[cparke]

This intermittent starting issue is just weird to me, not sure if this is the battery or what?

Basically, car *usually* starts fine and normal, but occasionally out of the blue (often away from home when car has just recently been driven), starter is having difficulty cranking the engine but does get it to start. Turn off the engine immediately and try to start again and no difficulty cranking. I even was fortunate to have an electronic battery starting analyzer on the car when one of these episodes happened... battery voltage fell to 7.99 volt during the slow crank, but only 10 volt on the immediate subsequent start with normal crank. We are also seeing the Low Battery dash indicator sometimes as soon as we turn off the engine.

Bear in mind, these restarts are only like 20 seconds after the slow crank, no way the alternator is providing any useful charge to the battery this immediately! Battery testing is also inconclusive; I have a 100-amp load tester and it is putting out around 450 CCA. Alternator seems to be good, voltage stays at 14V even with all accessories running, though I have not checked the diodes. Battery is 2 1/2 years old, a 90-AH 800 CCA Napa Legend model, and was it registered and coded in the ECU correctly when installed. It seems to charge pretty quickly after these episodes when I put it on the charger, not like it really was low.

I'm wondering if maybe this is the starter or IBS? Does starter normally vary in how many cranking amps it needs from one start to the next? That could explain some of this. IBS charging program has also always concerned me; what if it's wrong and undercharging solely due to age? I'm very tempted to re-register the battery even though its not new and see what that does? Or maybe IBS is helping by detecting the slow crank in progress and shutting off accessories to allow the crank (and subsequent crank) to succeed?

Parasitic drain seems unlikely since this has never happened (as far as I have noticed) on an initial start in the morning, always away from home or restart upon returning home. More like bad alternator in that respect but where's the proof in that? Also because these episodes happen randomly after good starts and driving, it's hard to tell if recharging the battery helps, though the problem does seem to go away for a few days or weeks after doing so since the battery is certainly at maximum strength temporarily.

Bottom line, like the heading, I'm confused if this is all just a sign of a failing battery in the E90 3-series cars, or rather something more serious?

Thoughts and advice appreciated.

[Konrad5288]

My thoughts. Yes it could be the battery. But when a starter is going bad it can do this. And with it not cranking then cranking fine-probably not the battery. I’d say it’s the starter or starter wire. It’s almost definitely a wire shorting out somewhere regardless. I just had an exposed wire on a tail light that was draining the battery overnight sometimes. And causing slow starts. Figured it out because my truck wasn’t charging as good with the lights on. I even went as far as change alternator cause I thought the alternator was bad. That’s a telltale sign the alternator isn’t putting enough amps out. It should’ve been changed anyway the truck has 190,000 miles on it. And the problem was a lot easier to diagnose once the new alternator was in with the same symptoms. But in reality, it was just an exposed wire shorting into the frame. Took 5 min to fix it. Luckily, it didn’t start a fire or something.

The solenoid or starter motor itself could be shorting out and causing the extra draw. A lot of times you’ll get a crank or no crank from a bad one but every starter is different.

Try this. When it’s acting up. If you can get it to. Can you reach the starter with a hammer? Have someone crank the car. While it’s cranking slow hit it with the hammer a few times and see if you can get it to start cranking correctly. you don’t have to whale on it just tap on it. If it is shorting out when you hit it with the hammer, in theory it can move/vibrate the short off itself.

Don’t ruin your car but maybe try starting it multiple times after you ran it awhile(since that’s when you say it happens most often)until it cranks slow that one time and be ready to tap it.

Have you ever seen someone with the bad starter that’s not working get under their car and hit it with something and then it cranks that’s what’s happening a lot of times. They are moving the wires a bit inside and that allows enough current temporarily to start their vehicle. They don’t have to do that all the time either. A lot of times it’ll work for a while and then go bad again. Just like in your case.

Other than that only way, I know how to check a starter is to take it off and take it over to AutoZone and have them test it. And if you do that have them test it a few times if it’s an intermittent problem.

I’ve seen problems like this, just from the starter wire not having a good connection too. Its a normal occurrence on electric motors/pumps. Happens to my snowplow all the time. Try to move the plow and it won’t move or moves slow so I’ll un click it and then I’ll click it again and it moves fine. During the slow movement it still pulls a lot of current. The current just doesn’t make it all the way to the pump. That’s when the wire needs a cleaning. After I clean the wire, works fine. So maybe clean that starter wire at the connection points too. Sand it nice and shiny again.

