Need advice on hot starting W460 280GE after shutting down for a few minutes.
My 1982 280GE starts fast when cold. But after driving for a while, if I shut down, it almost starts for a second, and then I have to crank for 20 seconds or so, sometimes pumping accelerator to get it to start. Thankfully it has a new battery, so eventually it starts.
For example, I will drive to the ferry... say 15 minutes. Then shut down for the 45 minute ferry ride. Then everyone on the boat - or at least those cars stuck behind me - hold their collective breath as it cranks and cranks until it fires up with a great noise. Alternatively I can spray some ether into the air intake, but this is a mission as well. One day, I fear it will not start, and I can't believe it is great on the starter to give it such exercise.
Clearly it is a fuel problem, but before I crack into it, I am hoping for someone to point me in the right direction. The petrol G has 400,000 miles on it, I've owned it 25 of its 40 years and the fuel pump buzzes when I turn the key, so I know it is pushing fuel in.
I don't know much about Bosch fuel injection, but am good with a wrench.
Ideas on what's wrong, and how to fix it, greatly appreciated.
Basic checks first...
Vacuum Pipes
Earth connection around engine bay
Electical connections
Warm Up Regulator
Fuel Accumalator
Nice.
I came to suggest the Accumulator, and that was your first stop. I never would have suspected the fuel non-return valve.
I was also thinking vacuum issues in the K-Jetronic, but that's not really a warm start issue.
Thanks for the sequence and instructions.
The W460 M110 engine would fire up immediately in the morning. But drive for a few miles, shut off the engine for say 30 minutes, and on turning the key, it would catch for a second or two, then require about 20-30 seconds of cranking to start. Replacing the fuel accumulator did not do anything. Replacing the WUR with the unwired tools UTCIS-V UnwiredTools UTCIS-V™ (a digital WUR) made the engine run a whole lot better, but it still had the hot start problem.
Finally, at the same time, I replaced both the O-rings on the fuel distributor pressure relief valve located on the fuel distributor and completely replaced the fuel pump non-return valve on the end of the fuel pump. Problem solved. It appears at one end or the other, fuel pressure was lost due to a bad seal. Some posts suggest this causes the warmed liquid fuel to expand into a gas thus creating a vapour lock.
When a vehicle is 40-years old if you don't want to break down at night in the rain, 40 miles from home on the first day of a long holiday weekend, it is prudent to just replace everything that tends to get old and brittle but is still reasonably affordable. Do it all at once starting at the back...