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Awhile back I bought a non running 89 Buick wagon with an olds 307 and CCC carburetor. It hadn’t run in 20 years said the seller. A new ignition module and fuel pump cured my lack of spark and fuel. Unfortunately there was a fuel leak somewhere at the carburetor after the fuel pump replacement and it caught fire when a backfire occurred. I was pretty discouraged and hadn’t worked on it for awhile up until recently. I spliced in a wiring harness from a donor and ran new vacuum lines. I decided to start from scratch with the carburetor and bought a new same model carburetor from an apparent running car on eBay. After installing the carburetor I can’t get it to idle at a reasonable rpm without stalling. It won’t start without pressing the throttle to almost WOT. But runs decent while giving throttle. I haven’t been able to properly set the timing as it won’t idle low enough but I’m confident it’s in the ballpark.
Things I have done;
Rebuilt the carburetor (and cleaned about 3 times since then), blocked off the EGR, changed intake manifold gasket, verified the hot air choke is working, checked for vacuum leaks using two cans of starting fluid and a smoke machine. Verified the MCS and TPS are working (dwell was around 30), replaced O2 sensor, and adjusted mixture screws and air bleed every which way(returning to bench settings after) but doesn’t make a difference.
If I hold my hand over the choke it halfway idles but not well. If I unplug a vacuum line and make a deliberate leak it doesn’t have an effect. Everything tells me there’s a vacuum leak somewhere but I have searched for a three days now to no avail. The only thing I noticed with the smoke machine was some slight smoke around the secondary air valve linkage on the passenger side but I wasn’t thinking that will do too much so far from the base plate. Any feedback really would be appreciated!
Start with a compression test and timing chain evaluation. The backfire that started may have been chain related. I understand that it will run to some degree but i"d check them especially since you have checked so much else.
Confirm the firing order is correct at 1-8-4-3-6-5-7-2.
How many miles? Looks as though the car is ""all there".
Last edited by Sugar Bear; June 15th, 2024 at 05:55 AM.
If you don't have a factory Chassis Service Manual, get one. The CCC system has a very involved adjustment procedure that is completely detailed in the CSM. If you don't follow this process exactly, the car will never run right. Turning the idle mixture screws without using the correct dwell meter connection to monitor the duty cycle of the mixture control solenoid will make the system apoplectic. There are no shortcuts here. Of course, before doing that, you MUST ensure that every single vacuum line is in good shape and connected correctly. Take shortcuts at your own risk.
June 14th, 2024, 10:57 PM