[cparke]

By starter cable, I guess you mean the ground strap under the vehicle. That was changed about 18 months ago, and it did seem to make the problem go away for a while. So it's still fairly new.

I changed the starter itself 5 1/2 years ago after the previous one suddenly failed. Though honestly that previous starter also exhibited this strange intermittent starting behavior, and the battery was suspect at the time too. The starter is underneath the intake manifold, so it is not easy to reach with a hammer, as the only way to get to it is to remove the intake manifold. Not sure how to know the hammer did anything also because this problem is intermittent.

The car does have around 170,000 miles now. I have not changed the alternator in the time that I've had the car, so I don't know if it is original or not. I frankly do not understand how the IBS can control the alternator's output, there are no apparent electronics in the alternator and it is connected directly to the battery. Besides the battery positive cable, the only other wire is on a plug-in connector with a single wire! That seems a lot more like a sensor wire of some kind.

I did have an issue about 2 1/2 years ago right after I installed this battery when it was new, where it seems the IBS itself began malfunctioning and both would at times throw a code that prevented the car from starting unless the IBS disconnected, and also it either had a short and/or prevented the ECU from sleeping and drained the new battery. It was not the battery, this issue resolved by changing the battery negative cable which incorporates the IBS.

The one other thing I could mention is a recent scan of the ECU revealed a code 2DED in the DME module. This is something power-related, I'm not clear exactly. but it could just be a response to the extremely low voltage experienced during the slow start.

The auto parts store is giving me a free battery exchange without even testing the battery themselves and despite the fact it is supposed to be a pro-rated warranty and I am supposed to pay something. A stronger battery may be enough to abate this for a while, but if not then I'm looking for what else could be the cause!

[Efthreeoh]

Sometimes batteries just go bad far earlier than there warranted lifespan. If you are getting a new battery for free, then good enough.

[cparke]

Originally Posted by Efthreeoh

Sometimes batteries just go bad far earlier than there warranted lifespan. If you are getting a new battery for free, then good enough.

If the problem finally goes away.

But the history of the time that I've had this car, including after I bought this battery new, is the problem has been there 80% of the time. So while I'm hopeful a new battery will help, but I don't think it is the root cause, and I expect the problem will be back soon if not immediately upon replacing battery.

The weird thing is immediate subsequent starts do not display the starting issue. Frankly, that's scary to try (it almost didn't start away from home and now you're intentionally turning off the engine to try starting again), but surprising that that it don't happen.

Ruling out battery, where do I look next?

[BRG_N54]

Originally Posted by cparke

Ruling out battery, where do I look next?

One quick and easy way to gauge the health of your electrical system is to open up the hidden menu on the instrument panel and monitor voltage in real time, with the car running. It will show if your voltage regulator/alternator is not doing it's job, and I think you can leave it displayed as you start and stop the engine to see the drop when the starter engages.

[cparke]

So the idea here is the voltage should be at all times >=13.5volt once the engine is running? Couldn't I also monitor that easily through the cigarette lighter port with a scope or analyzer that graphs the voltage (after the engine starts)?

[BRG_N54]

Originally Posted by cparke

So the idea here is the voltage should be at all times >=13.5volt once the engine is running? Couldn't I also monitor that easily through the cigarette lighter port with a scope or analyzer that graphs the voltage (after the engine starts)?

It should be between 13.5V-14.5V, as it can be in an overvolt state also. I would trust the onboard function to be more accurate than a lighter plug, plus it's free and does not require any other tools.

[cparke]

Originally Posted by BRG_N54

I would trust the onboard function to be more accurate than a lighter plug

Yes but I have to keep watching it and I can't get a graph or recording without an awkward camera setup and video review.

Maybe if the cig lighter isn't accurate enough then I could connect the scope under the hood at the alternator or charging/jump posts or in the trunk at the battery?

[Konrad5288]

What I was saying with the starter cable is the positive wire to the starter. It might have a flat spot. The starter grounds to the engine. If the engine ground was bad you’d be having other electrical issues too. I thought about it a bit today and that makes the most sense. So it happens occasionally after the car has been warmed up. car warms up and the air outside is colder that causes condensation. The condensation could disrupt the electrical current If the connection between the starter and cable isn’t great. Or the connection from the cable to the positive terminal is not great. I’d say clean up both those connections and would suggest putting a little bit of dielectric grease on there for good measure even though I never use it. And it should be good. Or maybe try to re-create the condensation. Grab your hose spray it on the starter wait a minute and try to fire her up.

