M54 no start problem, ideas?

SBBimmer · #1 01-30-2022, 07:35 PM

I think this is fuel system related, but I have exhausted my diagnostic skills. Backstory below, but I have run codes on my Foxwell and nothing comes up, fuel pump produces a generous flow when cranking (checked at top of tank), there is fuel present at the fuel rail schrader valve after cranking, battery is topped up, starter motor sounds fine, but I crank with no ignition. However, the issue started as a loss of power situation.

BACKSTORY: a little while back i stupidly ran my tank very low on fuel. I made it to the station and put fresh fuel in without problem. About 3 miles later, nearly home, going up a small hill there was hesitation, but I made it into my driveway. I ran codes and didn't see anything. The next day the car ran but clearly was losing power so I parked it and figured maybe I had stirred up gunk in the bottom of the tank and should change the fuel filter. I did that (getting the underbody protection on and off without a lift was a bitch, but the filter itself seemed pretty easy). Quick release fittings came right off and snapped back on, I started the car and ran it for several minutes and saw no leaks so I shut it off and closed the bottom back up. Dropped the car, started it and moved it 30 feet. Then a couple hours later I went to drive it to the store and after it started the revs immediately dropped and it stalled out. It did that a couple times and then refused to start. Ran codes again, still nothing.

This is my 2005 3.0i automatic which currently has 101K miles on it, fuel filter I took out was original, but the car was running great for the 6K miles I've owned it.

Any help greatly appreciated as always.

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puddinboo · #2 01-30-2022, 07:49 PM

Have you tried unplugging MAF sensor to see if it will run?

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SBBimmer · #3 01-30-2022, 08:37 PM

Thanks for the idea, definitely worth trying, but I just did it and no difference, cranks but doesn't start. I was hoping that was it, this not knowing where to look drives me crazy.

Bdc101 · #4 01-30-2022, 09:36 PM

By "loss of power situation" what do you mean exactly? Did the battery get drained to the point where it wouldn't turn the starter? If so, check to see if the immobilizer lost synchronization with the EWS. It would provide the symptoms you have.

SBBimmer · #5 01-30-2022, 09:45 PM

Quote:

Originally Posted by Bdc101

Did the battery get drained to the point where it wouldn't turn the starter? If so, check to see if the immobilizer lost synchronization with the EWS. It would provide the symptoms you have.

There was no problem with the battery. It sat some and got cranked a bunch while working on it so i threw a trickle charger on and topped it up so i know it is full voltage, but it was never really down, it always cranked fine.

By "loss of power" I mean the engine was hesitating like it wasn't consistently getting fuel and the car didn't have it's normal performance power. That came first, then it was stalling out after starting, now it won't start.

puddinboo · #6 01-30-2022, 10:03 PM

Did you take the spark plugs out,to see if their soaked in fuel,maybe flooded .

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SBBimmer · #7 01-30-2022, 10:29 PM

No, I haven't looked at the spark plugs (I was stuck on it not getting fuel). Not sure I'll have time tomorrow but I'll try. It has sat for some longish periods between attempts at starting it, would that make any difference? I have some new spark plugs I've been planning on installing. Any reason not to put them in if I have the old ones out?

80stech · #8 01-30-2022, 10:30 PM

You need to check the fuel pressure at the rail, generous flow means nothing.

puddinboo · #9 01-30-2022, 10:38 PM

I would throw the new plugs in anyway. Easy job. Sitting for a long period of time,the fuel should evaporate. It still sounds like either its flooding real bad or not getting fuel to start.

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Effduration · #10 01-31-2022, 12:20 AM

Spark, fuel, air...

I would confirm you have spark. Pull a coil and a spark plug, put them together and see if you get spark when cranking.

Borrow or buy (harbor freight) a fuel pressure tester...you need 50 psi or so at the rail when you prime/crank...Good tool to have..

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