Bogging down on hard accel

[Jack]

Sounds like Qjet's Power Piston could be sticking and not letting the needles rise and fall from the jets as needed. Make sure there's NO grit (1 speck can seize the PP), gum, varnish or burrs in PP's bore or on PP ... LIGHTLY polish the PP w/ fine scotchbrite. Once you think everything's clean ... clean it 2-3 more times.

And dumber things have happened ... if you have a paper filter in Qjet (probably) ... make sure it's not in backwards. The end with hole should point TOWARD fuel line. Otherwise, it'll run but it'll wanna starve.
JACK:gap

 

[sothpaw]

For what it's worth, my '86 Trans am had a 4-barrel carb and 164 k mi when I sold it and I never had to do any special procedure to keep it from bogging cold.

I never floored it cold but I sure did accelerate it and I wasn't careful.

So what you describe is not at all normal IMHO. You shouldn't have to baby it.

 

[Adam Wartell]

Just thought I'd give you an update...

I sent an email to the owner of the shop, which is County Corvette in West Chester, PA, by the way. I explained the situation and that I expect they should get it back to proper running condition.

The next morning, I got a call from the mechanic there that worked on my Vette. He seemed surprised that I was still having trouble, even though it had left there in the same condition I am complaining about. He suggested that maybe the Accelerator Pump has gone bad, which he said was replaced when he rebuilt the carb.

At any rate, I'm taking it back to them this Wednesday. I'm hoping and expecting that I will not have this problem any more when I get it back!

 

[atmmac]

why are you going to a corvette shop..... Just check out the mechanic you use for most of your cars. A carbureted 350 is a pretty basic motor and im pretty sure any mechanic can work on it. My car goes to a regular shop and its a lot harder to work on with all the electronics!! I guarantee that that shop is probably ripping you off and just taking there sweet time in doing it.

 

[LT4man]

All of the adjustments on any type of carburetor can be made with the engine off. It does not matter if the engine is hot or cold. After the proper adjustments are made, the car can be started cold (after sitting overnite) to check how the car runs. The choke pull-off adjustment is extremely critical to the engine running well when cold. Even upon heavy (hard) acceleration, the engine should pull without any hesitation at all. Of course, when the engine is warm, the secondaries will open allowing the engine to have more power.

I will admit that some people and some technicians find it difficult to work with a carbureted engine. I grew up and learned my trade when 99% of the engines out there had carburetors. I had plenty of carburetors to practice on. Most of my customers came to me with driveablility problems that no one else could fix. I was very patient with the carbs and moreso with my customers. They would be very frustrated by the time they found me. :confused

If your technician listens carefully to you (the MOST important part of this equation) and spends the time necessary to adjust your carb, both of you should end up being very pleased. You, because your car is running well and he, because he has another satisfied customer!

Save The Wave!

 

[lucky76]

It sounds like your choke is not working. Test your choke by doing this. Before starting your car in the morning, remove the top of the air cleaner. Don't start it, but press the gas to the floor. Does the choke flap close? It should close nearly all the way but not completely. If it doesn't close at all then it's not adjusted correctly or something is wrong with it. If is does close then start your engine and let it run for a while. Every 30 seconds tap the gas, you should see the choke open some as it warms up. After a few minutes it should open completely and the engine speed should slow down to normal. Put the top back on the air cleaner.
If it needs adjusting you can only adjust it when it's cold so wait until the cools completely again or the next morning before adjusting it.

 

[Adam Wartell]

Thanks for all the comments & advice gang!

I have checked the choke, and it seems to be operating as you say it should.

Here's an update for ya:

I dropped it back off at County Corvette yesterday. Of course, I couldn't show them the problem, since it has to be cold to do it. But they said that they'll try some other things, like the accelerator pump, to see if they can get it right.

It has also been running really crappy, but of course, seemed to be running ok while I was there!

As I left, the president of the shop took it out for a drive.

I really hope they can get this right!

I'll keep you posted...

 

[magoo]

You certainly have put up with it long enough by now. I thought maybe it was fixed and you just hadn't got back to us. Keep us posted and good luck.

Mike

 

[Grizzly]

The accelerator pump is either mis-adjusted, not connected, or the pump piston is shot and wasn't replaced during the rebuild. Has nothing to do with the secondaries or the choke.

I agree................