A lot of times, electrical issues will be exaggerated with moisture added into the equation Since water, conducts, electricity. when you go to crank it, and a crank slow, you got a little short, which heats up the connection burns off the water then you go to start it again no more water to disrupt current and fires up fine.

Does it occur more often when it’s raining outside? That would be a good indicator also.

I’m just saying you’re having a cranking issue and you haven’t even checked the starter or the cable going to it.
Slow crank in order-battery>alternator>starter>some other electrical issue
No crank in order-battery>alternator>starter relay/fuse>starter>ignition switch>seized engine=some other electrical issue

Some other electrical issue would be the least of my worries on a slow crank or a no crank😀😉unless the code checker told me otherwise.

[Konrad5288]

Plus anytime you get more draw as you described in the OP you have a short. A battery is a simple energy device. It doesn’t magically have more power 20 seconds later it has a better current flow 20 seconds later. If you heat it up 10 degrees it will have more power, but if that was to happen instantaneously you wouldn’t have a battery anymore, it would now be called a bomb. Get out of there it’s probably gonna keep rising and your car is about to get an acid shower.

Sorry for writing so much but with that much extra draw, the culprit almost has to be the starter or cable. Nothing else really draws enough power for it to fall off so much. The wires aren’t big enough to carry that much. They would usually burn up a bit and you would smell them

[BRG_N54]

Originally Posted by cparke

Yes but I have to keep watching it and I can't get a graph or recording without an awkward camera setup and video review.

I think you are over analyzing my suggestion. Get in the car, and drive it around a bit with the voltage display on. It's right next to the other gauges you should be looking at while driving, you know, speedometer and such. If it reads in the correct range, then move on, but at least you will be able to positively make a diagnosis on one aspect of your car's electrical system, without introducing any more unknowns into the system.

Originally Posted by cparke

Maybe if the cig lighter isn't accurate enough then I could connect the scope under the hood at the alternator or charging/jump posts or in the trunk at the battery?

I would recommend the jump points, not the trunk. Or, just look at the display while you start the car? Was just trying to suggest something easy and quick, YMMV. Best of luck with your electrical gremlins.

[Konrad5288]

Oh and on your other concern with IBS. There is no way that would cause starter to receive less power. The starter is connected directly to the battery and draws whatever current is needed when the starter circuit opens. The starter circuit is essentially only an on/off switch. It’s goes to one wire that tells the solenoid if it’s time to draw current or not time to draw current . It doesn’t regulate current flow.
nothing controls the current except the starter itself or if there is a short in the direct line between the starter and battery. There is no fuse between them on most vehicles either. If there is. I haven’t seen it. There are only fuses in the starter circuit. Why is there no fuse? Think about it. How many cranking amps does the battery have? Starters need a lot of amps. Not sure if rated CA automatically goes to the starter or not. But that’s how many amps can go to the starter if needed and is a lot more amps than any standard fuse can handle.

[cparke]

Ok, first of all dielectric grease, by definition, does not conduct electricity and people usually use it on spark plug boots to seal off outside moisture, not to aid in conducting electricity, so I don't know where I'd use that appropriately on the starter positive cable.

Now, it sounds like you're not very familiar with these cars, and giving general advice. Which is fine. But the starter positive cable on this car is live always (starting is switched negative) and the connector is a Y, look at the photo here from Pelican Parts tech article:



The line comes from the charging post junction area to the starter and then comes back up through the Y and goes to the alternator. So if there is a connection issue, it will likely affect the alternator output too. It's a very low guage cable running from the battery in the trunk at the rear right up to the engine bay and then over the engine and down below the intake manifold. The only way to reach it without removing the intake manifold is to stick a metal pole through the intake manifold onto the connector, which is not safe to do unless you disconnect the battery negative first.

I have not noticed rain or cold temperatures making a difference. But I think recording the alternator voltage at the battery in the trunk might be a good idea and will diagnose the starter cable sufficiently at the same time. Though the suspected short may be in the starter itself and only happens when the starter is engaged. Or maybe it is an arc with the Y connector when the starter draws the current?

