packardbob

Well, I recently purchased an 83 Buick LeSabre from the neighbor lady accross the street. I've been around the car my entire life as it has moved from neighbor to neighbor. Anyway, her husband passed away in 1991 and the car sat in the garage since as she never has obtained a license to drive an automobile. She moved into an apartment and asked if I knew anybody that might be interested in buying a car for $800.00. I said on the spot that I'd buy it. The car is in excellent condition, everything was original and in great shape, all the original warranty papers and window sticker were in the glove box neatly preserved. The engine of course was a 307 and I appreciated it dearly. Well, the 307 gave me what it had left, but I decided on moving up to something bigger after the 307 crapped out. So I swapped in an Olds 350 and have been very pleased driving on the hilly highways around here. It doesn't shift out of overdrive anymore going up hills. This is something so impressive that I demonstrated it to a friend after I ridiculed his Honda for shifting down two gears to get up the same hill. He still doesn't believe me that the secondaries opening up can feel like the transmission shifting down. Highway pleasure aside, I'm still chasing bugs out of it and have been since day one (its Buick is showing, hehe). I took it to the retired service dept. manager from the GM dealership we had here years ago and I left him rather depressed as all he could tell me after 3 hours was that he didn't know what to tell me. Undeterred I took it to another old GM mechanic and he told me the source of the crappy idle is the duty cycle is running lean. He couldn't tell me why though. That is why I'm here. I'm hoping to get some good advice on how to fix my problems and perhaps help somebody else out as well.

csstrux

Welcome.

Oldsguy

First, welcome to CO we are glad you are with us. Second, it could be the carburetor causing the poor idle but you may also have a vacuum leak or it could be your ignition. Tell us some more about it, any maintenance you have done recently etc.

Lady72nRob71

Welcome to the site!
Sounds like a neat combination you have!
Please tell us more on the car and problems you have. When adding the 350, did you retain the computer controls? If so, then there is a lot to check and tune. It is do-able though.

citcapp

Welcome to the site

packardbob

Thanks for the encouraging responses so early. I'll start out with everything I've done so far. Like I already said, I took the 307 and stuck it in the garage and put in the 350. Everything was a direct bolt on and most everything was kept. The AIR system was retained although there is a "test pipe" where the cat used to be. Emmisions nonesense is a thing we don't need to worry about around here. The water pump was replaced for good measure as was the starter, the O2 sensor, plugs, plug wires cap and rotor as well. The CCC also remained as I heard it didn't really hurt performance at all, except when a sensor goes bad it can be a bear figuring out what in the crap is going on. The vacuum hoses were carefully replaced one by one with fresh hoses so I'm quite sure it isn't a vacuum leak. The carb is also a hold over from the 307. It runs great on the highway, but the idle stinks. It's rough and sounds horrible. Here is what has been tried with the carb. After we set the timing using vacuum rather than a timing light, he set about trying to smooth the idle out using the idle mixture screws. Didn't work, backed them out most of the way and said if he took them out any farther they might fall out, so he adjusted the fast idle and choke while I went to lunch. When I came back, he said he didn't know what to tell me. This one baffled him. Anyway the other GM mechanic he recommended might as well have said the same thing. He had the car for 2 hours and told me to replace the EGR valve, he wasn't sure it would fix it, but the one on there was bad. So I replaced it and here I am with a car that idles like crap still. So, feel free to ask any questions at all that might help out.
Thanks

Allan R

83 Lesabre was a nice car. Really cushy ride with plenty of plastic parts. My 83 Regency had a 307 also. Good reliable starter and not bad on gas. But it was a dog for pulling a trailer, especially on hills. The 200R4 didn't really help out a lot. I expect that's what you have in your car too. An Olds 350 transplant?? Oh heck, why not. Rocket 350's are proven performers with plenty of power and torque for a car the size of a LeSabre. Should have done this with my 98, but gas prices were starting to get really stupid.

What year 350 did you get?

If it idles like crap it might be the carb. I would suggest that it might sucking air from somewhere. Is your carb tightened right down (1/2 inch bolts - snug em right down). You might also want to check and see if your fuel filter needs replacing - one of the cheapest fixes to most fuel supply problems. Most guys I know don't use the EGR on the 350, they block it off with a metal plate. If you have a new one and it's working ok, might as well keep it.

You indicate the car has plenty of power when its flying down the road - WAHOO - the comparison between a 307 and 350?? If it's not idleing or running properly you might get even BETTER performance at highway speed your problem's resolved. That's what Oldsmobiles do really well (in addition to being just awesome looking cars).

