Help with 85' Grand Prix

[Psychopete]

Hey All,
I am new to Chevy and carburetors in general, I have an 85' Grand Prix with a Monza Spider 262 that I just purchased. It drove fine to my friends, about 50 minutes, no problems. Drove it back to my house after getting it plated, started right up, everything seemed okay. Drove it to work, same thing. Driving home, I get on it a little, let off the gas, and it just died - wouldn't start back up. I messed around for about 10 minutes, finally got it to fire, floored it, slowly worked up from low RPMS to 3,000. Smoked like hell. It seemed okay, but it felt like it wanted to die another time. I could not get it to start this morning, it would fire, but it just didn't want to keep running. The engine apparently has a mild cam and the guy told me it has a 4bbl. carb. The carb looks fairly old.

My first thought is fuel delivery problem, I haven't had a chance to rip into it yet, I was wondering if anyone had any suggestions? By the way it smells, I am inclined to think that it's too running rich and the plugs are possibly fouled. If this is the case, what is going to be the best way for me to get the a/f ratio correct? I've been told so many different things, I am not certain where to start.

Thanks in advance,
Pete

[GTP Dad]

It sounds like a stuck float in the carb. They will stick causing a lot of fuel to be dumped into the engine and it will run very rich. Based on the year, purchase a carb rebuild kit and rebuild the whole thing. I think you will be quite surprised by the changes in drivability.

[Psychopete]

Originally Posted by GTP Dad

It sounds like a stuck float in the carb. They will stick causing a lot of fuel to be dumped into the engine and it will run very rich. Based on the year, purchase a carb rebuild kit and rebuild the whole thing. I think you will be quite surprised by the changes in drivability.

Thank you for the response. What will be the best determination of this? I could see fuel getting into the oil for one. The car sat for a little while before I purchased it, what you're saying is makes sense. You're probably right about the carb in need of rebuilding, it's looking fairly old. I may replace it with a Edelbrock 500cfm, I am not sure where the carb on it now came from. I will have to dig around to see if that particular motor came w/ a 4bbl. Is there usually any numbers that I could reference on the carburetor itself?

Pete

[mike561]

not too often we get the older cars on here, good to see though, i like older cars as well.

[GTP Dad]

The carb should have a tag on it indicating the type and manufacturer. If it is a quadrajet they are almost all the same with few differences. Try the newer carb. I bet the issue will go away. You can try tapping the float bowl with a small hammer or screwdriver while it is running to see if the problem subsides for a time. Make sure you only tap. If you hit it too hard it will damage it.

[Psychopete]

Originally Posted by GTP Dad

The carb should have a tag on it indicating the type and manufacturer. If it is a quadrajet they are almost all the same with few differences. Try the newer carb. I bet the issue will go away. You can try tapping the float bowl with a small hammer or screwdriver while it is running to see if the problem subsides for a time. Make sure you only tap. If you hit it too hard it will damage it.

Yea, it was a Quadrajet. Bought new plugs and carb kit for $40, spent about 2 hours rebuilding the carb. The choke was also not hooked up and was closed all the time. I am leaving it open for now, but am planning on making it just a manual choke w/ cable. The problem appears to have cleared so far, the motor overall runs suprisingly better. Thank you for all of your help.

Pete

[GTP Dad]

Glad I could help. The manual choke is the way to go. That way you can control it rather than rely on the electric choke that can be problematic. It is unfortunate that the carb has gone the way of the dinosaur since they were much easier to work with but they just can't meet the emissions regulations and fuel mileage like the newer injection systems. You have to be an old hot rodder or a drag racer to remember how these things act.

[Psychopete]

Just an update...

The 262ci V8 in the Grand Prix starting making noise (knocking / warm), and I swapped a 327 as a replacement. Under closer investigation, the idoit past owner relied on self-tapping bolts to hold the lower motor mounts in. The exhaust was a joke, leaks everywhere. I also came to the conclusion that the torque converter was screwing up on the TH350. $1,400 later, it runs again!





The Chevy 262ci V8 must be junk, I can hardly give the thing away. I think I might part it out, if anyone needs any various SBC parts for cheap. It would make a good rebuild, but it didn't have enough power for me.

The 327 has taken out a Mustang GT 5.0L. I am curious to see what it has on my S/Ced 2.9L Ranger once it's done . That Edelbrock carb on that motor was a 750CFM and just ran too rich, I replaced it with a 650CFM holley double pumper. Runs wwaayy better. I am a big fan of holley regardless. Going to replace the Victor Jr. w/ a dual plane high rise intake later in the spring. Also have centerline rims to install, might paint it black if I have any money to put into it after finishing other projects.

Pete

Edit: Oh yeah, my original problem was probably because apparently the quadrajet had some sort of computer control. I was not aware of this (I've mainly worked on Fords, as that is all I have owned prior to this Pontiac), some guy was telling me it would run rich by default if the electronics were unplugged.