10-26-2020, 08:14 PM
Hello Everyone,
I own a 1973 Mercedes 280SE 4.5 (Original Owner). The car is in excellent physical condition overall, (always has been parked indoors) but has developed a mechanical problem that I can't solve. The engine will start and idle normally for about 10-15 minutes, after which it will inexplicably die. Attempts to restart are met with gasoline leaking from the exhaust seals between the manifolds and the exhaust pipe, and also through the tailpipes along with a cloud of while smoke. If you try to restart, the engine runs very roughly, and dies again. If you press the accelerator to the floor while engaging the starter, it will start, but does not run on all cylinders. The engine dies the moment you let the accelerator up.
To date, I have replaced the spark plugs and cables, cap and rotor. I installed a Pertronix ignition, which did not help, so returned the car to stock ignition including a known good transistor box, new ballasts, coil and points--German made condenser. Additionally, all new air and coolant temp sensors where installed. The MAP holds vacuum and meets the correct resistances. The Thermal Time Switch checks out, and the cold start valve is functioning. Fuel Pressure is 30 PSI, fuel pump functions. New Fuel Pressure regulator as well. Air filter is also brand new. I removed and steel brushed all the ground straps, and all injectors are also brand new (Standard Motor Product's BOSCH equivalents). Timing is at USA factory Spec. Gasoline used is non-ethanol for the last three years, 90 octane unleaded.
The only thing I have not yet replaced is the CPU. From the experience of the other members, would the CPU cause an issue like this? Any suggestions are certainly welcome at this point as I think I may have exhausted my patience.
I own a 1973 Mercedes 280SE 4.5 (Original Owner). The car is in excellent physical condition overall, (always has been parked indoors) but has developed a mechanical problem that I can't solve. The engine will start and idle normally for about 10-15 minutes, after which it will inexplicably die. Attempts to restart are met with gasoline leaking from the exhaust seals between the manifolds and the exhaust pipe, and also through the tailpipes along with a cloud of while smoke. If you try to restart, the engine runs very roughly, and dies again. If you press the accelerator to the floor while engaging the starter, it will start, but does not run on all cylinders. The engine dies the moment you let the accelerator up.
To date, I have replaced the spark plugs and cables, cap and rotor. I installed a Pertronix ignition, which did not help, so returned the car to stock ignition including a known good transistor box, new ballasts, coil and points--German made condenser. Additionally, all new air and coolant temp sensors where installed. The MAP holds vacuum and meets the correct resistances. The Thermal Time Switch checks out, and the cold start valve is functioning. Fuel Pressure is 30 PSI, fuel pump functions. New Fuel Pressure regulator as well. Air filter is also brand new. I removed and steel brushed all the ground straps, and all injectors are also brand new (Standard Motor Product's BOSCH equivalents). Timing is at USA factory Spec. Gasoline used is non-ethanol for the last three years, 90 octane unleaded.
The only thing I have not yet replaced is the CPU. From the experience of the other members, would the CPU cause an issue like this? Any suggestions are certainly welcome at this point as I think I may have exhausted my patience.
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