83 Buick Regal with 4.1 has no ZOOP.

[3972plymdodge]

My daily driver is an 83 Buick Regal (old enough to vote so I like it) with a 4.1 V-6 and Quadrajet carb.

Been driving it for 5 years now. Fine car except that it is very slow on acceleration. Almost dangerous when trying to merge into high speed traffic.

Seems like a 4.1 on a fairly light car should be pretty fast. ..

Pump on carb seems to work ok. (Hear squirting noises)

Only thing obvious I notice is that there is a linkage disconnected (probably never hooked up) on the passenger side of the carb running from what Chilton's calls a rear vacuum break (it is hooked to a vacuum line). That linkage is hooked up to the vacuum break but the other end just lays on top of the intake manifold.

As far as I can tell the secondary barrels are locked up without something to release them. So---my opinion is that is the purpose of that rod that goes nowhere right now.

Trouble is I can't find anything to hook that rod up to. Hard to see well behind the choke, but using a flashlight and mirror I just don't see any obvious hole to hook the other end of the rod to.

Would take the choke off to get a better look but it (at least the cover plate) seems to be riveted in. There must be screws somewhere but I think you have to remove the rivets to get at the screws. Could drill out the rivets and go from there, but what do I replace the rivets with?

Anyway what should be a very simple problem---linkage never hooked up and therefore secondary barrels of a 4 barrel carb can't work---is getting a little difficult.

Any help appreciated from Buick techs out there. Especially suggestions on how to remove the choke so I can see what is behind it better. Or suggestions as to where the other end of that rod is supposed to go so I can hook it up without removing the choke.

(I have 2 other cars but they aren't running right now. And I do need my Buick for daily transportation to work. So don't want to start something I can't finish.)

Hope this all makes some sense.

[Guest Straight eight]

They are supposed to have zoom zoom zoom.

I had one, and had several accelerator pumps replaced which fixed the problem gasoline was blamed for the pump failures. Sorry I don't know about the vacuum brake.

[NTX5467]

Sounds like a combination of issues . . . some of which are somewhat "common" with Q-Jets in general.

Could be an accel pump issue, but if you pump it and it "helps", it could also be the "power piston" in the carb (which moves the primary metering rods up and down, moving against a calibrated coil spring under it that is the basic phasing of when the metering rods let "power" or "economy" mixtures happen) is stuck in the "down" or "economy" position. Could also be that the spring has broken and it's in the down position all of the time. A quick way to check is to put a large blade screwdriver gently down through the interior bowl vent tube (in the middle, in front of the primary barrels) and then load the engine against the foot brake. More throttle = less manifold vacuum = screwdriver moves upward. Less throttle = more manifold vacuum = screwdriver moves down from its low vac position. If no movement, then the power piston is not moving as it should or the screwdriver is not sitting on the valve--or it's an electronic carb (which should have a throttle position sensor on it).

There were also some "dual capacity accelerator pumps" on several years of QJets back then. Seems like the "added capacity" was used via some sort of electric switch for cold start driveability situations. It takes a different pump plunger than the regular QJet accel pump, if I recall correctly.

If it's been that way for a good while, you might need to take the air horn (top of the carb off, remembering to "deal with" the roll pin that holds the accel pump pivot rod in the correct manner). You can buy a complete carb kit or possibly still get the correct air horn gasket by itself via GMParts. There is a plastic retainer that keeps the power piston in its bore. It should move freely up and down. If not, then some carb cleaner should do the trick AND make sure the spring that should be under it is still there and in one piece.

If it is an electronic metering rod carb, there will be a solenoid that runs the metering rods up and down instead of the power piston working against spring/vacuum pressures. When they fail, you'll probably see some little bits of orange silicone-looking items in the float bowl. They replace as an assembly.

As for the secondaries, there's a plastic cam that is on the secondary air valve shaft, that raises the metering rods for the secondaries as they open. If it's worn, the metering rods don't move upward (richer) as the secondary air valves open. A somewhat common thing that you might find in the aftermarket carb parts sources or the GM Parts database (some years list it and others don't, but they all "fit").