Don't get me wrong on this point because I'm not a mechanic, but here goes. The 307 4bbl you took off the 307 may be your problem. If the mechanics with "experience" said that they couldn't set the idle using the 2 set screws and that it needed to run richer...you might want to go to the boneyard and pick up a carb from an Olds 350. Rebuild it or have it rebuilt at a shop and plunk it on. If you need the settings for idle speed you can get them here on the tech section or from members.

I am not 100% convinced that any 4bbl will work well on any engine. Let's see what anyone else has to offer. That's my 2 cents worth.

FYI - I changed out my Olds 350 from a 2bbl to a 4bbl. A bit of heavy lifting but worth it. The carb is an easy install and easy to set. Hope your problem gets resolved.

packardbob

Yeah, the LeSabre does have alot of plastic on it, but it's all in really good condition. I've put my elbow through the plastic fan shroud a few times but I found a new one from an 85 Lesabre at the junkyard. The 98 Regency is a nice car (C-Body right?), my grandfather had an 83 with an Olds 350 Diesel in it. It was a bigger turd than the 307 but it got excellent mileage on the highway for a car that big and had over 340,000 miles on it when it was junked. He was a hardcore Olds fan and is most likely the reason I'm interested as well. In the movie "A Christmas Story" he announces that "some kids dads were Jewish and others Catholics, my dad was an Oldsmobile man" that line was spot on my grandfather.

Anyway, to the car, I thought the same thing about the 307 carb not being set up to deliver enough fuel to the 350, but I was reassured by both mechanics that the computer should be able to compensate for the extra 43 inches without a problem. I am beginning to question their judgement. As for the fuel filter, its new, and the carb was tightened down to spec with a torque wrench so I wouldn't over tighten the bolts while still getting them tight enough. The comparison was between the 307, the 350 and my friends 3.5L honda. Both the 307 and his Honda had to shift down (his shifted down twice) to get up the same hill, on the 350, the secondaries open and the car is accelerating going up the hill without having to shift down.

Thanks

82 Grocery Getter

Welcome, packardbob!

Lady72nRob71

Wouldnt a simple rejetting help the carb? (I know it sounds too easy, so this probably is not the problem)...

Was the 350 running well before the transplant?
What distributor are you using?
I am at a loss...

packardbob

I was hoping to not have to open the carb up. I put a rebuild kit on the carb while the 307 was still running and honestly I had never been more frustrated in my life, my fingers are way too big for those dinky little parts, but by golly it sure ran great when I was done. I'm leaning towards rejetting the carb and checking out some other things while the carb is apart, but I'm in the middle of moving and can't seem to find the instructions that came with the rebuild kit that tells the destructor how everything should be measuring and in what order to do it. I have found some info here in the Tech section about primary metering rod size, secondary metering rod size...but I guess I'll have to wait to crack the carb open to see whats in it and richen it up bit by bit till its running better. The dizzy is off the 307, it's been ohmed out several times to see if it's screwed up and it seems to pass every time so I've ruled that part out for the time being as being the culprit for the rough idle.
Thanks

packardbob

Well, I worked on the carb all day long and came up empty handed, the car doesn't idle at all anymore. I noticed the idle air bleed valve was screwed ALL the way in, so I backed it out four full turns, roughly where it should be right? It didn't like that at all. The Idle Mixture screws were still three full turns out, turning those either way doesn't do squat to improve the idle quality at all, so I left them at three. I looked at the jets while I was in the carb and they were marked 76 which is pretty rich as I understand. I'm starting to wonder if the computer is whats screwing the idle up. None of the physical adjustments seem to work for beans so I think that could be whats up. I was told I would need a new PROM for the ECM but then again I was told I wouldn't need one. Since a new one would cost money, I went with the old one. Any suggestions?

Mr Big

My dad bought an 85 Lesabre new, it was a nice car, comfortible, with those red "Lazyboy" velour seats. But it was an enimic performer, and fouled the plugs every couple of oil changes. It was the most underpowered vehicle I've ever driven...approximately 4000lbs and maybe 150hp on a good day. Sick, sick sick!

Lady72nRob71

I have heard of others going from a 307 to 350 with minimal mods, so the stock PROM should work fine. What do you have as for idle compensation / anti diesel solenoid? Can you screw in the idle speed screw and get it to idle?
The 307 disty should work from what I have heard. Got the vac advance hooked up? Maybe experiment with slight timing adjustments and see what happens.

When you start the car cold, does it run better or worse than hot? When cold, the computer is in open loop and the engine should run fine on its own. If it does not, then the computer can be ruled out.
At 140* or so, it goes into closed loop and if it cannot due to malfunctions, the SES light comes on but it should still run okay. To disable the computer for hot troubleshooting, pull the ECM fuses from the fuse box (there are 2 or 3).

