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Old 01-24-2011, 10:19 PM
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Join Date: Jun 2002
Posts: 60
fuel line replacement - no start

89 420 sel 205k

replaced fuel pumps, fuel filter, fuel strainer, accumulator and all supply/return fuel lines from the gas tank to the engine (did not replace the vent line)

put in some gas, primed the system and tightened a few bolts to fix two small leaks.

car won't start. is it possible that it is vapor or air locked? i thought the vent line would eliminate that from happening. any suggestions would be helpful.

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Old 01-25-2011, 01:56 AM
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Join Date: May 2001
Location: Northern Va.
Posts: 3,386
How did you prime the system? I would remove the fuel pump relay and jump pins 7 and 8 in the socket. The pumps will run full time then.

This may be caused by air in the fuel distributor and or injector pipes. You can depress the airflow plate to let fuel into the injector pipes with the fuel pumps running.

I would remove the fuel pump relay and jump pins 7 and 8 in the socket. The pumps will run full time then.


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Old 01-25-2011, 12:01 PM
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Join Date: Jun 2002
Posts: 60
priming the system - i turned the key to the on position and the pumps came on getting the fuel moving.

i'll try jumping the pins - are they marked numerically so i'll know which ones are 7 and 8?

do i have to worry about flooding the engine?

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Old 01-25-2011, 12:07 PM
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Join Date: Feb 2005
Location: Cleveland, Ohio
Posts: 1,832
When you turn the key, the pump only runs for a few seconds, you could try turning the key several times without starting the car, and depress the accelerator a few times to get things moving inside the fuel lines. But don't crank till after you've KOEOff atleast 10-20 times
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Old 01-25-2011, 07:55 PM
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Join Date: Jun 2002
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jumped 7 & 8 - pumps running

no start yet - pulled a plug and found it was fouled. will try changing the plugs, charging the battery and giving it another go

any other thoughts would be appreciated
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Old 01-28-2011, 07:04 PM
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Join Date: Jun 2002
Posts: 60
have tried priming multiply times before attempting to start

changed plugs, checked wiring on pumps to make sure they weren't reversed and verified that the fuel lines are connected correctly

engine turns over but does not start
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Old 01-29-2011, 03:59 AM
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Join Date: Aug 2002
Location: Southeastern PA
Posts: 2,970
dtrain, just a thought. Check that the fuel filter is oriented properly. There should be a flow arrow on the side, or the inlet marked "In".

Also, there should be a check valve on each fuel pump. If by chance the fuel pumps or check valves are installed backwards you won't get any fuel flow to the engine.
Fred Hoelzle
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Old 01-29-2011, 07:51 AM
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Join Date: Aug 2005
Location: Toronto
Posts: 394
it isn't possible to install the check valves backwards. i don't believe it's possible to install the filters backwards either.

verify fuel is getting to the fuel distributor, there is an inlet line there, crack it loose and then crank the engine.

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Old 01-29-2011, 05:40 PM
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Join Date: Jun 2002
Posts: 60
have checked fuel filter orientation

check valves came installed on the new pumps and were oriented same as old ones

cracked fuel line at the distributor - fuel started coming out - have not done so while cranking the engine - feared having fuel all over the engine compartment... manual suggested attaching fuel hose to outlet of the distributor and cranking the engine letting the fuel empty into a separate container. was going to check to see if local parts place carried correct female end adapter to do so. will try your method of loosening inlet with some shop rags and see what happens
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Old 01-31-2011, 08:23 PM
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Join Date: Jun 2002
Posts: 60
problem solved. one of the check valves on the new pump was either stuck or bad. happened to order two separately not knowing that the pumps would come with them. changed out the check valve and the car fired right up.

thanks to all who responded.
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