[alconk]

Hello everyone, I would like some help because I just can't find the problem. My car is a 81 T/A that has had the computer removed, HEI dist. installed and a NOS 1980 non-computerized T/A quadjet. The proble is that it idles rich, so rich that black carbon spurts out the tailpipes. I've adjusted the mixture screws and it doesn't help. I also are having a hard time setting the idle screw. I can get it just perfect and once it's turned off and restarted it's either lower or higher rpm???? The carb has been checked and another engine and it doesn't do any of the following. I have checked everything but now I'm leaning towards a possible intake leak. Could that promote this problem?? Also my vacumn is about 15-17 at idle, it should be around 18-22. What am I missing??

[alconk]

Hello everyone, I would like some help because I just can't find the problem. My car is a 81 T/A that has had the computer removed, HEI dist. installed and a NOS 1980 non-computerized T/A quadjet. The proble is that it idles rich, so rich that black carbon spurts out the tailpipes. I've adjusted the mixture screws and it doesn't help. I also are having a hard time setting the idle screw. I can get it just perfect and once it's turned off and restarted it's either lower or higher rpm???? The carb has been checked and another engine and it doesn't do any of the following. I have checked everything but now I'm leaning towards a possible intake leak. Could that promote this problem?? Also my vacumn is about 15-17 at idle, it should be around 18-22. What am I missing??

[gtohurstjudge]

Your problem is most likely a bad purge valve.
The purge valve is a black plastic device with
several vacuum lines going to it, one of which is a 3/8 line going to the bowl vent tube on the top front of the carburetor. When the vacuum diaphragm on the purge valve fails, a
massive vacuum is created on the line going to the bowl vent and this vacuum sucks raw fuel out of the carb bowl like a vacuum cleaner! The
raw fuel goes directly into the intake via the other vacuum lines on the valve and you basically have a fuel delivery system which is bypassing the carburetor completely! Disconnect
the bowl vent line at the front top of the carb and see if it has massive vacum when the engine is revved. If it does, this is your problem.
GTOHURSTJUDGE

[pontiac81]

CHECK YOUR EGR VALVE IT MAY BE STUCK. MY TA IS ALSO AN 81 AND I CHANGED THE CARB, DIST, AND TRANS, I MADE A BLOCK OFF PLATE AND GASKET TO DELETE THE EGR VALVE AND MINE RUNS SUPER STRONG.

[alconk]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by gtohurstjudge:
Your problem is most likely a bad purge valve.
The purge valve is a black plastic device with
several vacuum lines going to it, one of which is a 3/8 line going to the bowl vent tube on the top front of the carburetor. When the vacuum diaphragm on the purge valve fails, a
massive vacuum is created on the line going to the bowl vent and this vacuum sucks raw fuel out of the carb bowl like a vacuum cleaner! The
raw fuel goes directly into the intake via the other vacuum lines on the valve and you basically have a fuel delivery system which is bypassing the carburetor completely! Disconnect
the bowl vent line at the front top of the carb and see if it has massive vacum when the engine is revved. If it does, this is your problem.
GTOHURSTJUDGE <HR></BLOCKQUOTE>

[alconk]

Well actually you're right. My canister was so full of gas that it took several days for it to dry out. I have disconnected all the hoses except the one that goes to the air cleaner and the gas tank. The carb has all the ports capped off except for the timing. I'm not running a EGR it's been blocked off with a plate and the damn car still runs rich at idle.I'm going to pull the intake and have it boiled out and reseal it back up and see what that does. Who knows???? Should I run with that canister hooked up to the carb?? <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by alconk:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by gtohurstjudge:
Your problem is most likely a bad purge valve.
The purge valve is a black plastic device with
several vacuum lines going to it, one of which is a 3/8 line going to the bowl vent tube on the top front of the carburetor. When the vacuum diaphragm on the purge valve fails, a
massive vacuum is created on the line going to the bowl vent and this vacuum sucks raw fuel out of the carb bowl like a vacuum cleaner! The
raw fuel goes directly into the intake via the other vacuum lines on the valve and you basically have a fuel delivery system which is bypassing the carburetor completely! Disconnect
the bowl vent line at the front top of the carb and see if it has massive vacum when the engine is revved. If it does, this is your problem.
GTOHURSTJUDGE <HR></BLOCKQUOTE> <HR></BLOCKQUOTE>

[gtohurstjudge]

You don,t have to run the car with the canister
and purge valve hooked up. This would be an
evaporative emissions issue only. However without the canister/purge hooked up you may notice a gasoline odor in the garage when the car is parked there .GTOHURSTJUDGE Also, sometimes when you have a bad purge valve, the
suction sucks dirt up into the needle and seat
and causes the carb to need an overhaul. This
would be my guess as to why it still floods.

[KSZR]

Originally Posted by alconk

Hello everyone, I would like some help because I just can't find the problem. My car is a 81 T/A that has had the computer removed, HEI dist. installed and a NOS 1980 non-computerized T/A quadjet. The proble is that it idles rich, so rich that black carbon spurts out the tailpipes. I've adjusted the mixture screws and it doesn't help. I also are having a hard time setting the idle screw. I can get it just perfect and once it's turned off and restarted it's either lower or higher rpm???? The carb has been checked and another engine and it doesn't do any of the following. I have checked everything but now I'm leaning towards a possible intake leak. Could that promote this problem?? Also my vacumn is about 15-17 at idle, it should be around 18-22. What am I missing??

I seems I have the same problem. Will check it out with the advice from this thread.

[Sirrotica]

FWIW, from working at a GM dealership, the canister will sometimes rupture internally, the charcoal will then be pulled into the float bowl of the carb causing flooding. I have taken apart carbs that had the fine charcoal in them, cleaned them, and they flooded again within 10 minutes.

Upon disassembly they again were contaminated with charcoal particles. Replace the canister, and no further problems. It's not a real common problem, but I have seen it happen 3-4 times.

[KSZR]

Thanks! I don't think I'm pulling extra fuel through that system as suggested with the failed valve.

Seems like maybe the choke isn't fully opening fast enough. Need more time to mess with it.

If this isn't it then I'll dig deeper like you suggest with the canister. Probably be good to replace no matter what considering how old it is.