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  #61  
Old 03-30-2008, 05:00 PM
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Originally Posted by funola View Post
I did wonder about the new black hand primer pump ($10 from ********az) whether it provided enough pressure to bleed the system. Do you know what the spec should be? The old white handled pump leaked fuel with every stroke, pretty ridiculous even when fuel was cheap. Does yours do that? I was afraid of running out of fuel if I continued to pumping on it that's why I replaced it with the black pump before doing anything else.

.

The fact that the old primer pump leaks fuel should give you some indication that the fuel system is not tight and that you surely can aspirate air on the upstroke.

So, the problem with getting fuel to the IP is compounded by an inadequate primer pump.

I'd say that the new pump would certainly provide the necessary fuel flow to the IP and will fill the system until there is relief at the check valve............without the problem of introducing additional air during the process.
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  #62  
Old 03-30-2008, 05:48 PM
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I agree with the logic Brian, but oddly I have never had the problem with the leaking pump sucking air in in the upstroke. But mine have never been gushers, just enough to get your hands covered in Diesel and leave a stain on the ground. Jim
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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
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  #63  
Old 03-30-2008, 09:12 PM
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Quote:
Originally Posted by Dionysius View Post
Any takers to help me print a procedure to hang in my garage when I have forgotten all of the above:
Did you read my suggestion in post #55 ?
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  #64  
Old 03-30-2008, 10:42 PM
Dionysius
 
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Originally Posted by leathermang View Post
Dionysius,
I suggest you start a new thread to ask this... you should get more hits that way ...so better info.... try to make the title catchy.... there IS an ART to this forum stuff.....LOL
Thank you for tip. I will do this shortly.
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  #65  
Old 03-30-2008, 11:16 PM
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"the "union screw" at the fuel fliter, which is the horizontal outlet line seen in the photo in post #16, should be cracked and the primer should be operated untl clear fuel emerges from the union screw.

Then, the screw is tightened and the primer pump is then operated until an audible rattling sound is heard at the IP bypass valve."

I did follow the procedure above pumping approx 150 times (with the updated black priming pump) without success. After clear fuel emerges from the union screw and tightened, you now have a closed system. I don't understand how further pumping will rid any more air and make the check valve chatter. Where is the air suppose to go? What finally did the trick for me was cranking with the check valve out, which got rid of trapped air and got fuel in.

Isn't it kind of ridiculous to have to pump 150 times, lose a quart or more of fuel and make a mess in the process, lose some skin, and to add insult to injury, if you don''t wash off the diesel soaked motor mount, you end up ruining it. There's got to be a better way!
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  #66  
Old 03-30-2008, 11:25 PM
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Quote:
Originally Posted by funola View Post
I did follow the procedure above pumping approx 150 times (with the updated black priming pump) without success. After clear fuel emerges from the union screw and tightened, you now have a closed system. I don't understand how further pumping will rid any more air and make the check valve chatter. Where is the air suppose to go? What finally did the trick for me was cranking with the check valve out, which got rid of trapped air and got fuel in.

Isn't it kind of ridiculous to have to pump 150 times, lose a quart or more of fuel and make a mess in the process, lose some skin, and to add insult to injury, if you don''t wash off the diesel soaked motor mount, you end up ruining it. There's got to be a better way!
You do have a closed system. However, the primer pump is designed to force fuel to the IP and pressurize the system. When the pressure gets above a setpoint.........7 psi??...........the check valve opens briefly and allows fuel/air to return to the tank via the return lines. In theory, the check valve will chatter when it does this.

But.........and this is important..........if the primer pump is not up to the task of achieving the setpoint on the check valve, you can pump forever and you won't accomplish anything.

So, your initial question remains a valid one: Does the new style primer pump achieve sufficient pressure to crack the check valve.

You might wish to give this a test. Disconnect the line from the IP to the secondary.........at the secondary.........and pump the primer. If you get fuel from this open line..........the pump is doing it's job and the check valve just does not chatter..........for unknown reasons. If you don't get fuel..........the pump is not capable of cracking the check valve.........which would be very bad news.
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  #67  
Old 03-30-2008, 11:42 PM
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I believe the original design pump is a style of pump called a positive displacement pump. The pressure attained by the pump is a result of the rate at which you operate the pump, which you should be able to notice as you increase the stroke rate - the resistance goes up. Each full stroke pushes the same quantity of fluid, thus the positive displacement label. The increased resistance comes from forcing more fluid against the system resistance in a given time.

