1979 450 SL Fuel Problem - Mercedes-Benz Forum

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post #1 of 4 (permalink) Old 05-16-2013, 06:43 PM Thread Starter
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Vehicle: 1979 450 SL
Location: Augusta, Ga USA
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Post 1979 450 SL Fuel Problem

New to this, so be easy on me. I have a 1979 450 SL that I drive a little. I just installed a new fuel pump and fuel filter and drained fuel tank. Gas was very bad. I ran a fuel injector cleaner and added a couple gals. of gas to tank with cleaner. After a few hours I started car and it would not stay running for more than 2 mins. I then added to gas tank 6 gals of 93 oct gas. The fuel gauge did not move. So now I start the car and it runs no more than 2 mins. the dies. I think the fuel tank fuel level unit 107 542 08 04 is now bad. Question 1 is can I by pass this unit. I think the unit is telling the on car elec. system the car is out of gas and cuts off and I could be wrong. Question 2 does anyone know were to get a new level unit. Car Parts Discount does not have one and said VDO stopped making them. And they were very helpful to send me to this forum. If you think I am barking up the wrong tree please let me know so I can get the MB on road again. Could it be the new fuel filter is not working? And help thanks Ron
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post #2 of 4 (permalink) Old 05-19-2013, 06:38 AM
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There's no electrical connection between the fuel sending unit and the car. Look for the forum moderator, GermanStar - he's got every part I've ever needed. also, look to Autohaus.com, Peachparts.com and eBay for replacement ones.
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post #3 of 4 (permalink) Old 05-19-2013, 09:57 AM
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You might want to move over to the 107 forum here. R/C107 SL/SLC Class - Benzworld.org - Mercedes-Benz Discussion Forum

A lot of very helpful people on a very active forum. There is a sticky topic, at the top of the thread list called Encyclopedia Germanica v107 that is a compilation of some very informative and important threads, reading through them can help with a lot of questions.

That said, have you changed out the fuel filter yet? Also, the fuel distributor has tiny screens in the "in" and "out" ports that are known to get gunked up from sitting with aged fuel.

Just a few wild guesses, good luck.

Remember: It's not just a car. It's an Adventure.
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post #4 of 4 (permalink) Old 05-19-2013, 06:06 PM
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you may have a bad gas tank , to test fill it , if car then run fine , that is it .the car will run out of gas with a half tank .if you want to see the problem in action , remove the gas gauge sending unit [ under soft top ] ,. look inside tank , you will see a round plastic container , start car , and watch , if tank is bad , the container will go empty , engine will stop .[ dont create a spark ]
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