450 SEL poor running hot only - Mercedes-Benz Forum

 
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post #1 of 6 (permalink) Old 12-09-2011, 09:58 PM Thread Starter
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Vehicle: 1973 450 SEL
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450 SEL poor running hot only

I recently acquired a 1973 450 SEL that had been sitting by the road for 9 years with a bad fuel pump and leaky non fuel injection hoses. These were fixed and now it starts. It runs well and revs properly when cold, but quits running well once it warms up with driving. It won't rev about 2K and has no power. Any application of throttle will cause it to bog. In some ways it feels like it is not getting fuel. It has electronic fuel injection.

Any ideas as to the cause of this problem
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post #2 of 6 (permalink) Old 12-10-2011, 03:10 AM
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Fuel filter is my first guess. Change that out. Did you dump all the old gas prior to putting it on the road?
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post #3 of 6 (permalink) Old 12-10-2011, 09:15 AM Thread Starter
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The fuel filter is new along with the fuel pump and all hoses. The system was dry when I got it including the fuel tank. Since the problem only happens after it warms up, I am thinking that it must be a sensor problem.
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post #4 of 6 (permalink) Old 12-15-2011, 06:42 PM Thread Starter
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I have found the answer to the problem. The hose to the pressure sensor was dried out and it was leaking vacuum. A new hose fixed the problem completely. Before, as long as the start injector was delivering fuel it ran ok, but once this switched off, the regular injectors were not being told to supply more fuel when needed.
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post #5 of 6 (permalink) Old 08-31-2015, 11:12 PM
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Where is the pressure sensor hose located? Thanks!


Quote:
Originally Posted by ranchodeieve View Post
I have where is the "pressure sensor hose" located? Thanks! found the answer to the problem. The hose to the pressure sensor was dried out and it was leaking vacuum. A new hose fixed the problem completely. Before, as long as the start injector was delivering fuel it ran ok, but once this switched off, the regular injectors were not being told to supply more fuel when needed.
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post #6 of 6 (permalink) Old 09-06-2015, 02:22 PM
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Hi,
look for this easy-to-find part...http://www.bosch-automotive-traditio...er_gb_w734.jpg

regards
Norbert
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