Stalls when pressing gas too fast

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,250
Reaction score
17,177
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
To filter the fuel. If it is open no fuel is filtered.
 

Nonstop

Full Access Member
Joined
Nov 16, 2014
Posts
775
Reaction score
2,421
Location
Ca
First Name
Nick
Truck Year
1985
Truck Model
K2500
Engine Size
454
It is a check valve. Install it toward the nut/fuel inlet into the carb.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
To filter the fuel. If it is open no fuel is filtered.
Oh so I am supposed to take that off the old filter and put it on the new one? Should I take that paper gasket off then? The old one didn't have that.

Sent from my SM-G950U using Tapatalk
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,250
Reaction score
17,177
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
It's supposed to come with one, or one end is closed by design. Meaning one end open, the other is metal. Have seen both, metal and the rubber gasket on the downstream end. But it can't be open on the downstream end
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
It's supposed to come with one, or one end is closed by design. Meaning one end open, the other is metal. Have seen both, metal and the rubber gasket on the downstream end. But it can't be open on the downstream end
Well the side that goes against the spring is closed (metal) and the other open with a gasket. My old one is the same but instead of the paper gasket its got that rubber thing that sticks inside the filter with a spring inside it, and also acts as a gasket. Its weird that the new one didnt have one. The one I got that was the wrong length came with one. Maybe its just not meant for this carb, or maybe its just a different design and still works.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Start with the fuel filter, then check the accelerator pump. Look down the throat with the engine off. Open the throttle using the arm and look for 2 strong streams of gas (one from each side).

Also check for any vacuum leaks. All these are relatively easy starting places.
Will the streams be pretty obvious? If I don't see them what does it mean? Is fixing an accelerator pump an easy task?
 

Nonstop

Full Access Member
Joined
Nov 16, 2014
Posts
775
Reaction score
2,421
Location
Ca
First Name
Nick
Truck Year
1985
Truck Model
K2500
Engine Size
454
Streams are pretty obvious - like two little men pissing down the carb primaries.

If it is the accelerator pump, with all due respect, easiest will be to have a shop replace the pump, or have them rebuild the carb. There are a lot of small parts in a carburetor.
 

DBarre

Full Access Member
Joined
Jul 15, 2014
Posts
124
Reaction score
265
Location
Rockport, Texas
First Name
Dustin
Truck Year
1981
Truck Model
C10
Engine Size
250c.i./4.1L
Well the side that goes against the spring is closed (metal) and the other open with a gasket. My old one is the same but instead of the paper gasket its got that rubber thing that sticks inside the filter with a spring inside it, and also acts as a gasket. Its weird that the new one didnt have one. The one I got that was the wrong length came with one. Maybe its just not meant for this carb, or maybe its just a different design and still works.

The new replacement filter is probably just made cheaper with the paper gasket. You should probably watch some youtube videos about carburetors to understand how they work. It could help you diagnose any issues you may be having. Then, if you have more questions, you can better describe the issue. I've started watching Uncle Tony's Garage and, even though he's a Mopar guy, he really knows his stuff.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,441
Reaction score
28,345
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Why are you guys making so much fun?
I mean come on, we all had to start somewhere.

Yep. When I was younger and learning, all I had was dad to show me some things, or I figured it out myself. Lots of trial and error. I bet if I would have had internet forums, I'd a asked a bunch of questions too. Or at least googled all kinds of crap.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Streams are pretty obvious - like two little men pissing down the carb primaries.

If it is the accelerator pump, with all due respect, easiest will be to have a shop replace the pump, or have them rebuild the carb. There are a lot of small parts in a carburetor.
Actually I don't think I've mentioned that the carb was rebuilt right before I got the truck. Is it likely he messed it up?
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Yep. When I was younger and learning, all I had was dad to show me some things, or I figured it out myself. Lots of trial and error. I bet if I would have had internet forums, I'd a asked a bunch of questions too. Or at least googled all kinds of crap.
Thank you! My Dad has no idea how to work on cars or even use power tools. I really just need a source to ask questions, because I don't know anyone yet who can mentor me. It's nice to have this even though I may be overusing it a bit. If I had a lot of money and maybe another car, I'd be fine with messing around until I figured it out, but I don't. If I screw something up, I could be out a lot of money and possibly my car If I break it beyond something I can fix or pay to get fixed.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
The new replacement filter is probably just made cheaper with the paper gasket. You should probably watch some youtube videos about carburetors to understand how they work. It could help you diagnose any issues you may be having. Then, if you have more questions, you can better describe the issue. I've started watching Uncle Tony's Garage and, even though he's a Mopar guy, he really knows his stuff.
I checked out that Uncle Tony guy and watched his video on carbs. He really does know his stuff. He didn't have a script or anything, just talked for a half hour about how carbs worked like he was a college professor. Pretty awesome! Thanks for the recommendation.

I put that other duralast filter in and it didn't seem to solve my problem. Just for giggles I went to NAPA and I asked what the rubber thing was. He said it was called a restrictor. Apparently it's just an added feature, but they had a filter for my truck in stock with a restrictor and it was 4 bucks so I'm gonna just use that one. It is much more similar to the old filter that came out of the carb.

I'm sorta curious though why my truck uses the short filter. Most videos of people with the 5.7L have the long filter. When I put that into the auto parts store computer it says I need the long one. My carb obviously wont fit the long filter so maybe it isn't original to the engine. It got me thinking maybe it's taken off another vehicle and that's why the owner claimed it was "rebuilt".

If it isn't rebuilt that could explain why my accelerator pump could be an issue. I still have to go check that, but it seems likely after some research that my symptoms match the accelerator pump failure.
You must be registered for see images
You must be registered for see images attach


Sent from my SM-G950U using Tapatalk
 

Craig 85

Full Access Member
Joined
Jan 25, 2017
Posts
3,917
Reaction score
4,116
Location
Nashville, TN
First Name
Craig
Truck Year
1985
Truck Model
K30 SRW
Engine Size
454/TH-400/NP205
To make sure you are getting the correct parts for your carburetor, there should be numbers stamped on the driver's side rear corner. He's mine. Your's should have 8 digits for a '78 and start with 1705****

http://www.carburetion.com/quadnumber.htm

#17084502 - Breakdown
1708 - 80's
4 - Production year - 1984
5 - Quadrajet (4 bbl) California standards
0 - Chevrolet
2 - Even - Auto trans
You must be registered for see images attach
 

Latest posts

Forum statistics

Threads
44,163
Posts
950,693
Members
36,276
Latest member
2manysquares2care
Top