[scottalexander]

I'm in a position to make you an offer.

First, a little context before the offer.

I was working with a guy on this forum many months ago. His battery was going dead because the water pump was running continuously. After the car was shut down the water pump would still run and kill the battery.

What he would do is unplug the water pump at night and then the battery had enough energy in the morning to start the car.

Now he discounted the water pump was bad because it was only 2 years old and didn't have many miles on it. What he did was buy a new water pump. Before he installed it, he connected the new water pump up to the electrical harness and much to his amazement the water pump didn't turn on. Good news. He knew that if he installed the new pump it was going to function properly.

Here's the offer:

We can run a similar test at a low cost.

I have a water pump with 45,000 miles on it sitting on my shelf. I can give it to you for free. The cost to you is shipping cost from Philadelphia to where ever you are.

Why do I have this water pump?

I wish I had a dime for everyone on this forum who's water pump died. I wanted to avoid that event. Being paranoid, last year when my car hit 45,000 miles I proactively swapped it out for a new one.

Some say the circuitry in these water pumps overheats and the board cooks so the pump fails. Another hypothesis is the water pump being covered with oil doesn't help and the oil makes its way to the electronics. Also, many don't change their Pentofrost NF and claim that doesn't effect pump operation.

 

[AdamJC]

Thank you - I really appreciate that. To clarify though, the water pump is no longer going on when I plug it in (that was the case in many of my previous test scenarios, but after replacing the oil sensor that doesn't happen at all). If I plugged in a new correctly working water pump then it also wouldn't (and shouldn't) turn on just like the one I have now. I suppose if I plugged it in with the IBS plugged in and the car started fine that would say a lot. I probably should try plugging in my old water pump in first and seeing if that makes a difference (in case the new water pump is bad and the old one wasn't). Of course they could both be good or both be bad, just like my recent IBS swapping test. What are your thoughts?

 

[scottalexander]

Good thinking.

Run an exercise and plug in the old water pump and see what happens.

 

[AdamJC]

OK, so I plugged in the old water pump with everything connected and the car didn't start (and the pump didn't run). Then I unplugged the IBS and the car started but ran pretty rough - much rougher than the day before. So I unplugged the old water pump and plugged in the new water pump and it was still running really rough. It was colder and rainy, so that could have been why. I also thought maybe there was oil contamination on the plug from the old water pump, so I thoroughly cleaned everything with the electronics cleaner, let it dry (I thought), but now it won't plug back in. Feels a little spongy at the end where the clip would normally snap into place, so maybe I over doused it and whatever gasket is in there swelled up. Everything looks squeaky clean, but I can't get a super close look because the car's on the ground. Hoping everything will snap back together once it fully dries out, otherwise I'll put it back on the stands and inspect closer (the plug is just a tangent I realize). Bottom line, it appears to act the same with both pumps. I expect both pumps are good. It seems unlikely that many new OEM pumps come off the line not working... has to be like a 0.1% thing I would think.

 

[AdamJC]

BTW, I did also test it with both the water pump and the IBS unplugged and it ran perfectly... makes no sense (to me anyway). The difference between how it runs cold and warm is a head scratcher too.

 

[scottalexander]

New Idea:

You are not the first person in BMW history with this problem. While we can't find the solution in the BMW forums, we might be able to find the problem in other forums (e.g. Mercedes).

Next:

Its time to call Pierburg and Continental who makes these water pumps. Which pump do you have?

The Pierburg product managers who work with their knowledge management data base each day know what is happening with your water pump. They can crack this mystery in two seconds.

There was a guy recently on this forum with a transmission problem. His mechanic did a bunch of replacements and it never fixed the problem. The mechanic finally called ZF and they told him the solution. It was a bushing.

Its time for Pierburg to tell us the solution.

 

[AdamJC]

Good suggestion - thanks. I have the Pierburg pump.

Another thought... not to confuse hot/cold vs moisture, but I recall many, many years ago having misfire problems with my old car whenever it rained. It turned out the spark plug wires were bad/old. Could the temperature/weather affect the wiring somewhere here to make the fault mostly disappear as the temperature goes up and humidity go down? BTW, still no error codes except the scan tool recognizes when certain components are unplugged from the BSD system.

 

[scottalexander]

Good point. There could be wiring faults or a water pump harness connector fault.

Next:

You have a Foxwell scan tool and all the BMW forum guys love the model 510.

However, we are at the point were we can't rule out the following.

If we connected ISTA to your car, would ISTA capture a fault code that Foxwell isn't identifying?

We have to run the exercise with ISTA because it might give us a aaahaa moment. Or it might not produce anything new, but worth a try.

I live and die by ISTA and work on the premise if ISTA can't identify a fault, nothing can.

