I’m baaaack! See previous thread for this weekend’s car drama.
So, here’s where things are at. Any advice much appreciated!
BMW 530i 2002
The battery was replaced yesterday and the car started right up. I drove for about 30 minutes, went out to dinner, and the car wouldn’t start again.
I left her overnight in the parking lot; when I returned this morning she turned right over. I drove for about an hour and parked at home. I turned her off, then she wouldn’t start again.
If I let the car sit for about two hours I can start it again.The idiot lights come on when I turn the key (whether it turns over or not), there are no warning lights, the electronics and security all work.
Why am I able to start the car about every two hours, but not in the intervals? The shop can’t find anything that suggests an alternator or starter engine problems. If it’s electrical, would I be able to start the car just fine every few hours?
Just in a general debugging sense, it could be that some electrical connection got knocked out of whack enough that it makes contact when cold, but not when heated up. So afterwards, it needs to cool down again to make contact.
To be clear, it won’t turn over? It’s possible for lights and accessories to work (excepting headlights) but the starter won’t turn the engine over. Dash lights don’t require much current, a starter draws a couple hundred amperes. Typically this is caused by loose or corroded cables and connections, or a defective battery. Given the history though, in this instance, I’m not sure what it means.
I’d be looking at something marginal, possibly the alternator, that was damaged during the late unpleasantness that is only causing trouble when it gets hot i.e. after it runs for a while. Let it cool down, and it will work for a while again.
The phrase “turn over” as applied to trying to start a car engine has been badly misused by many people for a long time, most glaringly closed-caption narrators, to the point that you don’t know what is meant by it unless the speaker defines the term for you.
Common Tater has the correct sense of it – it refers to the starter cranking or turning over the engine. I usually describe it as a “ruh-ruh-ruh” sound, normally two to four “ruhs” per second. The engine can turn over but then still not start, not “catch and run.”
The other way an engine won’t start is when it won’t even turn over – turn the key to the “start” position and nothing happens (or maybe it makes some sound but still doesn’t crank the engine).
So, the question is, when it doesn’t start, does the starter crank the engine (i.e., the engine turns over, ruh-ruh-ruh-ruh) but the engine doesn’t catch and run, or does it not crank the engine (nothing happens when the key is turned to “start”)?
But back to the problem at hand, whichever the symptom is, it is most likely an electrical or electronic component that has become heat sensitive as mentioned by Randolph. There are many different items that could be at fault, so it will have to be tested while the symptom is occurring.
Oops, to clarify: every two or so hours the car starts normal and strong and I can drive it with no problems, no new and scary engine noises (I drove a couple of hours today). When I turn the car off I can start it again one or two more times, then it won’t start.
When it doesn’t start there are no sounds. The usual lights come on (no scary stuff). There are no ruh-ruhs or beginning to start and cutting out – just silence.
The car will then start again in about two hours. I can drive again, then the same routine with starting.
Okay, this tells us there’s a problem in the starter circuit. First thing to check is battery cable connections, since they had to be handled to replace the battery.
If the problem is not found there, it gets more complicated, and will probably require going to a repair shop.
Missed the edit window:
The starting problem happened on Wednesday; Friday was the Great Battery Stupidity event.
So the car is having the exact issue she was having before I ruined the battery. There are no new symptoms, noises, or changes in driveability (when she starts).
Disconnecting the battery cables is a good starting point.
While the battery is disconnected (both terminals!), check the connections of the grounding cable (the negative terminal) and the slew of wires and connectors on the positive side - look for discoloration or heat damage.
If you get the various dash lights when the key is turned, at least some of the wires going directly to the positive are intact.
Tighten everything (I’d replace the grounding cable, just 'cuz). I’d also replace the starter solenoid, if it can be done easily. I had a wonky solenoid/starter which also made starting something of a craps shoot.
On the plus side - the circuit to the starter and its solenoid (are they still there or have they gone the way of a distributor coil?) are all heavy-duty wires, easily found and traced. It is also a stone-simple circuit.
I haven’t had this particular BMW, but I’ve had several others, many with the same engine (an M54 unless I’m mistaken). Given what you’ve said, the things I would look for, in order of most to least likely is:
Your starter and or starter wire connections are bad (likely the solenoid on the starter) - even if a shop doesn’t find this in the diagnostics, it can still be bad, and is the most likely cause. Removal and testing / replacement is relatively simple with a socket set and a wrench set. I think this is most likely because you said you were having the problem before the battery replacement. But you should go ahead and tighten the battery connections - people often don’t tighten them enough.
An interlock pin isn’t engaged - this could be due to the automatic gear shift position (or clutch if you have one) - the easiest fix is just jiggling the shifter if failure to start happens, although the fix isn’t onerous
The ignition switch itself is going bad - I find this less likely given that you said all the idiot lights come on; some of them would fail to come on if it was the ignition switch, and leaving the key in the “on” position for a while would eventually turn them on and you could start. Given that you say they all come on every time, this may not be it, but ignition switches are a known problem in a lot of BMWs, and they’ve gone south in two different bimmers I’ve had of the early 2000’s vintage. It’s like $20 and you can replace it with screwdrivers and an allen wrench and star wrench set.
It’s probably time to take it to the mechanic. Electrical problems can be tricky to debug. If it’s a connector that’s flaky, running electricity through it could damage it if too much current tries to go through a smaller path than normal.
The simple thing is to make sure that the battery terminals are tight. The BMW batteries are typically in the trunk, so corrosion is typically not an issue. But if the connectors aren’t tight, the car could have trouble starting up.
There is a secret key startup sequence on BMW’s that will put the dash in diagnostic mode. One of the values it shows is the battery voltage. Search for E39 Cluster Test Mode for how to do it.
These symptoms sound just like what would happen with my Ford pickup. The starter worked when it was cold, but after running for a while, didn’t want to work. Let it cool down, starts right up.
To confuse the issue, I had alternator/battery issues concurrent.
Replaced the starter after making sure everything was good and it works flawlessly now. $29, 2 bolts, ten minutes and didn’t even get my fingers dirty. I’ve never had to replace one on any of the BMW’s, so don’t know what your up against. Looks pretty easy on the older ones, though.
Maybe your starter got zapped during the jump-start trauma somehow?
Jennshark - I just read the older thread and noticed this:
Are you sure he tapped the alternator? Tapping the starter is an old mechanic’s trick as well, and it makes much more sense in your described situation. A bad alternator will lead to a discharged battery but, at least initially, you should get the ruh-ruh-ruh of a weakened battery trying to start the engine. A bad starter will make no noise, and a starter that has a “bad spot” or damaged connection may work sporadically. I vote starter.
I concur. The battered RX-7 I drove in college was just as dependent on a hammer as it was the key to get it started. I think the solenoid was sticking, but it’s been a long time.
Hi all: thanks for the replies, I love learning about cars!
So, the definitive diagnosis is the starter. The car is at a highly-regarded BMW specialist garage and the price isn’t too bad ($450).
There’s other stuff to be done, but it’s big $$$ and I’m not going to do it (at least for now). I’ll either drive her until important stuff falls off or sell cheapy cheap and get into a newer Bimmer.
It’s broken and that bugs me, but it will cost $1500 to fix. $1500 isn’t tooooo bad, but I never use the clock anyway so why fix it? Well, just having a broken part in the dashboard annoys me and is kind of lame. But to fix it they have to get behind the dash which is a whole lot of work and they could mess up so many other things while they are there. But I didn’t buy a BMW just to have a broken clock mocking me from the dashboard - everything should work!