I've got a 98 540i, been running fine. Parked it for an hour and all of a sudden it won't start. Cranks and cranks but won't fire up.
Things I've checked:
Fuel- getting power to the fuel pump, 11 volts while cranking
Crank position sensor - shot the sensor and it's reading ~650 ohms through it
Pulled MAF sensor and tried to start
Haven't checked for spark yet that's the next thing I'll be doing.
So far I've gotten a few ideas on what it could be, I've heard the crank position sensor, EWE could be out of sync, jumped timing (Cam chain guides were done within the last year and a half)
Any ideas or things I could check? Don't want to just chuck money at it for no results
Am I reading that correctly?
You have 11V at the battery?
That likely won’t start.
Measure battery voltage. If less than 12.5V it is dying. Charge it up (either this or new) and try again.
2001 750iL DD74441
Stock
RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1
When it's not cranking it gets 12.5v at the battery, but when cranking it'll drop down to about 10v
Have the battery load-tested. It may be weak, but 10V s/b enough to start it.
Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.
I am guessing your battery may be at EOL (End Of Life). How old is it?
Check the chart below (thank you Timm) In SC you are likely about 80 so a 12.5 is less than 50% state of charge. Charge it up or replace. Try a jump.
You can also try for any codes, but low voltage will cause a no start.
Edit: to Ed’s point, a low charge state will cause sulfation and basically kill it.
2001 750iL DD74441
Stock
RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1
Last edited by TheAngryBear; 10-17-2018 at 08:25 PM.
Tried it with a jump, battery alone is reading 11.7 volts so it's dead as hell. Going to throw it on a charger overnight and see if they makes any difference. Just weird to me it was running fine all day and then after sitting for an hour suddenly won't start
Does the tach on dash display rpm while cranking?
You have voltage at pump, but have you heard it power up/prime the fuel lines?
If not, test fuel pressure at rail.
I actually don't recall if it shows the RPM while cranking. What would that indicate if it doesn't?
Also check sparkplugs, if over 50,000mi-replace them.
If cause of no-start still not found, I would scan for codes.
See if it will start and run for a few seconds on starting fluid.
No, not recommended for use on plastic BMW manifolds, for obvious reasons, too volatile,
use a cleaner spray like carb cleaner, brake clean...etc.
Cranked it and checked for RPMs on that tach, didn't move at all. Going to order the crankshaft position sensor tonight. Hopefully that fixes it.
I’ve had this problem happen a long time ago and it ended up being a broken timing belt. Hopefully this is not your issue but it couldn’t hurt to check that or at least the timing.
Sent from my iPad using Tapatalk
You'll be checking for a long ass time trying to find a timing belt on an M62 engine.
M62 timing chain guides fail famously but they don't look like this when they do.
The dead / killt battery is hugely suspicious. What took out the battery in the first place? Maybe a short? Water in something?
Reading codes would be a great thing to try to do.
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
Update:
Replaced the crank position sensor. I'm getting spark and fuel, but still will not start. Idle air controller is good, it turns freely when I take it out. Tomorrow I am going to check the fuel pressure and probably replace the cam sensor. I tested it and it did not give me an Ohm reading on any combination of the 3 terminals on it. Any ideas?
Dudebro. READ CODES. If you must, just use a generic scanner (not the best by far for a BMW but better than stabbing in the dark).
Typical sudden crank-but-no-start conditions could be:
- Fuel pump death (did you check actual full pressure or just 'gas comes out of the lines'?)
- Crank or cam sensors
- EWS sync
- Other electrical gremlins/shorts/failures including ignition switch, passenger footwell water, ground/power cable connections
Some of the above do not leave codes behind - or in cam/crank case, 'sometimes do and sometimes don't' - but its always best to exhaust that avenue first anyway to see if there's anything the computer is actually desperate to help us with in diagnosing.
Given we know the battery pooped the bed for sure, the EWS sync could have been lost from drastic voltage drop during an attempt to crank. A proper BMW scan tool will retrieve a code pointing directly to this. A OBD Peepee-code scanner might show that code as something a bit more obtuse but still may show it.
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
I did read the codes, nothing but evap emissions code and intake air temp sensor is bad. Neither of which would cause a no start. I'm renting a fuel pressure tester tonight as I think its not getting enough fuel pressure.
Couldn't test fuel pressure because my rail doesn't have the schrader valve. Next thing I'll try is testing compression/cylinder bore wash from trying to start so much
Huh. Does the old 540 have a fitting atthe 3/2 valve maybe?
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
Well, I pulled the plugs, cleaned them, put some oil in the cylinder to help with compression for bore wash, and she tried to start but then wouldn't even pop after that. It sounded SO close to catching
To do list:
- Compression test
- Fuel pressure test
- List of codes
- List of results of the tests for us to view.
I would focus on the fuel pressure and fuel pump/filter, fuel pump relay,
as that seems to be most likely the cause of the no-start condition.
Last edited by MIKYZZ4; 10-27-2018 at 01:34 PM.
How would I go about checking fuel pressure? There is no schrader valve and everything I can find online and in the forums says there is one on the end of the fuel rail but there definitely isn't on mine.
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