You find with the old style pump achieving the pressure to pop the check valve takes a bit of effort, but it is not something that will give you a strain or cause you to break out in a sweat. I have no idea what the new pump is as I have never installed one. Jim
__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)
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  #68  
Old 03-30-2008, 11:44 PM
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"You might wish to give this a test. Disconnect the line from the IP to the secondary.........at the secondary.........and pump the primer. If you get fuel from this open line..........the pump is doing it's job and the check valve just does not chatter..........for unknown reasons. If you don't get fuel..........the pump is not capable of cracking the check valve.........which would be very bad news."

You mean the nylon line? I'd have to heat it up with a heat gun to soften it and probably destroy the line in the process. It would be an interesting test which I may do if I can locate a new piece of clear nylon to replace it with. You didn't mention it but I assume once that line is disconnected at the secondary, the open port on the secondary has to be plugged in order for pressure to build.
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  #69  
Old 03-30-2008, 11:48 PM
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Originally Posted by funola View Post
"

You mean the nylon line? I'd have to heat it up with a heat gun to soften it and probably destroy the line in the process. It would be an interesting test which I may do if I can locate a new piece of clear nylon to replace it with. You didn't mention it but I assume once that line is disconnected at the secondary, the open port on the secondary has to be plugged in order for pressure to build.
Just disconnect the banjo at the secondary and leave it wide open. The supply side will pressurize and the check valve will open and allow fuel to spill out the open banjo fitting.
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  #70  
Old 03-30-2008, 11:48 PM
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On second thought it'd be easier to take the check valve out and plumb it up direct to the primer pump and a pressure gauge. I bought 2 of those primer pumps and have one still in the box.
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  #71  
Old 03-30-2008, 11:50 PM
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Quote:

So, your initial question remains a valid one: Does the new style primer pump achieve sufficient pressure to crack the check valve.

You might wish to give this a test. Disconnect the line from the IP to the secondary.........at the secondary.........and pump the primer. If you get fuel from this open line..........the pump is doing it's job and the check valve just does not chatter..........for unknown reasons. If you don't get fuel..........the pump is not capable of cracking the check valve.........which would be very bad news.
I just replaced the original leaking pump with a Black One (circa $14) and I tested it. The ball valve chirps like a cricket in summer. This proves that the pressure is meeting spec.

It was so easy to replace and I had been thinking it would be difficult. 30 minutes. Use a 17mm crowsfoot to tighten. I removed the old one with a Vice Grip since I did not worry about destroying it.
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  #72  
Old 03-30-2008, 11:54 PM
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Will it? Once that banjo is off, fuel will gush out the open port on the head as you pump and there won't be any supply pressure. Am I missing something?

Quote:
Originally Posted by Brian Carlton View Post
Just disconnect the banjo at the secondary and leave it wide open. The supply side will pressurize and the check valve will open and allow fuel to spill out the open banjo fitting.
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  #73  
Old 03-31-2008, 12:00 AM
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Well there you go I don't need to do the test anymore! I must have a leak in my system. I think I'm gonna plumb that 15 psi gauge in there and see if it holds pressure.

Quote:
Originally Posted by Dionysius View Post
I just replaced the original leaking pump with a Black One (circa $14) and I tested it. The ball valve chirps like a cricket in summer. This proves that the pressure is meeting spec.

It was so easy to replace and I had been thinking it would be difficult. 30 minutes. Use a 17mm crowsfoot to tighten. I removed the old one with a Vice Grip since I did not worry about destroying it.
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  #74  
Old 03-31-2008, 12:14 AM
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"Instantaneous start remedy try WD-40 or diesel starting fluid."
I tried WD-40 after popping the air cleaner cover and squirting it in as my helper cranked and it didn't do a thing! (I'm too smart and did not try the starting fluid ) I asked the fuel injection shop about that and they said WD40 works better in a DI engine and may or may not work in an IDI.
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  #75  
Old 03-31-2008, 12:44 AM
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Quote:
Originally Posted by funola View Post
Will it? Once that banjo is off, fuel will gush out the open port on the head as you pump and there won't be any supply pressure. Am I missing something?
The banjo at the secondary.........not the banjo at the check valve.........
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