Why does my Mercedes 450SL not start the fuel pump?
2. when you turn the key to start the engine the key stays there and the car keeps cranking if you let go of the key. its like the spring in the ignition tumbler spring broke which after starting the car puts the key back into the aux 2 position. could either of these known issues be affecting the fuel pump circuit or show signs of a short?
What is the fuse on a Mercedes 450SL?
It is most likely fuse 14, 8 amp. To be sure, you should get accustomed to using the on-line chassis and engine manual (link to MBUSA Startek manuals is in stickies). The electrical diagram for your car is there (see below).
What do I need to troubleshoot my Mercedes Benz?
Troubleshooting fuel related problems is not very difficult and you can check the fuel pressure yourself. Checking the fuel pressure is very simple. For this test, you will need a fuel pressure gauge. What you need is a fuel pressure gauge with Schrader valve adapter.
What’s the fuel pressure on a Mercedes Benz?
A great and affordable gauge that we have used in the past is this Actron Fuel Pressure Gauge which works on Mercedes-Benz cars. Turn the engine off and connect this gauge to the Schrader valve test port shown in the picture below. Start the car and you should be able to get around 60 psi.
2. when you turn the key to start the engine the key stays there and the car keeps cranking if you let go of the key. its like the spring in the ignition tumbler spring broke which after starting the car puts the key back into the aux 2 position. could either of these known issues be affecting the fuel pump circuit or show signs of a short?
It is most likely fuse 14, 8 amp. To be sure, you should get accustomed to using the on-line chassis and engine manual (link to MBUSA Startek manuals is in stickies). The electrical diagram for your car is there (see below).
Do you need a relay for a fuel pump?
There is no real need for the relay at all – it is just a safety to stop pumping fuel in a crash or whatever so until you sort the car out you can leave it jumpered. Pump will run and circulate gas whenever key is on. You never said if you checked the fuses.
Where is the fuel pressure regulator on a Mercedes 450SL?
The Fuel Pressure Regulator, on top of the fuel “rail” supplying the injectors, maintains the injector supply at a nominal 30 PSI (adjustable by turning the nut on top).
Where is the fuel pump on a Mercedes Benz?
The fuel pump is located under the car on the right side below the fuel-filling inlet near the fuel tank. Consult the article on safely jacking up your vehicle and placing your M-B on jack stands. Be sure to always wear safety glasses anytime you’re working under your car.
Why does my 1974 450SL fuel pump not start?
BTW, the main relay also clicks when you first turn the key. The new relay won’t work. It is the wrong fuel pump relay for the 1974. What was the part number on the relay you removed?
The fuel pump is located under the car on the right side below the fuel-filling inlet near the fuel tank. Consult the article on safely jacking up your vehicle and placing your M-B on jack stands. Be sure to always wear safety glasses anytime you’re working under your car.
Where is fuse 14 on a fuel pump?
I have paper copy of 74 diagram and it shows fuse 14 as fuel pump fuse. For the tach, it is possible that the signal wire is disconnected. Not sure exactly how 74 is connected, but if you follow the small wire (usually green) from the distributor, it should lead down to below coil.
What’s the problem with my 1974 450SL?
It ribs up fine when cold, no issues. It seems the AAV and the cold start valves are working good, and it idles down after it closes, then after the temp bulb reaches operating temp, the computer changes to normal operation, and relies on throttle position, MAP, and the temp sensor, is the MAP the same P/N as the one you took off?????????????????
What to do if your 450SL is not running?
Bought 450sl (10704412015***) not running, (set for 12 yrs) gas tank stopped up removed and cleaned, along with fuel pump/lines. Replaced points with Petronic 1885, along with replacing coil and wired per thread on this forum. Engine cranks fine cold and runs until it reaches operating temperature and idles down.
What to do if your Mercedes 450SL dies?
Replaced points with Petronic 1885, along with replacing coil and wired per thread on this forum. Engine cranks fine cold and runs until it reaches operating temperature and idles down. Length of idling before engine dies varies each time.
It ribs up fine when cold, no issues. It seems the AAV and the cold start valves are working good, and it idles down after it closes, then after the temp bulb reaches operating temp, the computer changes to normal operation, and relies on throttle position, MAP, and the temp sensor, is the MAP the same P/N as the one you took off?????????????????
Bought 450sl (10704412015***) not running, (set for 12 yrs) gas tank stopped up removed and cleaned, along with fuel pump/lines. Replaced points with Petronic 1885, along with replacing coil and wired per thread on this forum. Engine cranks fine cold and runs until it reaches operating temperature and idles down.
Replaced points with Petronic 1885, along with replacing coil and wired per thread on this forum. Engine cranks fine cold and runs until it reaches operating temperature and idles down. Length of idling before engine dies varies each time.