM-G950U using Tapatalk

 

[thecantaloupeman]

If the carb was recently rebuilt, and you have no accelerator pump shot, I would be willing to bet when you take it apart your going to find the accelerator pump piston in 2 pieces. The problem is today’s fuel attacks the old rubber parts, causing them to either get really soft, or expand and lock in the bore. That’s what happened on my Q-Jet. No accelerator pump, took it apart to find the piston pulled apart from the plunger. I had another pump from a old rebuild kit, it lasted a few months until it happened again. Got a new pump from Cliffs Q-Jet, along with some other tuning parts, and I ran great for years.


https://cliffshighperformance.com/Q.../quadrajet-standard-accelerator-pump-assembly

Cliff really knows what he is doing with Q-Jets. I’d suggest buying his book, there is a wealth of knowledge your not going to find in a service manual. Good luck, all of us “experts” were beginners at one time. Hang in there, ask questions. Only way to learn.

Hopefully I'll be in a similar situation as you and only need to replace the Pump. That will likely be a bit easier than rebuilding the whole thing. Chances are if I looked the rest over it would all be fairly good since he rebuilt it recently. The gaskets definitely look new. But I might give that book a try, it's 20 bucks on Amazon with two day free shipping!

Sent from my SM-G950U using Tapatalk

 

[Rusty Nail]

I guess simply pressing the gas slower isn't an option?
What did I miss?

 

[thecantaloupeman]

I guess simply pressing the gas slower isn't an option?
What did I miss?

Well its an option, but I have to accelerate extremely slow at lights for it to not stall. Not only can this be dangerous, but I could still stall at any time because my accelerator pump is shot and I could end up in an accident, ruining my beautiful new 78 C20.

 

[TerryRH]

I'm in good ol Colorado

Sent from my SM-G950U using Tapatalk

If you were closer I'd put you to work. Troubleshoot your truck, and I've got plenty here you can learn on

 

[Nonstop]

Honestly, if this is your only transportation, I would consider slapping on a used carb from the junkyard or from a friend and make the truck safe to drive for now. Take the one that is on there and have it professionally rebuilt.

I respect that you want to learn and I am seeing the questions you are asking and eagerly learning. If this is your only mode of transportation, it is a pain in the ass if you replace the accelerator pump, do not put it back together right, and have to take it off and take it apart a few times. Quadrajets can be intimidating, as can any carb at this level for you. Again, not knocking you in any way, simply speaking from having been young and learning as I went.

Once this is rebuilt, take the used one off and tear into it and use that one to learn on.