1989 307 Olds CCC vacuum diagram map

Hi.




I recently explored the engine bay of my stock (as far as I can tell) 1989 Buick LeSabre wagon (68k miles) with a mind to map out the vacuum lines along with identifying the components on the diagram itself. I also replaced several visibly damaged hoses and documented the entire adventure here. I realize I completely misidentified or ignored the A.I.R. pump system, but I did learn something!

I would greatly appreciate anyone who knows more about this engine/carb combo to help me fill in components I missed or I just plain got wrong and post critical feedback or comments here; I'll absolutely update it. I haven't been able to find any similar mapping/identification resource or pictures on the web, so I wanted to put this out there for other DIY'ers.

After I played around under the hood, it does feel like the throttle is more responsive (for a 4300 lb beast), but it could be just my imagination or wishful thinking. A couple of my upcoming jobs are going to be a trans oil pan gasket/fluid change (200-4R), and a complete tune-up. I definitely want to use the right ATF. It also has a small oil drip leak that seems to be coming from the passenger side rear of the engine. Possibly the valve cover above, or oil pan below. Maybe both.

Any tips going forward?

 

I can ID most of the items listed in the diagram; for example, the THERMAC is the air cleaner snorkel heat door control, which, of course, sets when the engine's cold to draw heated air off the exhaust manifold. What I can't ID, I can look up. What items do you not recognize? As for leaks, the tinware will begin leaking just about at anytime; I would suggest checking to ensure that all bolts have their individual load spreaders on the valve covers and the two oil pan rail reinforcements, resnugging all the valve cover and oil pan bolts to spec (84-144 Lb-Inch), and verifying the PCV valve is good and has full manifold vacuum with no vacuum leaks or a collapsing hose.

 

One thing is apparent to me in the diagram, and that's the MAP (Manifold absolute pressure) sensor does not have a sole source of manifold vacuum. It shares with the THERMAC and the CCV (canister control valve, or fuel vapor canister valve), so ensure none of the vacuum lines are compromised, or the MAP sensor will read incorrectly.

 

Thanks for the info! Especially about the THERMAC. I haven't identified the EAS or EAC, or even the MAP sensor itself. I feel like I photographed one of either the EAS or EAC, but I couldn't identify it in my blog post.

I can hope that just snugging the bolts up all around to spec will fix the leaks what ail me.

I have already replaced the PCV for good measure, but I haven't done a vacuum test yet. I think I replaced all the lines going to the CCV while I was under the hood, but I'll check since I don't remember the MAP sensor.

When I bought the car there was (what even an amateur would consider) an unusual amount of oil residue in the air cleaner and around the PCV. I also replaced the crankcase breather element because it was extremely dirty as well. I know improper vacuum and pressure can cause that, which is why I replaced the breather and PCV, but is there something else I'm missing?

 

On the oil in the air cleaner: replacing the PCV, the filter, and verifying there's good vacuum (no carbon buildup in the carb throttle body passage) should alleviate that. The EAS and EAC I've confirmed are with the A.I.R. (Air Injection Reaction) system, as one valve directs air to the heads or converter, and the other dumps air on deceleration to prevent backfiring, so look at the air delivery pipes and you'll see the valves, which each one will also have a two-wire connector from the computer. The MAP sensor is a black plastic unit that is connected to a vacuum line underneath, and has a three-wire connector to the computer.

It's bolted to the right inner fender liner. On your car, if you look at your underhood pic, you can see it, right behind the coolant bottle and right next to the A/C pipe going to the accumulator; the connector is green.

 

I've had four of these cars now. All I can say is that by the 1980s, GM was doing a VERY poor job in documenting this stuff. You need the underhood decal AND the Chassis Service Manual AND a lot of time scratching your head (or whatever body part) to figure this out. The diagrams are poor cartoons. The device labels are inconsistent among the factory documents. There are no diagrams that show the cruise and A/C vac lines and canisters, despite the fact that this changes the diagram and most of these cars came with those options.

EAS and EAC are the vac feeds to the A.I.R. diverter and switching actuators on the passenger side of the engine. Not a big deal - these are just vacuum feeds to the control solenoids and the solenoids feed the actual diaphragms.

 

Exactly why I wanted to get under there and document mine. I wasn't able to find any specific resources online, so it might help someone else with one of the 307s still running out there. I can definitely agree that the shop manual isn't as helpful as I had originally hoped, but it's great for most things.

 

Yeah, back then, the car co.panies weren't so forthcoming, which is why the EPA mandated they come clean with everything for OBD II. Now, the car companies are trying to get that quashed so that cars bave to come to the dealers only.

 

Huh? GM was perfectly "forthcoming". There wasn't a lot of technology in the CCC system. The problem was simply cost cutting on the service manual development process. The 1960s vintage manuals were far better detailed and typically showed the various option configurations. The 1980s vintage manuals just don't have that level of detail. They don't provide a vacuum hose diagram that includes all the optional equipment, for example.

 

When folks complain about the vacuum lines on the Olds 307 boxies....remember this.

 

Yup. It's cars like those that make you appreciate newer computer controlled vehicles with electromechanical actuators.

 

While sometimes I may not agree with you, Joe, I definitely agree with you there. One of the major engineering shifts in automobiles is the use of the computer to drive the items that make it run, hold down its emissions and let you know what area to look when there's a problem.

 

I looked at that diagram and immediately started sweating.

At least the one looks like a transit map or something, but that Honda would give even Mario and Luigi nightmares...

 

Hahahahaha!

 

Damn, Rube Goldberg would be proud