olds 307 to olds 350 swap.

...not to keep this thread off course, I will say I would have had a similar temptation as BrownWoodyBuick. I too have an '87 307 engine that is severely sluggish and hesitates from a stand-still. Mine isn't burning oil, but the sluggishness is annoying. "Cold" morning starts require several pumps of the accelerator while cranking too, if she hasn't been driven the day before. I never had this much trouble with my previous 400 or 350. Anyway, BrownWoodyBuick, you're not alone.

 

The CCC system works very well IF it is properly tuned and maintained. Unfortunately, few people have the skills or patience to do that and usually resort to the far more expensive engine swap. Keeping the factory equipment properly tuned will always be less expensive.

Also, be aware that this ISN'T a fuel injected motor. You DO have to pump the accelerator pedal BEFORE cranking (NOT during) to set the choke and squirt some fuel in the intake. That's the way carbs work. Pumping DURING cranking is not what you want to do. Unfortunately, the ethanol-laden cat piss that passes for gasoline today evaporates quickly from the float bowl and sometimes cranking is required to pump fuel back into the carb, especially if the car has not run in a few days. This isn't the fault of the 307.

 

Joe,

Thanks SO much for educating me on this. Like I mentioned above, I never had this issue with my 400 nor 350, but then again those engines were from a prior generation than my current '87. Setting the choke with just one pump prior to cranking ALWAYS got those cars started on first crank. Naturally, I attributed my current challenges to the 307. I'm sensing that going forward I should expect to have to crank more than once or twice to get the wagon started if it sits for more than a day or two and to refrain from pumping during cranking. Question though: Once setting the choke, is there any point to pumping the accelerator more than once prior to cranking?

Matt

 

Only if it's really cold outside. One pump usually suffices down to, say, 20* F. above, then below that, two pumps and hold the throttle 1/3rd open as you begin cranking and release when the engine has caught.

 

Another thing to consider is that the plugs in the bottom of the carb wells corrode, allowing fuel to drip out of the wells when the car is sitting. Causes the same problem and calls for a carb rebuild if that's the problem.

 

Andrew, OldFox, thank you! I can't wait for the wagon to return home from the carb shop this weekend.

 

Pressing the pedal once sets the choke and squirts fuel into the intake from the accelerator pump. Subsequent pressing of the pedal squirts more fuel for a richer mixture. This can help overcome a choke that isn't closing properly or vacuum leaks.

Your starting issues are attributable to one of two sources, neither directly the fault of the Olds 307. The first is today's ethanol loaded gas. It does evaporate from the float bowl more quickly, especially if the car isn't driven daily. I have this problem with my 1962 F-85 wagon as well as with my 307-powered cars. In addition, ethanol doesn't have the same energy density as gasoline, so more is often needed on a cold start.

Second is the emissions equipment on the 307. The CCC system was the last carbureted motor sold in a production car by GM. The ECU is rudimentary and only controls a limited number of functions. The majority of the functions are still mechanically operated by vacuum and bimetallic strip. A small crack or other leak in any of the miles of vacuum hoses under the hood can cause a problem. At a minimum, the resulting vacuum leak will require additional pumps to start the car. When was the last time you replaced all those hoses?

 

That is a relief, thanks Joe. I have been having intermittent feelings of buyer's remorse on this wagon, being my first of the '80's era. My prior two cars were much simpler, despite being fully loaded with options.

I've only had the car a couple of months, so no hoses have been replaced yet. Is testing for a leak something I can do (I'm not a mechanic)? Also, remind me what "CCC" stands for? Sorry for being so ignorant and thanks for being patient...I'm learning a lot here!

 

CCC stands for Computer Command Control, which is GM's brand name for the computer-controlled carb and distributor system. The computer is pretty limited in capability and really only controls the air/fuel mixture on the primary side of the carb and the distributor timing. It also controls some secondary functions like various parts of the emission control system, the idle kicker, and disables the A/C compressor clutch at wide open throttle. Most of the functions are vacuum actuated and those miles of vacuum line are all potential leak points. The only way to check for leaks is by careful visual inspection, and at that point you might as well just replace them. I do that proactively about every five years. Also be aware that some of the vacuum-operated devices themselves can leak, such as the A.I.R. diverter valves. These vacuum-actuated devices are not connected directly to the computer and failures will not set an error code, but can result in poor performance. Of course, ethanol in the fuel can also deteriorate carb parts like the float and accelerator pump, causing additional problems.

 

Thanks again Joe. Aside from the poor acceleration performance, I do have one other indicator of a vacuum leak; which I wrote about in a different thread here. One day while cruising on the freeway I came upon a long steep hill. I found myself having to nearly floor the accelerator just to maintain my 65 mph (no passengers, no cargo and I weigh only 155 lbs). While doing this, I noticed my A/C cut out...or so I thought. Turns out what is really happening is the air flow gets diverted to the floor and windshield because the vacuum leak causes the ventilation system to move to its fail position. As soon as I crested the hill and started letting off the accelerator, all was back to normal. Sounds like I have a vacuum leak to find.

How does one go about checking/testing the CCC to determine if IT is my problem?

Thanks again Joe!!

 

Has this thread been sufficiently hijacked yet???

 

This myth will never die.

The only Qjets that have ever had this problem are the 1966-67 carbs with the sheet metal well plugs. Every Qjet since the 1968 model year has used very thick spun-in aluminum plugs there. The carb body would corrode before these plugs. The do NOT leak. Unfortunately, ever since Doug Roe wrote about the leaking well plugs in his Qjet book, everyone thinks this is a real problem. You'll note that if you really read his book, the photo he shows of the repair to the plugs is of an early carb with the sheet metal plugs.

 

There are a number of checks and adjustments, and they must be performed EXACTLY as specified in the factory Chassis Service Manual. If you don't have one, get one. Ironically, the Buick manuals are hard to find and expensive when you do. The Oldsmobile manuals are common and cheap, and the Custom Cruiser is identical to the Buick wagon except for the front sheet metal and grille.

 

I don't know the guy nor have I read his friggin book. I based my answer on the fact that I was a professional, certified mechanic from 1964 to 2000 and rebuilt 100's of QJets during that time, several of which had the problem and were not 66-67 carbs. Never say never!!

 

I worked for a shop that also specialized in carb rebuilding, and YES, the well plugs seep. I've actually seen it. All we'd do for those, though, is peen the metal around the plugs, then seal with good ol' JB Weld. We also did the same thing on Carter Thermoquads.