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UNIMOG
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1,036 Posts
Discussion Starter #1
Hey Guys,

My friend picked up a 16v last week and we are having some problems with it. On the way back home, about 3 1/2 hours into the trip back home he down shifted from 5th to 4th @ 70mph to get into the fast lane and the car simply wouldn't accelerate. We pulled over and tried to figure anything out. The only irregularities at the time would have been that the water temp was fairly hot @ maybe 110*c.

I decided to drive the rest of the way back. It was extremely hard to get up to highway speeds. You could only use the slightest amount of throttle input, if you put in too much throttle the car would stop accelerating and would struggle to maintain speed. Also, high RPM's made it worse. After a painful minute or so, we got to 60, but thats the fastest it would go.

Made it home and parked it for the night. Next morning it was difficult to start. You had to give it a little gas and it wouldn't hold an idle. You had to hold your foot slightly on the gas to keep it running. Otherwise it would just die.

Any suggestions? Comments? I'm becoming sick of these 16v's to be honest, mine has never run right and nobody can figure it out.
 

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Premium Member
UNIMOG
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1,036 Posts
Discussion Starter #3
Fuel Pressure Regulator? or Fuel Filter?
 

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Registered
1990 Mercedes Benz 190E 2.5-16
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58 Posts
Hi JM,

What is the history of the car please?
Age? Mileage? Maintenance?

It seems you are not getting enough fuel pressure. It could be a number of things.
Please check your fuel pump/s.

Further if its difficult to start the system is not holding pressure - Fuel Accumulator.

Also check for vacuum leaks. Especially check the clear tube that goes from the fuel pressure regulator to the hose that goes into the idle air control valve and the air flow sensor.

Let us know how you get on...
 

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Premium Member
UNIMOG
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1,036 Posts
Discussion Starter #5
Hi JM,

What is the history of the car please?
Age? Mileage? Maintenance?

It seems you are not getting enough fuel pressure. It could be a number of things.
Please check your fuel pump/s.

Further if its difficult to start the system is not holding pressure - Fuel Accumulator.

Also check for vacuum leaks. Especially check the clear tube that goes from the fuel pressure regulator to the hose that goes into the idle air control valve and the air flow sensor.

Let us know how you get on...
Its an '86 with 171K Miles. Maintenance is mostly unknown unfortunately.

Fuel Accumulator - Is this the same or different as the fuel pressure regulator?

I'll check a few things out and let you know. Thanks!
 

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Registered
1990 Mercedes Benz 190E 2.5-16
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58 Posts
The Fuel accumulator ensures the fuel supply system is kept under pressure after the engine has been switched off. This improves the start phase in the KE-Jetronic system.

The fuel pressure regulator maintains a constant fuel pressure for fuel for normal driving conditions and at wide open throttle. But really the fuel pressure regulators do not often go bad.
 

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Premium Member
UNIMOG
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1,036 Posts
Discussion Starter #7
How would I test the fuel accumulator? I really appreciate the help btw.
 

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Registered
1990 Mercedes Benz 190E 2.5-16
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58 Posts
No problem, its a bit difficult to test a fuel accumulator.
You really need to do a fuel pressure test - hot and cold start.

Ideally you need to take it to a KE specialist.

But...First check all vacuum hoses, condition of rubber hoses, all connections, especially those going to the sensors at the front of the engine and those at the back of the air filter box.

Also, although not related check the fuses on top of the OVP relay.

Lastly can you smell any fuel inside the cabin or when you open the hood...?
 
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