[Tambohamilton]

Originally Posted by cparke

...
Now, it sounds like you're not very familiar with these cars, and giving general advice. Which is fine. But the starter positive cable on this car is live always (starting is switched negative) and the connector is a Y, look at the photos here:
...

Apologies, I haven't read all the thread, but this jumped out at me. How can the negative be switched? The negative is through the fact that the starter is bolted to the engine block! The positive is what's attached to the starter solenoid. You're right that the positive cable is permanently live, though.

Also from your first post; the IBS is not your issue here.

I'd point the finger at a failing starter, or maybe bad earth strap or positive cable (anywhere between the battery and the starter, but most likely at the connections on the wall of the battery box)

[Konrad5288]

First off. I don’t know the correct way how to use dielectric grease. I’ve never used in my life. I was just suggesting it because that’s what everybody suggests to me. When AutoZone installs a battery, they put that grease all over the nubs. I’ve seen him do it that way I don’t know if it’s right or not. So I don’t know.
I said right in that post I don’t use it I was just suggesting using it Because any train mechanic is gonna tell you to use electric grease on electrical connections. I’ve seen videos where people put that grease all over their connectors, and then plug them together.

But Yes the starter is just like any other starter. Foreign or domestic. All the same. But if there is condensation getting in there it will be gone when running as explained in my post. With the car running and current constantly flowing you won’t get condensation in there. There may be a really small disruption in current but instead of burning off(just as an example)100 atoms of H2O at once the constant current is burning off 1 atom at a time. So you won’t be able to see it on your gauging device. Condensation will accumulate when there is no current to evaporate it or when your car is sitting. That’s why it would only effect your car at first start up after sitting for a bit.

I say spray it with the hose. You could also test the alternator current with it running and spray the starter with the hose while it’s running.

But also if your DME is located where mine is that wouldn’t be very good idea. It was a general idea. Maybe take a cup of water and dump it on the starter while running and scanning the alternator current. Or take a spare radiator hose and route it over your starter and dump water on it that way. It’s like you’re putting in a lot of time trying to figure this out and it would be a very easy test just to make sure the connection was good on the starter with water. Because I can almost guarantee you the starter or one of those big wires going to it is the problem and it has nothing to do with any other electrical system in your car.

You can also use the same test on a battery to make sure your battery connections are good. Obviously, nobody’s going to pour water on a battery that’s sitting in their trunk. you ever think your battery connection might be bad and your battery is under your hood dump water on it and you can check the connection to make sure it’s good that way. A lot of times you’ll get a spark if there’s a bad spot on the battery connection. I wouldn’t expect a spark on the starter though in your case. But when the connection is really poor, you’ll for sure get a spark.

[GSB]

Originally Posted by cparke

This intermittent starting issue is just weird to me, not sure if this is the battery or what?

Basically, car *usually* starts fine and normal, but occasionally out of the blue (often away from home when car has just recently been driven), starter is having difficulty cranking the engine but does get it to start. Turn off the engine immediately and try to start again and no difficulty cranking. I even was fortunate to have an electronic battery starting analyzer on the car when one of these episodes happened... battery voltage fell to 7.99 volt during the slow crank, but only 10 volt on the immediate subsequent start with normal crank. We are also seeing the Low Battery dash indicator sometimes as soon as we turn off the engine.

Bear in mind, these restarts are only like 20 seconds after the slow crank, no way the alternator is providing any useful charge to the battery this immediately! Battery testing is also inconclusive; I have a 100-amp load tester and it is putting out around 450 CCA. Alternator seems to be good, voltage stays at 14V even with all accessories running, though I have not checked the diodes. Battery is 2 1/2 years old, a 90-AH 800 CCA Napa Legend model, and was it registered and coded in the ECU correctly when installed. It seems to charge pretty quickly after these episodes when I put it on the charger, not like it really was low.

I'm wondering if maybe this is the starter or IBS? Does starter normally vary in how many cranking amps it needs from one start to the next?

I bought a brand new Interstate battery that has full cranking power but only reads 11V after a full charge. That's a bad cell. And it really should be replaced because this car does NOT like low voltage. It's also straining the alternator as the engine is running.

Nevertheless, in your case, it's useless to monitor the voltage while the car is running. A bad start means that you have low voltage before you start the engine. As for the intermittent nature of your starts, while the battery may be going flakey, it's just as likely to be the starter, solenoid or wiring.

