1987 325 won't start! Help

[craiggroves91]

So a couple days ago I noticed my fuel filter was making lots of noise, so I started tapping on it and the car then died.

So I just replaced the fuel filter, figured it may be clogged, but the car still won't start.

What could this be?

[SpeicherBimmer]

How bad did the gas coming out of the old filter look? I highly doubt it, but when you tapped it you could have dislodged something that is now stuck in and obstructing the fuel feed...

[craiggroves91]

How bad did the gas coming out of the old filter look? I highly doubt it, but when you tapped it you could have dislodged something that is now stuck in and obstructing the fuel feed...

The fuel looked quite clean. I'm really puzzled.

How could I clear the line?

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[dnguyen1963]

Disconnect the rubber fuel line from both ends then use compressed air to blow from the engine end. Hopefully, whatever got clogged did not travel too far into the line.

[jlevie]

This is the 87, right? If that is the case the noise wasn't from the filter but from the high pressure pump above it. A noisy pump is one that is struggling or about to die. The pump could have failed when you tapped on the filter, or just failed on its own. A failed pump is more likely than an obstructed fuel line.

[craiggroves91]

This is the 87, right? If that is the case the noise wasn't from the filter but from the high pressure pump above it. A noisy pump is one that is struggling or about to die. The pump could have failed when you tapped on the filter, or just failed on its own. A failed pump is more likely than an obstructed fuel line.

yes 1987 325e. That makes sense.

The car has had a terrible idle and has recently started to cut out while driving.

So it could be the pump. How can I diagnose that? Just replace it?

[jlevie]

Tee a gauge into the line that connects to the fuel rail and see what the pressure is when cranking. On this engine it should be 2.5bar. If lower than that the FPR could be bad, the high pump could be bad, or the transfer pump in the tank could be bad. If you have no pressure the high pressure pump is the first suspect.

[craiggroves91]

Alright, so there is no fuel. Just pulled the line off at the regulator and there is nothing.
So its a fuel pump. I'm thinking its the in tank one.

I went under the car and took off the filter and high pressure pump and there is no fuel coming out when cranking.
This means the in tank pump is dead, correct?

[PNWDan]

Alright, so there is no fuel. Just pulled the line off at the regulator and there is nothing.
So its a fuel pump. I'm thinking its the in tank one.

I went under the car and took off the filter and high pressure pump and there is no fuel coming out when cranking.
This means the in tank pump is dead, correct?

If your in tank pump died and the HP pump was still running you could have 2 dead pumps

[craiggroves91]

If your in tank pump died and the HP pump was still running you could have 2 dead pumps

How would I know?

[jlevie]

The in-tank transfer pump is pretty easy to test. To do so, disconnect the high pressure pump so it won't be running dry, remove the feed hose from the high pressure pump and point it into a container, and jumper the fuel pump relay socket. If fuel flows into the container the transfer pump is good.

[craiggroves91]

I've probably already killed the high pressure.
I was cranking it with it wired up

[jlevie]

I've probably already killed the high pressure.
I was cranking it with it wired up

That won't kill a high pressure pump that is n decent to good condition.

[craiggroves91]

That won't kill a high pressure pump that is n decent to good condition.

Okay. So cranking it with the hose unplugged that feed the high pressure pump would tell me if the in tanks is good right?
No fuel poured out when cranking

[jlevie]

That does sound like a dead pump, but to be sure jumper the fuel pump relay socket. Bad timing reference sensors, a DME power problem, etc., could prevent power from being applied to the pumps since the DME controls the relay and only causes the pumps to run when it sees timing data from a rotating engine.