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1974 L48 4 speed, 31K miles and believed to be accurate per MVD records. Purchased the car in early 06' - engine operation was perfect during all of 06' - actually flawless. Prior to purchase the following related parts were replaced with new parts by the selling dealer: fuel tank, fuel pump, rotor, distributor cap,points, vacuum advance unit. Carb was rebuilt and is the correct Quadrajet P/N for the engine which is numbers matching to the car.
On first start this year after winter storage of 4 month the engine will not hold idle. It will run fine above 1500 rpm and will start fine cold the first time. After it starts the idle speed jumps around and it will die and then either will not restart or is extremely hard to restart.
I have done basic electrical troubleshooting to the ignition system and to the centrifugal advance system - everything appears to me to be normal. I suspected a float issue and put in a new correct configuration float and set it per Lars advice at .375". The carb was spotless inside confirming the dealer claim of a carb. rebuild kit having been installed. The accelerator pump was obviously brand new. I reinstalled the carb with a new gasket - all with no effect.
I am currently suspecting a vacuum leak. All of the vacuum hoses appear good and most appear to be new. Everything is connected as it should be except the vacuum advance electrical switch is bypassed so vacuum hose is direct from vacuum advance to carb. The intake manifold bolts are tight and I have looked at the front and rear where the intake manifold mates to the engine and see no evidence of any mising gasket material. Note: The dealer had removed the intake manifold prior to sale - he gave me the pictures he took during his resoration work.
Looking for ideas of where to go next. Has anyone experienced something like this?
Could it be the EGR valve stuck open/rusted open or perhaps a missing EGR valve gasket? I believe the EGR value is original as there was nothing on the pre-sale repair invoice to say it was replaced.
On first start this year after winter storage of 4 month the engine will not hold idle. It will run fine above 1500 rpm and will start fine cold the first time. After it starts the idle speed jumps around and it will die and then either will not restart or is extremely hard to restart.
I have done basic electrical troubleshooting to the ignition system and to the centrifugal advance system - everything appears to me to be normal. I suspected a float issue and put in a new correct configuration float and set it per Lars advice at .375". The carb was spotless inside confirming the dealer claim of a carb. rebuild kit having been installed. The accelerator pump was obviously brand new. I reinstalled the carb with a new gasket - all with no effect.
I am currently suspecting a vacuum leak. All of the vacuum hoses appear good and most appear to be new. Everything is connected as it should be except the vacuum advance electrical switch is bypassed so vacuum hose is direct from vacuum advance to carb. The intake manifold bolts are tight and I have looked at the front and rear where the intake manifold mates to the engine and see no evidence of any mising gasket material. Note: The dealer had removed the intake manifold prior to sale - he gave me the pictures he took during his resoration work.
Looking for ideas of where to go next. Has anyone experienced something like this?
Could it be the EGR valve stuck open/rusted open or perhaps a missing EGR valve gasket? I believe the EGR value is original as there was nothing on the pre-sale repair invoice to say it was replaced.
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