From the Pelican Parts image below, you can see the solenoid sitting on top of the starter motor. It's the solenoid that switches the massive 150A+ to the starter. It is fairly common for the contacts in the solenoid to go bad, sometimes intermittently at first. Every time it switches those massive currents, the contacts arc and become a little more pitted and corroded, until one day, they struggle to provide good contact. That extra contact resistance creates heat that causes further damage to the contacts and so it goes until they burn or fail altogether.

Also, inside the starter, you can have the brushes going bad for similar reasons. So if your battery, wiring and connections are okay, your starter/solenoid might be on the way out.

[cparke]

The actual starter/solenoid looks more like this photo from the auto parts store.



The exposed brass wiring on the front running down from the solenoid to the starter is what the current flows through to run the starter when it is switched on by the solenoid. I've separated the starter motor from the solenoid before, and I have a new starter already too for the day it fails and needs to be changed. Like the ground strap, I think they make the connections like this because the wires are expected to get hot when the starter runs.

I may be able to see and inspect this wiring with a flashlight looking through the intake manifold. Still we're looking for an intermittent short during starting that is so severe the battery voltage drops to 8V when it happens. And it happens when the engine is warm, not when it is cold!

[scotthilly]

I have a similar issue. Cold starts typically fine, occasionally warm starts take an extra beat.

Other forums for N55’s and N54’s have said the isssue was the starter, fuel pressure regulator, or the high pressure or low pressure fuel pump. It could be one of these - from what I understand, the LPFP changes how much it works depending on engine temperature. Therefore, as it’s wearing down and getting old, it’s not doing the its job correctly and causing an extra few cranks.

I don’t have a mechanic’s mind so I could be totally off base - but that’s what I’ve found after doing heavy research. Hope that helps!

[GSB]

Originally Posted by cparke

Still we're looking for an intermittent short during starting that is so severe the battery voltage drops to 8V when it happens. And it happens when the engine is warm, not when it is cold!

I don't think you're going to find a short except internal to the battery or starter motor itself. A battery and starter cables are capable of delivering hundreds of amps that can easily blow a short to smithereens. It is possible for the commutators inside the starter motor to smear and short to each other, causing a higher current draw, but that theory is unlikely if the very next start, 20 seconds later, doesn't share the same symptom. I still think your battery is a major culprit. When exposed to vibration, physical stresses, and temperature stresses in an automotive environment, or sudden discharges at high current, the plates inside a battery will physically twist and bend. It's not uncommon for the plates to temporarily contact each other in a compromised battery, creating an internal short that will most certainly drop the voltage and cranking capacity until the plates move again.

[cparke]

Originally Posted by GSB

I don't think you're going to find a short except internal to the battery or starter motor itself.
... I still think your battery is a major culprit.
...
It's not uncommon for the plates to temporarily contact each other in a compromised battery, creating an internal short that will most certainly drop the voltage and cranking capacity until the plates move again.

This I tend to agree with you, and this seems the most plausible explanation that I've seen here yet. A small short in the battery itself would cause a slow drain in charge (which I may also be experiencing) and could intermittently cause the huge voltage drop to 8V while starting?

Additionally, it does seem that if I charge the battery myself, the problem goes away for a few days. Of course, I always charge the battery after this happens because I don't want it to happen again and be stranded either. At any rate, the car also cools and the battery rests once it is home, changing conditions. However, maybe I should stop the charging at home and see if this can happen on a cold start too?

[GSB]

Many strange things can happen to a battery. A "hard short", when two plates contact each other, can be fairly catastrophic, resulting in overheating that can even lead to an explosion. A "soft short" occurs when the normal shedding of material from the plates creates a sediment that builds up and begins to reach the bottom of the plates. Small chunks of the plates can come off in older or defective batteries too, and these may move around and get in bad places.

But didn't you mention that your symptoms predated your current battery?

Like Konrad5288, I'm still skeptical of your starter/solenoid, though you mentioned that you'd changed that out too?

Also, when you used the battery starting analyzer and the battery voltage fell to 7.99V during a slow crank, where, exactly, was the analyzer connected? At the battery terminals, or at the engine/starter? That can make a massive difference to the readings because of resistance drops and potentially bad connections along the way.