OK, this is my first carb'ed car so this kind of stuff is new to me.

The other day, when I'm in bumper-to-bumper traffic the van in front of me takes off and I slam on the gas to keep pace (Maybe 3/4 throttle, NOT full throttle) and my rev's go up a bit(Like 100RPM's or so) and I feel/hear the engine bog, stumple, then stall. I started it up again, except stupid me stepped on the gas hard again (HUGE line behind me) and it stalled again.

For the next couple minutes, any time I had to go forward in traffic I had to really baby the throttle. As I did this I could feel it bogging, but it didn't stall. I just went REALLY slow until the rev's got up to 1200 or so, then I could step on it. This seems to only happen for about 5-10 minutes after I start it. After that, it goes away. It doesn't happen every time either. It's very off and on problem.

I asked my dad and he told me "...that's the way carburetored cars are, live with it...". However, I told a good friend this, who is also very mechanically-inclined like my dad, and he told me that it shouldn't do that AT ALL and that a good shop would be able to tune it for me. He recommended a race shop of his friends.

But before I take it there, I wanted to ask you guys with carb's, do you have to live with this sort of stuff? To me, this doesn't seem very "streetable" if I'm stalling in rush hour traffic. Days like that, and I really start to miss my Talon and almost makes me want to pull my Laser out of storage early...

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Trevor
87 Z28 - LG4 - 305
Hedman Headers, Y-Pipe, Dynomax Exhaust, K&N Open Air Filter

http://immortaltk.tripod.com/z.html

 

Oh, and in case it's of importance I'm running an open air element.



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Trevor
87 Z28 - LG4 - 305
Hedman Headers, Y-Pipe, Dynomax Exhaust, K&N Open Air Filter

http://immortaltk.tripod.com/z.html

 

hey trevor,
no way do you have to live with this problem. A properly functioning carb should not do this. But you need to provide a little more info. Is this carb a computer controlled quadrajet or an aftermarket? Also is it a new or rebuilt carb or the orignal?

 

It's the stock quadrajet, but I do not know if it's computer controlled or not. It's also the original carb.

I did some testing tonight, and here is what happens exactly. I start my car, my fast idle kicks in. I put it into gear (Warm up maybe 10-15 seconds) and drive away. It then idles at just above 500RPM in drive, and will bog when the gas is pressed.

Once it is fully warmed up, it idles at 750RPM and does NOT bog at all. It runs really smooth.

Any other ideas on what it could be with this new information?

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Trevor
87 Z28 - LG4 - 305
Hedman Headers, Y-Pipe, Dynomax Exhaust, K&N Open Air Filter

http://immortaltk.tripod.com/z.html

 

Trevor,

Check the accellerator pump. Load up this file for a diagram:

E4ME Carburetors.pdf

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Later,
Vader
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"Click - Click - BOOM! Saliva - American Outlaw"
Adobe Acrobat Reader

[This message has been edited by Vader (edited September 10, 2001).]

 

The diagram's nice Vader, but he doesn't have an E4ME.

 

Mine does the exact same thing... I'm pretty sure mine's a sticking choke tho. Check and see if the choke is actually engaging when you start it up cold... might just need a good cleaning.

Arawn1

 

My non computer controlled quadrajet does the same thing. On mine the secondaries are opening too quickly. The opening of the secondaries is controlled by vacuum. There is a vaccum "Motor" that doesn't allow the secondaries to open until the rpms come up. There is no accelerator pump on the secondaries so if they are opening too quickly the motor will bog.

 

Your choke is set wrong. You're a fool if you pay someone to fix it.

You'll most likely have to drill out the rivets on teh choke cover so you can adjust it. Then use either self tapping screws, or a nut/bolt to hold the cover so you can adjut it. You need more choke, so you need to turn it CLOCKWISE. You'll see little tick marks on a spot on the cover. Put amark on the choke housing to reference the tick marks. Move it 2 ticks clockwise and see how it does. If completely better, maybe try backing off 1 tick. If it still isn't perfect, go richer still. You'll know when you're too far cuz it will develop a miss. Ideally you want as little choke as possible to avoid this situation. You'll obviously want to make sure everything is clean and moving OK.

Fun Fact of the Day: Choke tuning - lean stalls, rich misses.

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Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
305 TPI A4 2.73 - 14.8 @ 93.1
Stock except ported plenum and dual cats
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die