Hesitation on take off and not much acceleration sometimes

It's hard to explain but i'll try. when trying to take off from a standing start like a light or stop sign i'll get a hesitation in throttle like it's bogging or choking itself. i'm pretty sure it's carb related as my dad and I replaced just the accelerator pump plunger and that has helped a tad with the hesitation however, I find the car seems to have slow acceleration half the time like if I go to punch it to pass a truck or something.
now i'm not expecting race car speeds and LT1 response out of a stock 305 but I feel like there should be more response and a bit more acceleration.

we've changed the timing chain and gears in the car to a double roller set and I did the plugs leads cap and rotor as well, and my dad fould me a delco performance coil (I think it's performance) from an estate sale for $20 so I don't think it's any of that.
I have been thinking of trying to convert the fuel system over to a newer throttle body system from a 90's 305, my buddy said it might not be too hard and it would give the car more reliability and such.

so, is there any way to improve the carb for better response or should I be thinking more on trying the throttle body idea?

it also doesn't help I make $11.50 an hour at work and have a kid at home so it's also about the cost of each.

 

id remove the block off plugs for the air fuel mixture screws and richen it up a little , also bump the timing up till she spark knocks then back it off from there

 

Actually, if it's a C3 computer system, you really need to make sure it's working right, and then make sure the carb doesn't have any problems. making sure the idle wells don't leak is a must; pull your plugs to read them. They should be light to medium tan. Black is either leaking idle wells or a computer problem. Based on the bog and low accel, I'd guess the idle wells leak, and combined with the accel pump shot, it makes the engine too rich on throttle opening. But that's just a guess.

 

probably signs of a carb rebuild right? is it easy enough to rebuild on your own or is it something that should only be done by a mechanic?

 

They can be rebuilt if you really, actually, have mad skills to do it. The trick is having the skills, tools and the scantool to properly dial it in. Also, knowing how to address the problems inherent in them is necessary. Or, you could buy a replacement spreadbore carb and remove the computer controls, but you'd also have to replace the distributor and dial that in. There are a few ways to take care of this, but the first step is to diagnose the problem, otherwise you're just throwing parts at it.

 

The first question is, what engine do you really have? By 1986, nearly all the B-body wagons got the Olds 307, not the Chevy 305. Check the eighth character of the VIN. If it's a "Y", that's the Olds motor.

The CCC system MUST be tuned and adjusted EXACTLY as described in the Chassis Service Manual. You must also verify that there are no leaks or cracks in any of the miles of vacuum hoses. There are MANY failure modes in the CCC system that will not set a Check Engine light code, as these cars have very simplistic computer systems based on 1970s technology.

 

I agree that the 1st step is to check for Vacuum leaks (I usually just replace all the vacuum lines as they are now 30 years old) Also check around the carb bas gasket and be carful if you tighten the two long bots at the front of the carb that hold it to the intake manifold. Do not over tighten those 2 bolts!!!! If you do you can cause the top plate of the Carb to warp. And then it would have to be replaced.
Also Q-jets can develope leaks around the primary and secondary throttle shafts. A quick check for vacuum leaks is to cover the air inlet of the carb momentarily at idle. If the rpms increase that usually indicates the engine is getting air from a source other than the carb. Good Luck, Post some pictures and keep us informed.

 

I have the 305 not the 307 olds, funny enough my first 86 had the 305 as well, but the 87 I have has the 307. I will check for vacuum leaks as cammerjeff said by plugging the air intake for the carb at idle.

 

So the problem is intermittent?
It does get up and go some of the time?
Would you call it bogging? Any sputtering, backfire or missing?
Can you scan this older type of computer system for codes?

 

I don't have a scanner for this system and it's like a bogging you could say, no backfiring, missing, or sputtering. and yes, it's like the bogging happens intermittently and it acts worse if I have say the A/C on pulling on the motor. but half to just over half of the time the acceleration is slow, almost feels like i'm pulling a trailer if that makes any sense.

 

an update for you guys, I got the chance to check for vacuum leaks as you described and it indeed did go up in revs when the air intake and heat riser opening were plugged so i'm going to inspect the vacuum lines and do replacing as I inspect.

 

Checking for vacuum is an excellent idea, also check for proper fuel pressure and volume. If you have an inline fuel pressure gauge, you can temporarily install it between the fuel pump and the carb, you should get 5-7 lbs of pressure if you are running a mechanical fuel pump. As for volume, disconnect the fuel line from the carb and have it drain into a pitcher or two liter bottle. Start the car (it should run off the fuel in the carb bowls) and let it run for about 30 seconds, you should get about a liter or so of fuel in the bottle (very non-scientific). Good luck.

 

Not sure what your carb looks like but I had the exact same issue with my 368MEL. It was an accelerator pump cup. The AP gives you a quick shot of fuel when you step on it. If the cup is shot that would show up in your symptoms. BTW I had mine replaced by a supposed pro and he put it in upside down, it caused more heartburn for anther 6 months.

 

How much vacuum are you pulling at idle? Have you checked your timing? Have you confirmed your centrifigul advance is working (rev with timing light on)? Have you verified you are getting a shot of gas when you hit the accelerator. Plugs and wires good?

I assume from your original post that the bog came on suddenly, or changed as a result of a change you made (i.e. it isn't an ongoing issue, or came with the car)? If so, start where you made your last change, or look for visible or measureable signs of a failure (no gas, low vacuum, low fuel pressure, timing suddenly off, etc.)

I would highly recommend establishing baseline values for timing and vacuum before you make any further changes. Make one change at a time and note the effect it has on performance, idle, vacuum and timing. Follow a logical methodology rather than just replacing parts. It will get you to your solution quicker and for less money.

Good luck, and please post the results of the changes you make.

 

I purchased an 84 Cutlass H/O about 6 weeks ago and was having some Q-jet problems. It was running rich and idling poorly. I swapped on another Q-jet I had. It ran better, but still running rich with hesitation off idle. I tore apart all the Q-jets I had for jets and rods to lean it out as much as possible, but still ran rich and fuel would seep out the accelerator plunger hole. I then checked the float level. It was OK, but I adjusted it down further in case and still it was rich with hesitation and slight stumble off idle. The only thing left to check was the float valve itself. Nothing was keeping it from closing. In comparing it to one from another Q-jet, I noticed the rubber tip was a little harder and more importantly, the valve body did not have slits in the side for gas to flow out. Gas could only go out the top. There was an immediate improvement when I swapped the valves. No more seepage, no hesitation, and no heavy gas fumes in the exhaust. BTW, none of these carbs are CCC Q-jets.

Some recommendations regarding Q-jets:

• Don't remove the baffle over the valve in the fuel bowl.
• The primary throttle shaft is where wear is most likely to be a problem. If you can wiggle it enough to see play at the throttle cable/linkage side, it probably is creating a vacuum leak. You can get the throttle plate bushed. If you try to do it yourself, removing the screws for the butterflies is a pain because they are staked to hold them in. You have to grind the ends off or some will break off in the shaft.
• Don't go bending any of the linkages to get the butterflies to open more.
• Don't disconnect or bend the linkage for the vacuum break on the secondary.