Turns over (and over, and over), but won't start??

[rcbrown23]

Hey guys... here's the deal. I picked up a 94 540i a few months back after it was in a small front end fender bennder. Got it cheap, with the intention of fixin it up, but it's taken longer than I anticipated. Finally got the front end parts put together yesterday, so I went to try and start it last night, and it wouldn't.

It sat in someone's driveway for over a year without being started, but it DID start after about five minutes of pumping, jumping, etc.

Since then, it's sat in MY driveway. I changed the oil, put in premium gas, and started it about once a month to drive it around the block. No problems whatsoever.

Well, I got lazy, and it's been sitting for around 3-4 months, and now it won't start. It turns over like , but I don't think it's getting any gas. I pumped the sh!t out of it, and I can't smell a taint of gasoline anywhere. Any idea's?? How could it start just fine all the other time's, and it's just been sitting and suddenly won't start?

Fuel pump? can that go out just like that?

Argggg...

[glen-sj]

The fuel pump on my 92 525 went go without warning at the parking lot of OSH with no prior warning.

[BillionPa]

i would do a full fuel system tune up, new pump, new filters, new gas. and by new gas i mean get all the old stale gas out, ALL OF IT.

with the length the gas has been in there, i would be surprised if it did start.

also flush the coolant and change the oil again.

[rcbrown23]

with the length the gas has been in there, i would be surprised if it did start.

Yeah... but it sat for MUCH longer (over a year), in horrible outside conditions without being started once, and when we went out to try, it started?

I did flush the old tank and put in ALL new gas, and it started just fine every time... untill now (when I actually need it to) of course

[DaveVoorhis]

Have you got spark? Is fuel going into the cylinders? Knowing the answer to these questions is the starting point; otherwise it's all guesswork.

[rcbrown23]

Have you got spark? Is fuel going into the cylinders? Knowing the answer to these questions is the starting point; otherwise it's all guesswork.

How do I check? take out a spark plug and look for a spark?

How do I know if fuel's getting to the cylinders?

I'm no mechanic, but if someone could explain these things just a bit, I'm sure I can handle it.

Thanks in advance.

-brown



EDIT: I'm remembering an old car I had, and when I put the key in the ignition, but didn't start it, I could hear the humming of the fuel pump for a few seconds. Should I be able to hear that in this case? (My first BMW, sorry for the newb questions)

[DaveVoorhis]

How do I check? take out a spark plug and look for a spark?

Yup. Pull a plug (I'll assume you know how to do that -- if not, call for a tow), hook the plug lead to the plug and lay it on the head so that the threads are securely grounded. Shade the plug so you can clearly see the gap between the electrodes without sunlight or whatever washing out the view. Try to start the engine. A fat, blue spark should jump between the electrodes.

How do I know if fuel's getting to the cylinders?

With the plug still removed (and set well to the side, but grounded, so it's not going to zap you, be operated without being grounded, or ignite you with what we're gonna do next) put your hand over the plug well and try to start the engine. Engine compression and vacuum should alternately try to suck your hand in or pop it off the hole, like FooP! FooP! FooP! Afterward, your hand should be slightly damp with fuel.

EDIT: I'm remembering an old car I had, and when I put the key in the ignition, but didn't start it, I could hear the humming of the fuel pump for a few seconds. Should I be able to hear that in this case? (My first BMW, sorry for the newb questions)

Not necessarily. I was able to hear my E28, can't hear the pump the two E34s I've had.

[rcbrown23]

Awesome, thank you Dave. I'm off to work right now, but I'll try both those things tomorrow and see how it goes.

Any other suggestons/theory's would be great, too.

-brown

[rcbrown23]

Alright... I was about to go out and check for a spark and see if it was getting fuel.

Well.. I figured I'd give it another try before I went through the trouble, and sure enough, it started for about 2 seconds. I KNOW I could've kept it going if I was ready for it, but I wasn't expecting it to start.

I'm now thinking it's just bad gas, but I'm not sure. Since it DID start for a second, that means it IS getting spark and fuel, right?

I'm going to drain the tank, run up and get some gas and octane booster or something, and try again.

Any help would be much appreciated.

[DaveVoorhis]

Did you try it again after it ran for two seconds? The problem could well be intermittent, or you might have water or other contaminants in the tank.

Gas usually won't go so bad in a year that it won't run at all, but sniff what's in the tank. If it smells like gas, it's probably okay to run, unless you've got water in the tank. If it smells like turpentine, siphon it out and replace with fresh stuff. Octane booster won't help; ether (engine starter) at the intake (with the air filter element taken out) might help, with a small risk of a backfire blowing your AFM to smithereens.