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mbfixer, Mercedes Technician
Category: Mercedes
Satisfied Customers: 453
Experience:  20 plus years hands on experience old cars new cars SDS-WIZ on hand to help assist you.
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My Car Starts But Then Dies After Sometime

Customer Question

My car starts but it dies a few seconds after starting.

Submitted: 7 years ago.
Category: Mercedes
Expert:  mbfixer replied 7 years ago.

What repairs have you made? Has the car been used lately or sitting? We need to find out what has failed. The engine needs fuel-spark and air to run. We need to find out which one of these items are not working properly and not letting the engine to start. A simple test would be to spray some starting fluid into air cleaner and see if the engine will run, and by spraying some amounts in quick bursts, you may be able to keep engine running. Where do you want to start? If car has been sitting for long periods of time, we will want to inspect if the fuel distributor plunger is seized. Let me know what you have done and I will be glad to continue.

Customer: replied 7 years ago.

The car has been sitting for a few months now. However, this issue was happening before I parked it, that's why its been sitting cause I cant get it cranked. The only thing I did before it died was replace an overload relay that was addressed in my last online session with JustAnswer. After I made the repair, it drove great for about a month, was running very strong. I turned it off, and fifteen minutes later it wouldn't start with the symptoms I'am describing.

Expert:  mbfixer replied 7 years ago.

Your first post mentions engine starts and dies, this last post says engine will not crank. So I am thinking the engine will not turn over-crank. This system gets a 12 volt signal that comes from the ignition switch through neutral safety switch to the starter motor. For sure we need a strong battery. The next item to try is put shifter into neutral and try to start the engine. This car has a neutral safety switch mounted on the side of transmission. We will need a 12 volt test and/or a volt meter for our next test. Also have a jumper wire close by so we can by pass NS switch if the switch tests bad. Then first test is to get a 12 volt test light and test for power at the small violet wire on the starter motor when the ignition key is turned to the start position. You will need good strong battery and a helper to turn key while you ground your test light at the negative terminal at the battery and the other end of the test light to the small violet wire on the starter motor. With key turned to start position you should have power (lighted) test light. Let me know what you have.

Also get that starting fluid, due to sitting I would suspect multiple problems and together we can try to solve them all.

Customer: replied 7 years ago.

It does crank then dies in 1 to 2 seconds. It will crank even 10 to 20 times if i try, but always goes dead after a few seconds. What do you think now?

Expert:  mbfixer replied 7 years ago.

I am thinking that the car is out of fuel or the electric fuel pump is not functioning properly. Let us test to check if the fuel pump is running when the engine is being cranked- turned over- started. You will need a helper for this test. Have your helper turn the ignition key -start the engine you lay down under right rear section of the car. The electric fuel pump is located above the right rear axle shaft, behind a black plastic shield. Remove shield and put your hand right on the fuel pump itself. While trying to start engine fuel pump must run. Also you could spray some starting fluid and see if the engine will start. We are testing to find out if our problem is fuel related or spark related. A common problem is the fuel pump relay that is what I am thinking, no fuel.

Customer: replied 7 years ago.

I do have fuel in the gas tank. Also, will I hear the fuel pump running, and if I hear it running, does that mean its functioning properly? As for using the starting fluid, this car does not have a carburetor, so where do I spray the starting fluid? Also, what is the location of the fuel pump relay?


Expert:  mbfixer replied 7 years ago.

If the fuel pump is running then the fuel pump relay is good. So let us make sure that the fuel pump is running. As for where to spray starting fluid, remove the plastic elephant tube for the air filter assembly and spray right into opening at air filter assembly. Keep your face away. The engine may fart or burp through the intake, so be careful. The fuel pump relay is located over by battery, has the word KICKDOWN written on the top of relay. By pass pins 87 and 30, this will make fuel pump run all the time even with key off, so remove the jumper wire when finished with your test.