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  #1  
Old 05-23-2002, 11:17 PM
sixto's Avatar
smoke gets in your eyes
 
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Location: SF Bay Area
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603 won't start

I had the injectors out of the engine. I put them back and buttoned everything up and now it won't start. I cranked it in 10 second bursts about 20 times and not a sign of catching. There's no fuel at the delivery valves or the injectors. There's a little fuel when I crack the line from the pump to the big filter. There's no fuel when I crack the line from the big filter to the IP. The big filter is pretty full but not overflowing. There's an air bubble in the small filter. I don't know if it was there when the car was running.

I noticed that part way though cranking, the stop lever was all the way down and tended to go down on its own. I tied it in the up position and cranked a few times and now it stays up (sounds like a men's product endorsement). Does this mean anything?

Any help is appreciated.

Thanks,
Sixto
91 300SE
87 300SDL ... start, d@mn it
81 300SD

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  #2  
Old 05-24-2002, 12:54 AM
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sixto,

Older model cars had a hand operated pump to purge the air from the system, but I think you have to run the starter until it starts on your car. You are trying to push air out of the system, which is compressible, and the pump stroke is a miniscule volume at each injection stroke (at 30 mph, all the injectors squirt a combined total of 1 gallon or so in an hour if you get 30 mpg). The result is that the poor starter is cranking away at the whole motor, pumping all kinds of air through the combustion chambers, when all you want it to do is pump a few cubic centimeters of air out of the injection system. The injection pump is a kind of positive dispacement pump, and when they get air in them or the discharge lines, they have a great deal of difficulty generating any real pressure.

What happens is the bulk of the air has to be pushed back to the fuel tank and what is left has to be displaced/absorbed by fuel under high pressure. The injectors are like little relief valves and there has to be enough pressure under them to lift the valve stem off the nozzle seat. With a significant amount of air in the system, you don't get that much pressure as the small injection pump stroke is designed to develop that pressure each stroke with an incompressible liquid, not a very compressible gas. So, it can pump the air back to the tank, but that is a long way, and it takes a lot of strokes which means the engine has to turn over a lot of times. Stopping and starting is a little like taking three steps forward and slipping two steps back as once the pump stops pumping the air will tend to go back to the top of every one of the little loops in the injector tubes and anywhere else. It also relieves the pressure in the injection lines to the injectors and any headway you made getting the air to dissolve in the fuel is undone, a lot like taking the top off a bottle of coke and having the gas come out of solution.

So, you have just crank it for quite a while. It is a strain on the battery and the starter. Someone here suggested doing these things with the engine warm to help the process along. Good luck, 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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  #3  
Old 05-24-2002, 01:45 AM
lrg lrg is offline
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I'd second JimSmith's analysis. You can really crank for quite a while without doing damage. I recently blew my 80 amp glow plug fuse and had to start the car cold. I cranked non stop for 2 60 second periods with only a 1 min cooldown (for the starter) in between. The battery easily handled it and I've had no problems with the starter. (by the way the car started in 45 degree weather) So before you do anything else, crank away to see if you can get all the air out. It should eventually catch. Good luck.
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1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
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  #4  
Old 05-24-2002, 03:56 AM
Gerard's Avatar
91 300CE M103: 80 450SEL
 
Join Date: Nov 2001
Location: Dublin, Ireland
Posts: 112
Yep!!

In the owners manual for my 603 it states, to bleed the fuel system you have to crank for a minute. Dont be afraid!!

Gerard
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  #5  
Old 05-24-2002, 05:21 AM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: SF Bay Area
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Quote:
Originally posted by JimSmith
Someone here suggested doing these things with the engine warm to help the process along.
With the engine warm? How about with the engine running?

Seriously, thank for the advise. I'm going to have to dig up a battery because this puppy's not going to crank for a minute straight after sitting for the last couple of months.

I don't suppose a 617 fuel pump with hand primer will fit a 603 IP.

Sixto
91 300SE
87 300SDL
81 300SD
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  #6  
Old 05-24-2002, 08:04 AM
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Location: Old Lyme, Connecticut
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sixto,

I realized after I posted that how it sounded. But the original suggestion was with regard to a fuel filter change, and the suggestion was to get the car up to temp, then change the filter, without letting the engine cool down first. The idea was cranking a warm engine is a little easier and the car is more likely to start warm without the best conditions. Sorry. 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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  #7  
Old 05-24-2002, 09:07 AM
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Join Date: Aug 2001
Location: Milford, DE
Posts: 1,470
Sixto

You may also want to try to loosen the 14mm fittings on the injectors while an assistant cranks the engine. Loosen and tighten the fittings while the enigne is cranking. This will allow the system to bleed more quickly. I have used this technique on several 616 and 617 engines and it really reduced the amount of crank time before the engine would start.

The 602/603 engines seem to be more prone to this problem than the older 616/617 versions.
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  #8  
Old 05-24-2002, 12:41 PM
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Location: eastern ND
Posts: 657
Sounds like air in the injector pump. My old daBenz with a vacuum governor has a bleed screw at the top of the pump. Located on top, beside #4 injector line. Had to bleed there when I did the injectors in mid 80's. Worth checking for on your pump.
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  #9  
Old 05-24-2002, 01:59 PM
LarryBible
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TimFreeh is, I think, on to the solution.

Once you get the main filter full and it is flowing fuel to the IP, crack open all the lines AT the injectors. Have someone crank until you see fuel dribbling from one or more of them. Once you see fuel somewhere, mentally note which injector(s) and tell the assistant to stop crankiing. Tighten the injector line(s) from which you saw the fuel and tell the assistant to begin cranking again. Once you see fuel again, repeat until you see fuel at all injectors and have tightened all the lines.

Then start it.

Best of luck,

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