The vacuum breaks on the QJ have several functions, other than just opening the choke butterfly. The front one also has a small bleed hole in the supply tube that delays/modulates the opening rate of the secondaries, in addition to the air valve spring tension adjustment. The secondary vac break could have several assist functions. I think they are usually an additional way to get the choke off quicker for better cold start emissions and such, but it could vary from year to year and carline to carline.

Also be sure to check the various TVS (thermal vacuum switches) on the engine. If they malfunction or let vac get to where it's supposed to be when it's not supposed to be there, it could "unbalance" things.

The other thing to consider is that even that "light" car could approach 3800 lbs with a passenger or two. Add in the typically 2.41 rear axle ratio (even with the small diameter tires that came on them) and the low stall "tight" torque converters from back then, and it's not a very "performance oriented" setup. But if what power is there is "responsive power", that can help general driveability feel more than raw power would (by observation). I concur that it should run pretty decent, but it's not a "hot rod" in the classic sense of the word.

Just some thoughts,

NTX5467

[3972plymdodge]

Wow----some great thoughts.

Just the kind of info I was looking for.

I have a Chilton's for Buicks of those years, but it is almost worthless as far as giving real useful information. And the pictures are soo blurry.

Are the factory service manuals for Buicks much better---assuming I can find one?

Again ---thanks.

[3972plymdodge]

This carb must be mostly electronic. Got wires going into it in 3 places. Into the choke, into near where the accelerator pump is and also on the other side of the float chamber area too.

I'm not really looking for hot rod acceleration---just more than what I got--which is pitiful--not really all that safe since I need a country mile to merge into fast traffic. My old 1939 Plymouth could accelerate twice as fast as this Buick.

Been driving it this way for 5 years now and am sort of used to it. Gets good gas mileage so am happy about that part. I just have to remember that I am not driving my Dodge Dart with a 318 (which could really fly) or even my old Plymouth. I am driving an 83 Buick Regal with a 4.1 motor and for some reason is slow as molasses on pick up.

Looked into rebuilt carbs on the internet------Runs about 270 to 290 bucks. (when did rebuilt carbs get so expensive?---I remember buying a rebuilt carb for my old Plymouth from Penney's for a lousy $20,--- many years ago of course)

Have a feeling that it is the electronic parts going into the carb that are really causing the problem, which parts I probably wouldn't get with a rebuilt carb anyway---would be expected to reuse my own. So spending close to $300 on a rebuilt carb would probably end up being money thrown away.

Something that puzzles me is that neither the primary nor the secondary vacuum breaks seem to work. See no movement at all on either when goosing the motor. So it would seem that that linkage that goes to nowhere from the secondary vacuum unit wouldn't work anyway even if I could hook the linkage up.

Looking into prices for rebuild kits. Probably aren't 4 or 5 dollars anymore so expect to get sticker shock.

[JohnD1956]

By 1983 a lot of cars had the overdrive transmissions, an R 200 or R 700 I think. Have you tried driving the car in 3rd ( or Drive) and not Overdrive, and then seeing if it may have better pickup? It will cost you some in gas milage and I'm not really sure what to tell you if it does have better pickup this way. But I would definitly inquire about a hot rod shop in your area that has a quality reputation. According to one Buick Performance group that overdrive tranny gets a lot of respect.

Of course, this assumes you have taken the car to a reputable exhaust shop to see if the catalytic converter is flowing sufficiently.

By the way, is that 4.1 a Pontiac motor? or is this the 4.3 Buick Motor? Didn't the 4.1 have a bad reputation in these cars?

JohnD

[3972plymdodge]

According to my owner's manual and to Chilton's the 4.1 is a Buick engine. The 4.3 is an Olds engine and a diesel type.

Mine doesn't have the overdrive, just D, L1 and L2. It does have that clutch type torque converter which engages between 40 and 60 to give direct drive.

Bringing up the cat converter makes me think I may be looking in the wrong direction. (I assume the check engine light would come on with a bad cat, but maybe not). Or maybe the timing needs adjusting--have never checked that.

I just happened to notice recently that dangling linkage to nowhere on the carb and assumed it was carb problems.

But got a good look with a flashlight at what comes out of the accelerator pump------and see 2 separate squirts squirting gas out as good as any car I have ever owned.

