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New fuel distibutor new fuel pump but fuel pressure is 120…

Customer Question
New fuel distibutor...

New fuel distibutor new fuel pump but fuel pressure is 120 psi at the distributor--fpr new no fuel to the injectors

Mechanic's Assistant: How many miles are on the vehicle? And when was it last serviced?

120000 klm serviced every 10000 klm

Mechanic's Assistant: What is the model/year of your Mercedes?

1986 300se

Mechanic's Assistant: Are you fixing your 300SE yourself? What have you tried so far?

New fuel pump new accumulator new fpr & fuel distributor- i am a qualified mechanic

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

If i feed the system with areostart starts runs perfect for few seconds

Submitted: 7 months ago.Category: Mercedes
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Answered in 4 hours by:
12/17/2017
Mercedes Mechanic: Marty, Mercedes Technician replied 7 months ago
Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 55,216
Experience: Bosch Certified Master Tech. Over 35 years experience.
Verified

Hi, my name is***** exactly on the FD are you taking your fuel pressure measurement?

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Customer reply replied 7 months ago
the fuel line from the pump at the fuel distributer isolated from the dissy
Customer reply replied 7 months ago

e mail would be prefered ************

Mercedes Mechanic: Marty, Mercedes Technician replied 7 months ago

You need to measure the fuel pressure at the upper and lower chambers of the fuel distributor. Click on the attachment below. Let me know what you find.

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Customer reply replied 7 months ago
i am out in the bush the phone is not an option email only
Mercedes Mechanic: Marty, Mercedes Technician replied 7 months ago

That's fine. The phone call offer is an automated offer pushed by the website. It did not come from me. Let me know what you find with your pressure test.

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Customer reply replied 6 months ago
can the system operate with 140psi reading directly from the new pump--- i asume this veicle only a single pump system -- thats what it is now-- the veicle was on 100% gas for 5 yrs-- the new pump is genuine merc---the whole injector system --pump accumulator fpr-- distributor --pump relay ---injectors all new-- motor turns over --i bleed the distributor by pumping the plate motor will fire run perfectly for 2--3 seconds --thats it--nogo---drained the rotton fuel--all fresh clean fuel
what would they have done when they converted to gas--would they have had to add or change something
can only comunicate by email due to where i live
Mercedes Mechanic: Marty, Mercedes Technician replied 6 months ago

Is your pressure gauge T'd into the fuel line? If it is then the pressure is too high. Check the return line and see if you have flow on the return side. The return could be blocked going back to the tank. Remove the return hose at the engine and route it into a container then see if it will fire. I can give you some additional tests depending on what you get with this test.

Let me know what you find out.

Marty

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Customer reply replied 6 months ago
what happens fuel pressure too high --new merc pump
Mercedes Mechanic: Marty, Mercedes Technician replied 6 months ago

It would indicate a restriction on the return side.

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Customer reply replied 6 months ago
it looks like right down to too much fuel pressure--130 psi-- it is brand new merc pump from germany would this stop fuel getting to the injectors-- this psi is hooked onto the fuel line from the tank to dissy did this model originally have 2 pumps would that creat this type of problem the book says 1 pump-- the bot***** *****ne --the whole system is new--why 130--140 psi
Mercedes Mechanic: Marty, Mercedes Technician replied 6 months ago

Some had one pump and some had two. If you post the vin number I can tell you what your car is supposed to have. You never said how you were testing the fuel pressure. Are you teed into the line? Did you ever perform the fuel return test? The only time I have ever run into excessive fuel pressure is if the return back to the tank was blocked. Can you send me a picture of your fuel pressure gauge setup?

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Customer reply replied 6 months ago
vin no--wdb 126024a24267532 --one pump or 2 ?
Customer reply replied 6 months ago
return back to tank all clear--
Mercedes Mechanic: Marty, Mercedes Technician replied 6 months ago

I show only 1 pump. Send me a picture of your fuel pressure test setup.

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