BMW 325i Won't Start

CLEARMEADOW

MEMBER
1932 BMW 325

Hello,
I love my BMW 325i, except that it is giving me hell currently. It has been having some trouble starting (sometimes needing to crank it 2-4X for 10 sec intervals before starting) and today, after starting it briefly then leaving it for 20 min, then trying to start it again, it turned over but didn't fire. Tried many times with no luck, let it sit, thought maybe it had flooded so I took out the spark plugs and cleaned them and replaced. Still no luck.

I know to check for a spark, will as soon as someone else is around. But don't know how to check for fuel pressure, coil etc. Any other reccomendations before I bite the BMW repair cost bullet and take it to a mechanic?

Your assistance is sincerely appreciated

6 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

You didn't mention year or mileage but it sounds like the fuel pump. Depending on production date the pump was in the tank from 9/88. When it doesn't start, take the rear seat bottom up and thump the fuel pump (on the passenger side) with a screw driver handle or I just use my fist, if it starts replace the fuel pump and the main and fuel pump relays.

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Thursday, September 13th, 2007 AT 1:42 AM

CLEARMEADOW

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5 POSTS

Thanks for the response, I will give that a try today. The car is an '87 with 211k miles on it.

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Thursday, September 13th, 2007 AT 10:37 AM

DOCHAGERTY

MECHANIC
9,601 POSTS

For an '87 car, try replacement of the main and fuel pump relays first. The earlier cars have the fuel pump outside the tank.

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Thursday, September 13th, 2007 AT 11:11 AM

CLEARMEADOW

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Is there a main relay that is different from the fuel pump relay?

Also:
I had thought my car was a 325i because that is what the last person that owned it claimed it was, but I just figured out (because of the reduced redline and name on the back) that it is just simply a 325 (with an eta engine). In case this is pertenant to anything.

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Thursday, September 13th, 2007 AT 3:27 PM

CLEARMEADOW

MEMBER
5 POSTS

Ignore the last question, I got a repair manual and realize that there is a main relay as well.

Now for the update:
I checked for fuel pressure at the inlet to the injector and found it was pressurized, tried starting (nope), checked spark plug 1 for spark and found it was sparking, then took out and put back a large black relay in the fuse box (later found out this is my wiper control unit, so I'm sure that did a lot of good), and turned the key and started it up to my complete suprise, then drove around for a bit to replace the 30X attempted starts battery drain.

So, I know that something is in the process of going. But am completely boggled as to what it is. I read something about a "crank sensor" that someone else was having trouble with that also caused this intermittent starting issue.

Could this be the problem? What would cause it to start up sometimes, and not at others?