And even if the secondary barrels weren't working at all, I would think just the 2 working primary barrels would have more "pep" than this Buick does. (my old 39 Plymouth with a simple 1 barrel carb would leave this Buick in the dust)

This 1983 Regal only had 32,000 original miles on it 5 years ago when I got it. Now has close to 80,000 miles. Has always been super slow on pick up as long as I have owned it. Otherwise has been a good and reliable car---although a little dangerous pulling out into fast moving traffic.

[JohnD1956]

Maybe the Regal is totally different from the full size. My chiltons shows the following for 83 Buicks:

Looking at the 8th digit on the vehicle ID you could have :

an "A" representing a Buick 231 Cu in V6 ( this has a 2 bbl)

a "4" Representing a Buick 252 cu v6 ( this has a 4 BBL)

a "Y" for an Olds 307 V8

or a "n" for an Olds 350 Diesel.

Presumably you have the code 4?

JD

[JohnD1956]

I saw that vacuum break you referred to. The Chiltons does not show enough detail here. But it looks to me that the linkage would go to the back of the choke housing. If your car had a manual choke originally , and it was replaced with an electric one later, you may no longer have this connection.

Personally I'd do this:

Change every single piece of vacuum hose. I know you did not indicate rough running condition but the heat on these cars is enough to dry out the hose and you could still have leaks affecting shift points in the transmission.

Then I'd check the timing. I don't know how to do this but I heard someone say the best way to check the timing is with a vacuum guage. Basically adjust the distributor till you get the best vacuum reading and then back off a little. Then drive and check for knocking or pinging. If need be back off a little more. Of course if you use a light my book shows the timing to be 15 degrees BTC.

Also when is the last time you put plugs in the car? THe chiltons shows the gap at 80. Don't imagine it would take that long to expand that more with use and thus you may be losing some spark intensity.

Also, I'd try driving the car in L2, to see if you have better pickup. This might indicate problems with the tranny modulator valve. Here's another thought though.

Have you listened to the exhaust? By this I mean have you been outside the car while someone takes off with their foot to the floor? If you have you may have heard a whoshing sound, which I could describe as a massive air leak. Or a hissing sound. If so, do the catalytic converter. It really isn't that much but that sound is evidence the internals are disintegrating and pushing the innards into the muffler, clogging that. Blocked exhaust will slow you down.

By the way, try not to go for a universal one. These seem to be very smelly for a long time. OEM will cost a bit more but less than the cost of three car payments.

Of course if nothing else helps drop a 68- 72 Buick 350 in there. That'll liven things up a bit.

John D

[3972plymdodge]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Maybe the Regal is totally different from the full size. My chiltons shows the following for 83 Buicks:

Looking at the 8th digit on the vehicle ID you could have :

an "A" representing a Buick 231 Cu in V6 ( this has a 2 bbl)

a "4" Representing a Buick 252 cu v6 ( this has a 4 BBL)

a "Y" for an Olds 307 V8

The 8th digit is a "4". 252 cu in. or 4.1 Buick engine

The 8th digit is a "4". --------252 cu inch or 4.1 liter.

or a "n" for an Olds 350 Diesel.

Presumably you have the code 4?

JD </div></div>

[3972plymdodge]

Yes ---the 8th digit is a "4".

352 cu in. or 4.1 liter Buick engine. With Rochester quadrajet carb.

[3972plymdodge]

John D--

Thanks for all the good advice.

I did replace spark plugs when I first got the car 5 years and almost 50,000 miles ago. Didn't make any difference back then on acceleration, but I know I do need to replace them again. I remember it wasn't that easy a job to get to a couple of the cylinders, but was doable.

The vacuum lines are surprisingly lively and flexible after all these years. However I know I must have some type of at least slight vacuum leak, because the vacuum operated AC/heater doors are super slow to change position from the default position.---takes a few miles of driving before they change position all the way.

There is one very obvious source of loss of vacuum which I just recently noticed and not sure how to correct it. The metal inserts into the carb that the vacuum lines hook to are both loose as a goose--can just pull them right out. I assume they were originally soldered into the carb.

Any suggestions on how to give them a good seal short of resoldering? Any type of glue you might recommend---that could handle heat and gasoline?

