Help with 89’ 300se fuel pressure regulator vacuum line issue
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1989 Mercedes 300SE
Help with 89’ 300se fuel pressure regulator vacuum line issue
I have a very low mile 300se that had been having hot start problems since purchase.
After changing fuel filter and accumulator, car runs better, but still has a hot start problem.
I recently noticed the system is dumping fuel into my engine oil since the oil has a very strong fuel smell. I also noticed fuel inside the fuel pressure regulator vacuum line that connects to the breather at the airbox. Does this mean I have a failed fuel pressure regulator that is dumping fuel into the engine? Is it normal to have fuel in that line?
Would appreciate any insight. Thanks in advance!
After changing fuel filter and accumulator, car runs better, but still has a hot start problem.
I recently noticed the system is dumping fuel into my engine oil since the oil has a very strong fuel smell. I also noticed fuel inside the fuel pressure regulator vacuum line that connects to the breather at the airbox. Does this mean I have a failed fuel pressure regulator that is dumping fuel into the engine? Is it normal to have fuel in that line?
Would appreciate any insight. Thanks in advance!
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Joined: Feb 2012
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From: Phoenix
222 S-65
OP there should be zero fuel in any vacuum lines. Follow the fuel to the leak. Any leaks will make an extended crank time issue.
The car is old enough to have injectors that leak down or ‘pee’ for a fuel spray pattern. False air leaks (any air that isn’t measured by the airflow sensor flap) will cause havoc.
The car is old enough to have injectors that leak down or ‘pee’ for a fuel spray pattern. False air leaks (any air that isn’t measured by the airflow sensor flap) will cause havoc.
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Joined: Dec 2006
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From: London
300sel- w109 .1971
OP there should be zero fuel in any vacuum lines. Follow the fuel to the leak. Any leaks will make an extended crank time issue.
The car is old enough to have injectors that leak down or ‘pee’ for a fuel spray pattern. False air leaks (any air that isn’t measured by the airflow sensor flap) will cause havoc.
The car is old enough to have injectors that leak down or ‘pee’ for a fuel spray pattern. False air leaks (any air that isn’t measured by the airflow sensor flap) will cause havoc.
There should be no leakage or fuel smell
I would remove the plugs to ascertain injector leakge as fuel smell will be apparent after a short wait
fuel regulater leakage: first check the vaccum pipe here, followed by cold start injector.
Fuel accumulator diaphragm for leakage and lastly replace the cis injectors if old , not serviceable item.
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,607
Likes: 1,208
From: Phoenix
222 S-65
Injectors are serviceable. If you have the tools to do it. I’ve had many start out leaking and peeing for a ‘spray pattern’ that clean up to as new and hold pressure. Some end up in the trash.
Are all the correct injector seals still available? It has been over a decade since I have fiddled with one.
Are all the correct injector seals still available? It has been over a decade since I have fiddled with one.
Last edited by JohnLane; Sep 2, 2024 at 10:15 AM.