Here is some other info:
http://www.oldspower.com/vb/showthread.php?t=26225

J-(Chicago)

Bob, I have 4 computer controlled carbs here.
2 of them ran great when I pulled them off, and the other 2 were from junkyard motors.
If you would like to give them a try, let me know. I'll let them go for 20 bucks a pop plus shipping. I'm not going to use them. I'm just keeping them around for the spare vacuum pulloffs.
If they can help you out, even better.

packardbob

I did a little experiment after work today and hopefully have found the problem. I unpacked my ALDL connector for my code reader and plugged it in the car and watched for it to go from Open to Closed. Sure enough, at about 135 degrees it went to closed loop, and started running like crap. I would think this would be the computer right? All of the sensors were replaced with new ones and when tested returned nominal values, so it might be the computer.

Thanks J-Chicago, I have two rebuilt QJets here already, one on the car and one I rebuilt plus the salvage yard owner near here has quite a stock of QJets. Thanks for the offer though.

As for the vac on the dizzy, there isn't one, CCC cars are centrifugally advanced, no vac. Which I guess is okay with me as there are already plenty of vac hoses under the hood as it is.

Lady72nRob71

OK, you have narrowed the problem some...
You mentioned replacing all the sensors - which ones and what brands did you use? O2 sensors should only be AC Delco. TPS in the carb would need adjustment after replacement. Does your code reader spell out any trouble codes? The anti diesel solenoid / fast idle control adjustment could be misadjusted, causing the idle speed to drop too low when going into closed loop. This is controlled by the ECM only and enables at about 140*.
I read up on the 86 disty and we are both wrong - there is no centrifugal advace either! There is a secondary backup timing map should the computer fail...

packardbob

The O2 sensor was AC Delco, I found that one out online that Bosch sensors may cause surging, too bad I didn't find that out before I bought the Bosch. As for not being centrifugal, I guess the parts guy at the GM dealership was a boob. Anyway if the computer has failed and the secondary timing map has kicked in, it could explain some of the goofy things the mechanic saw when he was trying to set timing with his timing light. He didn't tell me what his light was telling him, but he had never seen it before. He eventually gave up and set it using vacuum. The TPS is not new, it has been tested with a multimeter and there were not any dark spots in voltage from idle to WOT. There are not any codes stored in the computer, and nothing shows up while it's running.

joe_padavano

Coming into this thread late, so sorry if I ask questions that have already been answered.

The CCC system is highly integrated with the various emissions controls. The fact that you may have removed some and retained others can lead to problems. For example, if the A.I.R. system is not functioning properly, it will continue to blow fresh air at the O2 sensor even when the computer should be in closed loop mode (at which time the A.I.R. system is supposed to be only providing air to the converter). The result of fresh air blowing at the O2 sensor is that the system reads a severe lean condition and richens the mixture control solenoid.

Ultimately, the CCC system works great IF it is properly set up and ALL sensors and actuators are working. Most people (including dealership service departments) have no clue how to adjust these systems properly. The Chassis Service Manual has detailed directions which MUST be followed in order. Simply throwing parts at the car will likely NOT fix it. The CCC system requires someone who pays attention to detail and follows directions to the letter.

packardbob

The only emisions stuff I took off was the cat. The diverter switch on the air pump is working fine, or at least the computer says so, so it's probably not. The line that went to the cat has been muffled but not plugged. I am growing very suspect of the computer and it's output as the computer says the MC Duty Cycle is running between 27 and 38, but the MC wire that sticks out of the wiring harness in front of the carb that my mechanic stuck a dwell meter to is reading between 25 and 6. I've been in contact with the mechanic I had when I was still in school that took first crack at getting it to run well and he told me the MC Duty cycle is running lean at the carb. Honestly I should have seen it then, but I didn't know what input was to the computer. Input seems fine, but output seems not to be what the computer is telling me. I think I'm going to the salvage yard next week sometime and swap out four or five computers out of other 83 buicks to see if I can get one to make the car run better.

joe_padavano

First, the data stream from the ALDL connector can only tell you if the command was sent to the diverter valve. There is no independent feedback monitor to confirm that the valve actually switched or not. Feel free to swap all the computers you want. I'm betting that is not the problem. You can easily check the A.I.R. system by pulling the rubber hose off the check valve on the pipes going to one cylinder head. When the computer goes into closed loop mode, there should be no air at this hose. If there is, the valve is likely bad.

Of course, this is not the only potential problem point.