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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #1
So i started asking about this problem in another thread, but i decided to re-post it with a more relevant title. Basically the problem i was having was a no start due to lack of fuel. I turned the key, went out and pulled the brand new fuel pump relay, and plugged it back in. The fuel pumps didnt turn on, however i could feel the relay click shut. So instead of trying to diagnose it, i ran a hotwire and ground straight from the battery through a toggle switch and too the pumps. They were however both seized up, but after some playing around i managed to free them up. I now have gas to the fuel distributor and to the injectors, but after pulling an injector and turning the pumps on i realized, that fuel isnt passing through the injectors. My question is what should the fuel pressure be going into the distributor? And right before the injectors? I plan on testing that tomorrow. I wanna know if you think the pressure is too low for the fuel to pass thriugh the injectors, or if maybe theyre clogged? They seem to be purely mechanical, so my question is shouldnt they always be open? Any help would go a long way. If i pull the injector off and turn on the pump the fuel comes out at a steady pace but not very pressurized, if i hold my thumb over tge line the pressure builds up quite a bit. Any way to test injectors?
 

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86 300e Anke
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1,252 Posts
Are you using that wire to KEEP them running while turning over?

Also... if theyve 'run dry' you are likely to have air in the lines that need to be cleared out by starting attempts... it may not fire right up just because the pump(s) is(are) running...

VERY MUCH a victim of this! :D


*** IF you are sitting still (NOT RUNNING) you are likely NOT to see fuel at the injector... the distributor (?) hasnt sent it there yet...
(... the more system-savy folks will have to approve this statement. )

Between locked-up fuel pumps and the injectors is a fuel filter that was changed... WHEN? :eek:
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,744 Posts
The air plate must also be depressed to release fuel from the FD.

Sent from my DROID2 using AutoGuide.Com Free App
 

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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #4
Ive tried keeping them running while turning it over and turning it on for about 5 seconds before turning it over, nada. The fuel filter and accumulator appear to be new, however i still blew some trash out when i had them apart. I definitely have fuel at the top end, i ran the pumps with different components off to bleed out the system. As for the air plate, how would you go about making sure thats down? Also, my airflow meter appears to have a crack, any ideas on what this controls and how neccesary? Come on guys i really need some help here. How aboutnpsi at the distributor? Or injectors?
 

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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #7
Okay, will check to see how much fuel im getting in 15 seconds. I have a question about the fuel distributor, does it amplify the fuel pressure before sending it to the injectors? I went and pulled off all my injectors, they're all in extremely bad condition, so im wandering if all the rust on them is preventing them to stay shut. Even if i had relatively low fuel pressure wouldnt the car at least try to run if the injectors are working properly? Regardless' im considering replacing all six, i mean theyre conpletely covered in rust -_-'
 

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1987 300E, 1955 Plymouth Belvedere, 2005 Silverado 4x4
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963 Posts
The Fuel Distributor does not amplify the fuel pressure. It is simply an elaborate slide valve that controls fuel flow to the injectors which are actuated entirely by fuel pressure. The CIS-E system needs around 80psi to operate.
 

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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #9
So the pumps shouldbe putting out 80psi? Just bought two new pumps and all new injectors, they come in next week. In 15 seconds I pump less than 1/4 liter into the front end :|
 

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1987 300E, 1955 Plymouth Belvedere, 2005 Silverado 4x4
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963 Posts
Zack, It sounds like your car is going to be down for a few days waiting on parts, you might want to check your gas tank pickup tube to make sure the filter screen is not clogged with rust flakes and sediment. Even weak fuel pumps should be able to move a decent volume of fuel when the system is not sealed and building pressure, but a clogged pickup tube and/or fuel filter will restrict the amount of fuel the pumps can draw from the tank.
 

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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #11
The pickup tube is the one before the fuel filter, correct? Or if not where would this screen be so i can clean it? I would hate to destroy two new pumps :|
 

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1987 Mercedes-Benz 260E (SOLD) ;;; 1995 Mercedes-Benz E320
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72 Posts
Discussion Starter #12
Where is the pickup tube? I'm assuming its the main feed line to the fuel pumps, but how can I access and or remove it to check for debris?
 

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1987 300E, 1955 Plymouth Belvedere, 2005 Silverado 4x4
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963 Posts
Pickup tube is in the fuel tank where the fuel line exits the tank. it screws into the tank and can be removed for inspection or cleaning. just make sure your tank is empty when you remove it.
 

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Engine Stop Sunddenly

My Merc 260E 1987 is the engine always stop sunddenly while drive. But it can easy restart and can persue the travel. It must be dangerous drive in the town or overtake the lorry. Before it happen, the engine likely lost the power and then it stop. Some machenic said it because the fuel not turn down. Many part i have change like fuel pump, fuel filter and overhaul the engine but the problem still occur. Please friends, help me for idea. Thanks
 
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