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Posted

Out driving this afternoon....stopped for a 15-20 minutes and the Birkin would not start...I thought it was flooded at first but there was no gas smell...gas tank was full...It looks like the fuel pump is beside the the left rear wheel with a filter attached. I sometimes hear the pump run when I start the motor... no sound now.

The car has a yellow top Zetec with Raceline throttle bodies. The fuel pump fuse is ok.

 

 

Any other ideas before I replace the pump? If replacement is the answer any suggestions for a fuel pump?

Posted

Try starter fluid or a little gas thru each spark plug hole. If it starts then its a fuel issue. You can also disconnect the fuel line at the fuel rail, put it in a bottle and cycle the ignition a few times. If there's fuel then the pump is flowing, but may not have enough pressure to start the car. Also try switching out the fuel relay for a known good one.

Posted

Strange....after 4 hours on the Battery Tender...the fuel pump ran...I did not try to start it as it would have terrified the tenants in the apartment above the garage. This morning it started first turn...I have an Odyessy PC935 battery...could it be that I flooded the car and then ran the battery low trying to restart it....the battery got weak but was not having any trouble turning over the motor. The battery is abut 2 years old.

Posted

Sometimes the starter can still turn over the engine but the battery voltage is too low for the ECU to function. I've seen this before in Miatas.

 

I charge my Odyssey battery at least twice a year for 24 hours with a charger made for AGM batteries. Its in its sixth year of use in the Caterham. The Westco AGM battery in my Miata is 9 years old and still going strong. I also give it semi-annual charges with the same charger.

Posted

Since I may not drive for a week or two in the winter...I keep it plugged up to a Battery Tender while it's parked...Could the battery been so low it would not run the pump...or was it the ECU not working that kept the pump from running?

Posted

I had this symptom in my Birkin when new--when the car was assembled (not by me) they did a lousy job of trimming the fuel line. Crumbs of rubber found their way into the pump. Sometimes the pump would slow down, and a couple of times it stopped altogether.

 

I replaced it with a similar pump from the auto store. Found a near match in a kit intended for upgrading old pickup trucks to electric pump. Don't remember the brand, it was over 10 years ago.

Posted

I spoke too soon...after the car sat all week on the Battery Tender...no sound from the fuel pump and no start. I checked the fuse and relay.

 

Any thoughts?

Posted

I would check for voltage at the pump, if there is power at the pump then I would say the pump is bad. If there isn't voltage then I wold check the pump wiring for continuity.

Mike

Posted

My electrician tracked the problem down to a broken wire between the pump and the fuse block...and the fuel pump fuse block was dead. We reran the wire and used a spare fuse block. The car starts and runs...the fuel pump seems to keep running. A drive in the morning will be the test.

Posted

After thinking about this problem...it does not seem that the fuel pump lead wire AND the fuel pump fuse block would go bad at the same time...Is there a relay that turns off the fuel pump when pressure is built up at the fuel regulator? We have the Birkin diagram but do not see a relay. The fuel pump always ran for a few seconds at startup...built pressure and switched off...does not shut off now.

 

It might be the fuel pressure regulator but that would not explain the dead fuse block.

 

Any thoughts?

Posted

Mike,

 

The ECU is programmed to run the fuel pump for a few seconds, shut it off, and restart the pump full time when the engine is running. This is the normal way, even on your Mercedes (if you still have it). If your electrician wired the pump into the fuse block and fuel pump directly, thus by-passing the ECU, then the pump will run all the time.

 

Glad he found the broken wire and bad fuse block. Chasing electrical stuff is a fun game.

 

Dale

 

Are you going to come over to Oklahoma for the get together weekend?

Posted

Mike,

 

The fuel pump is a high-draw item and should have a relay in the mix. To reiterate Dale’s post, the ECU on EFI cars usually powers the fuel pump relay. During start (pre-start: ignition key to on) the fuel pump should prime the system and then shut off. Once the car is started (engine running), the fuel pump should turn on and operate until you shut off the ignition. Here is a common electrical schematic for an electric fuel pump.

 

85: power to the relay from the ignition

86: ground for the relay (ground for 85)

30: power from the battery (fuse block)

87: power to the pump

 

When power is applied to 85 via the ignition, a connection is 'powered' closed between 30 and 87 allowing power from the fuse block to be routed to the pump.

Posted

That's the problem...the wire from the fuse box to to the fuel pump showed a break somewhere in the wire loom...and the fuse block was dead. It doesn't make sense that there were two failures.

Does the ECU switch off the fuel pump at the fuse block? If so why is the block dead when the key is on...every other fuse block was hot.

Posted

This is starting to make sense...the must be a relay somewhere that has failed thereby killing the fuse block...in the fuse panel there is not a fuel pump relay.

Not sure why the line from the fuse box to the fuel pump was dead.

Posted

Mike,

If you can locate the “original” relay for the pump, check the ground (85). This may be the issue. I sent you a pm; call if you want.

 

Shane

Posted

Using a mirror I was able to find 2 relays hidden under the dash ... I have new ones but haven't had a chance to try them...this should take car of the problem.

 

I appreciate the help.

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