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Discussion Starter #1
Hi all,

i am buying a 450SLC 1979 that has been stood for 2 years or so

the buyer has done the following to it

new fuel pump
new fuel filter
new spark plugs
fresh petrol
fuel tank was reconditioned

the car starts for approx 30seconds to 1 minute and then the engine dies/cuts out

any idea why this could be and how can i fix it ?

many thanks

Hass
2633950
 

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1983 380 SL
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Have you checked anything? We could use a bit more information... like is it spark related or fuel related?
Running for a minute and then cuts out could be heat related. How long does it need to sit after it cuts out before it will restart?
Wild guess... Ignition control module.
 

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Discussion Starter #3
Have you checked anything? We could use a bit more information... like is it spark related or fuel related?
Running for a minute and then cuts out could be heat related. How long does it need to sit after it cuts out before it will restart?
Wild guess... Ignition control module.
hi thanks for the reply i have not taken delivery yet of the car

but when i do so i will check a few things

what do you suggest i check first ?

many thanks

h
 

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It’s most likely to be fuel related. Be prepared to either educate yourself on how the CIS or K-Jet fuel system works and purchase a fuel pressure gauge to help you diagnose or find a shop in your country that knows these systems. I would think in the UK you still have several shops with the knowledge base to help. Unlike in America where few shops with exceptions to MB specific still know how to work on them.
 

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1983 380 SL
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hi thanks for the reply i have not taken delivery yet of the car

but when i do so i will check a few things

what do you suggest i check first ?

many thanks

h
I would be interested in knowing how long it runs before it cuts out. Cutting out a second or two after start has one set of things to be checked but cutting out after a minute may indicate a different set of things to check.

I believe the 1979 450slc came with K-Jet fuel injection a.k.a. CIS (continuous injection system). Inasmuch as the injectors are always spraying (they don't turn off and on), with the amount being sprayed under the control of a combination of the fuel distributor, fuel pump and several other control/adjustment components, a wild guess would be loss of fuel pressure.

Alpha is correct when he says the place to start is to check fuel pressure, but fuel pressure is far from the only thing that could cause the symptoms you described.

When you take delivery of the vehicle perhaps you could take a video of the engine starting and then cutting out after a minute. If you have a means to check fuel pressure we will be able to show you where to check it and what values you should get. If you don't have access to a fuel pressure gauge, Harbor Freight sells a kit that has all the adapters you would need.

Welcome to the forum.
 
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