Thank you all for all this helpful info.

PS---Any recommendations out there as to what brand spark plugs to buy? I have heard that Champion spark plugs are lousy---and I have used that brand many times over the years. Not sure what I put in last time--might have been AC Delco. Replacing spark plugs on the Buick is a difficult enough job that I don't mind paying more for an excellent performing spark plug. Is a platinum plug worth the extra cost?

[JohnD1956]

Can you pull them out while the engine is running? since there is vacuum on these they may hold tight while the engine is running anyway. Still, I would pull them out and bring them to a reliable auto parts store. That would be a NAPA in my neighborhood. They probably have new fittings that will take up that slack.I tend to doubt these were ever soldered in. I'm sure they were just pressed into place.

Here's another thought.

If you do have vacuum loss that could definitely impact the transmission modulator valve. But given the car's age and realtively low milage, I'd consider a tranny fluid change WITH a new modulator valve at the same time.

These are simple to change although I do not know if the tranny would leak fluid on that style set up. I know on front wheel drive tranny's they do not leak out, but the valve is much higher on the tranny casing. Anyway, if you try this yourself, the last one I did had not internal connection. it was all external. Apparently the valve is a push rod that is actuated by the amount of vacuum. There was one bolt holding a clamp ( like a distributor clamp) and the vacuum line. Naturally while under there you ought to change that flexible piece of vacuum like too.

Good luck. Let us know how you make out.

Jd

[NTX5467]

If you only have "3" forward gears, then it's most probably the THM200 trans. I don't think it has a vac modulator as other GM automatics do, as it was pretty much a "basic" trans in design. I could be wrong on the modulator issue, though. Low gear should be something like 2.75 instead of 2.52 in the THM 350.

The a/c doors should work much faster than you describe. Other than the vac selector valve on the a/c control in the instrument panel, the vac source would be the reservoir can under the hood, usually a spherical unit. From there, the next item in line could be a check valve near the power brake booster, where the a/c vac source tees off of the vac check valve going to the cruise control. Kind of a funny looking item, but also prone to cracking where the a/c line hooks on. Of course, you could always find a good manifold vacuum source nearer the manifold, yet the use of the check valve in the source line could help with the generally low manifold vac levels during acceleration periods.

The tubes in the carb base that the rubber lines hook to should be tight in their bores. They were always pressed in, but using some epoxy to hold them in might be a good thing to do.

Putting the trans in "2" for normal driving might not help anything as it will not change anything other than not going into 3rd gear. One thing you might consider is possibly adjusting the trans linkage at the carb for a little more preload in the adjustment. That would basically tell the trans that there is more throttle in the motor than there actually is, so that it would delay the upshifts a little bit.

If the trans upshifts too soon, the engine rpm will drop too low in the next gear. Hence, more throttle and less acceleration and poor fuel economy. To check this out, manually shift the trans from 1st to 2nd to 3rd about 5mph higher than it normally would by itself. If you can use less throttle input to run faster, this minor adjustment might be all that's needed, other than the attention to normal maintenance items. A little tweaking usually will not hurt anything, but don't vary much from the factory adjustment in this respect. The adjustment is usually in the block on the cable where it goes into the mounting bracket.

As for spark plugs, you could do a lot worse than use some OEM spec ACDelco plugs of the original "normal" type. Platinums/Iridiums (the current production 3800s come with Iridium ACDelcos in them) will last longer and cost not that much more money. Your judgment call. Be sure to check the condition of the other ignition items too.

In some respects, you might be better off finding a competent entity to rebuild the carb you have. Buying a "generic" reman unit is just that--generic. Getting one that is an exact replacement for your existing carb is the best way to do things, but is usually more costly. None of these are going to be "inexpensive", though.

Even with the restrictors in their vac hose connection tubes, the vac breaks on the carb should pull in as the engine is started and stay there. In some cases, you can override them by pulling them back out, but they should still return to their "with vacuum" position. Perhaps the internal diaphrams are having age-related issues?

Maybe when you follow all of these "details" to their completion, things will be a little bit better. If not, then you at least know what's been changed and when.

Enjoy!

NTX5467

[3972plymdodge]

Thanks for all the great info and advice from all who have posted.