3.8 Buick

Street Sweeper22

Greasemonkey
Nov 18, 2017
102
28
I have a 1984 Buick Regal Limited with a 3.8. The issue I’m having is that I have to pump it about 10 times for it to start. It will start and idle just fine and then it will just start to hiccup and run choppy. It will run like the 125 hp beast that it is at high rpm but at idle and low rpm it stumbles. It does smell like gas when I start it. About 50% of the time it runs smooth. My unprofessional opinion is mechanical fuel pump. What do you guys think? Any help is greatly appreciated besides put a SBC in it. Thank you
 

PVDave

Not-quite-so-new-guy
Oct 28, 2021
30
8
Arvada, CO
The issue I’m having is that I have to pump it about 10 times for it to start.
You typically pump a carb to shoot raw fuel down the intake using the accelerator pump. If it takes ten pumps to start, I'd check the pump operation. Prop the choke plate open and work the throttle open and closed. If the accelerator pump is good, you should see a stream of fuel shoot down the car's throat.

It does smell like gas when I start it.
Gas smell out of the tailpipe? If so you have a rich problem. If you smell gas under hood, check for leaks around the car and on the fuel feed line between the fuel pump and carb.
 

CrammerGram69

Master Mechanic
Nov 15, 2019
338
43
SW, Michigan
84 has the ccc computer bs system so it's probably your worn-out carb that needs to be rebuilt, or maybe part of the computer thing that controls it all. i like the idea of staying 3.8.
 

MrSony

Geezer
Nov 15, 2014
6,385
113
Des Moines, Iowa
Check and make sure the choke is operating. It should have a slight tension and snap shut when cold if you fully open and close the throttle once. It should fully open and not be floppy when the engine is warm. If it takes 10 pumps to start the accelerator pump could be weak. Old rubber and modern fuel don't go well together. The gas smell could be a number of things. Check for wet areas around the carb. If the carb floods it can puke out the accel pump rod hole, if you have the original two barrel Rochester.
 

Street Sweeper22

Greasemonkey
Thread starter
Nov 18, 2017
102
28
You typically pump a carb to shoot raw fuel down the intake using the accelerator pump. If it takes ten pumps to start, I'd check the pump operation. Prop the choke plate open and work the throttle open and closed. If the accelerator pump is good, you should see a stream of fuel shoot down the car's throat.


Gas smell out of the tailpipe? If so you have a rich problem. If you smell gas under hood, check for leaks around the car and on the fuel feed line between the fuel pump and carb.
Gas under the hood. I took the carb off and cleaned it last year and put new gaskets on it. The kit did come with a new accelerator pump but I didn’t know how to take the spring off the old one and put it on the new one. I didn’t want to mess up the spring. If it sits over night I just have to pump it a couple of times. Any longer than that it’s like all the fuel drains out of it. I will check tomorrow and see if the pump is spraying fuel before I start it.
 

Street Sweeper22

Greasemonkey
Thread starter
Nov 18, 2017
102
28
Check and make sure the choke is operating. It should have a slight tension and snap shut when cold if you fully open and close the throttle once. It should fully open and not be floppy when the engine is warm. If it takes 10 pumps to start the accelerator pump could be weak. Old rubber and modern fuel don't go well together. The gas smell could be a number of things. Check for wet areas around the carb. If the carb floods it can puke out the accel pump rod hole, if you have the original two barrel Rochester.
Yeah I had to adjust the choke when I moved from Arizona back to Colorado and that helped a bunch. To be honest the worst part is how crappy it runs under 30 mph. Above 30 it runs good and this just started. It’s even died on me a couple of times at a stop sign. It will start right up and go like nothing happened.
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,180
113
Here's the thing about your engjne...

When you took off and replaced the carb, did you install (or was there even still present) the E.F.E.?

It looks like a thick carb gasket with a wire coming off, usually grey plug. In the center would be two recessed metal square grids that sit into the intake surface.

Cold starts the computer heats the wire elements, which helps vaporize the fuel going in aiding in combustion, lowering emissions/unburnt fuel, etc etc etc.

Those are often missing, or, as you may expect, over time the wire grids melt and thus don't perform their function.

Now, what else can lead to fuel smell.... your charcoal canister could have a saturation issue or the fabric pad could have been damaged resulting in granule loss.

Another brainstorm? Instead of pumping the carb ten times, give it a different test. One day do your normal 10 pump routine, but, count how long you're cranking the engine while punching the pedal. Let's pretend it's 20 seconds. On day two, crank the engine for 70% of that time without pedal use. Then, release key, pump 3 times, and turn key trying to start. See if it fires up, or, if you only need to pump it once or twice during the second set of cranking.

That test would be to see if you were having leakdown of the fuel bowl and all that time pushing the pedal, well, if there's no fuel in/at the carb yet your pushing a pedal to release air while waiting for the fuel pump to suck fuel from the tank, to the carb, so on so forth. If that's the case we know other things to look at, and for.

I'd venture you've got a few things going on, amd, have you done the timing gears yet?
 
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Street Sweeper22

Greasemonkey
Thread starter
Nov 18, 2017
102
28
Here's the thing about your engjne...

When you took off and replaced the carb, did you install (or was there even still present) the E.F.E.?

It looks like a thick carb gasket with a wire coming off, usually grey plug. In the center would be two recessed metal square grids that sit into the intake surface.

Cold starts the computer heats the wire elements, which helps vaporize the fuel going in aiding in combustion, lowering emissions/unburnt fuel, etc etc etc.

Those are often missing, or, as you may expect, over time the wire grids melt and thus don't perform their function.

Now, what else can lead to fuel smell.... your charcoal canister could have a saturation issue or the fabric pad could have been damaged resulting in granule loss.

Another brainstorm? Instead of pumping the carb ten times, give it a different test. One day do your normal 10 pump routine, but, count how long you're cranking the engine while punching the pedal. Let's pretend it's 20 seconds. On day two, crank the engine for 70% of that time without pedal use. Then, release key, pump 3 times, and turn key trying to start. See if it fires up, or, if you only need to pump it once or twice during the second set of cranking.

That test would be to see if you were having leakdown of the fuel bowl and all that time pushing the pedal, well, if there's no fuel in/at the carb yet your pushing a pedal to release air while waiting for the fuel pump to suck fuel from the tank, to the carb, so on so forth. If that's the case we know other things to look at, and for.

I'd venture you've got a few things going on, amd, have you done the timing gears yet?
There’s a thick carb gasket but no metal grid. And no I haven’t done the timing gears. I will try the different routines like you said and keep you posted. I appreciate your help.
 

MrSony

Geezer
Nov 15, 2014
6,385
113
Des Moines, Iowa
If everything is working you're only supposed to pump the carb one time.
Look down the carb (engine off overnight cold) and see if you can see fuel shooting out of the discharge holes as you open the throttle. It will run out eventually after a few pumps. If there is no fuel coming out, the accel pump is bad or there is not enough fuel getting into the carb.
I have noticed a very clear difference in how my v6 and now my 350 run on ethanol laced fuel vs straight gasoline.
If youve ever overfilled the tank it can back up through the vapor line into the charcoal canister and cause issues. Temporarily unhook it from the carb and see if it runs any better.
 

jiho

G-Body Guru
Jul 26, 2013
928
63
Colorado? Like mile high? My guess, you need altitude adjustment. At higher speed the throttle is open, so more air. The air is thinner up there, it needs more air with the throttle plate closed.
 
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