 

[AdamJC]

Thanks. I'll work on the ISTA install. I'm sure i need to buy a cable too. I want to back up my computer first since I was having some issues... I'll get there!

I did send Pierburg an email - might be a bit of a long shot that they'll respond to an end user, but you never know.

 

[scottalexander]

Similar story:

I reached out to Valeo in France last year (the firm that makes my alternator).

The reason I did this is because I wanted to buy a voltage regulator for $30 and everyone wanted to sell me a new alternator for $400. Many places had Bosch voltage regulators, but not Valeo.

I did some research and found the name of the product manager for Valeo alternators. I didn't tell him I was a retail customer.

It took 3 weeks and he told me two firms that will sell me the Valeo voltage regulator.

Better late than never and it was a 5 minute job putting in the new regulator.

We need to find the right guy at Pierburg and he'll help us.

Its going to be funny if we find out Pierburg gets this question 20 times a day.

 

[AdamJC]

Thanks once again for the feedback.

I have a new idea I wanted to float out there (to see if it's crazy or not). The starter has two connections - the main power connection and a secondary connection, which I assumed was to activate a solenoid to engage/disengage the starter with the flywheel. Is it possible it does more than that? Presumably a lot of power is coming from the battery and that gets switched off or redirected at some point and the alternator kicks in to provide power to the battery.

Background - I was keeping the engine revved up today while the monitoring the engine cutouts (it was almost shutting off but keeping running) and I noticed a consistent drop in voltage each time the engine almost shut off (the battery was also low so that may have contributed to the drops). Anyway, it lead me to thinking that the ignition (spark plugs) may be getting most of their power directly from the alternator rather than the battery, and if the alternator shuts off suddenly and temporarily, maybe it switches to the battery, and then back to the alternator causing the shut off. Question - is there something in that connection to the starter that controls power distribution, and if that connection was bad, could it cause power interruptions from the alternator? It seems a bit left field, but if the starter connection were messing with the alternator, perhaps the alternator could have been messing with other components on the BSD system. Again, I don't have a good enough understanding of the interactions. Might be a crazy idea but it would line up perfectly with the starter replacement being the root cause. Of course to get to the connector, I'd need to take out the intake manifold, so it's not an easy test. Crazy idea or not crazy idea?

 

[AdamJC]

Quick note - I sent an email to Pierburg/Rheinmetall and a Service Engineer from Dormagen, Germany is helping with the problem! I've shared some more details with him so hopefully he'll have some insights. I'm impressed that they responded. Usually companies only deal with their direct Manufacturers or Distributors. Thumbs up for Pierburg!

 

[habbyguy]

Whoa... that's odd. Depending on the actual voltages you're measuring, that is.

It would be potentially normal for the voltage to sag a little if the engine speed was reduced to below idle speed, if the battery isn't fully charged, at least. But if you're seeing the "battery voltage" dropping below 12 volts with the car running, it COULD be causing your other maladies. All those electronics get really fussy when you take away their nice, clean 12-14 volts!

What is the "normal" voltage, and what is it dropping to when the engine stumbles?

 

[AdamJC]

The normal running voltage seems to be about 13.7 volts, and when it drops it drops into the 12's. Not a huge drop, but keep in mind I'm getting my readings from the scan tool that's talking to the DME. I don't know where the original reading comes from. I'd guess from the IBS, but when the IBS is unplugged I still get a voltage reading, so who knows. There seems to be a delay in the reading though so I'm thinking it could actually be dropping below 12 volts, but since the drop is for such a short period it never registers that low because the power comes right back on. While it makes sense that a sudden drop in voltage could cause a whole bunch of other problems, why would the drop not happen when the water pump and IBS are disconnected...

 

[scottalexander]

Nice to hear Pierburg is helping with the problem.

With thousands of people ob BimmerFest.com its a good idea for them to weigh in.

At some point Pierburg will tell us what they believe the problem is likely to be


Let's have some fun and make a few predictions when Pierburg comes back to you. They will say:

a) your problem is very sophisticated and we are working with Steven Hawking's younger brother to diagnose the issue

b) your BMW has coronavirus we are working with the Wuhan team. I hope we can get it fixed while you are still young

c) this issue is cake and my grandmother has been assigned to contact you shortly with the resolution

d) ?

 

[AdamJC]

Haha! Nice

 

[AdamJC]

You are not going to believe this. I think the problem is solved!

As I've been contemplating voltage drops, that nagging theory about bad coils was bouncing around in my head (mentioned in post #42). Just like the starter cable connection theory, I didn't like it because even if it were a bad ignition coil causing all sorts of problems it makes no sense that unplugging the IBS and water pump would stop the problems from happening. The voltage issues would still exist regardless of what was plugged in. Still, it was bugging me, and I figured it was an easier test than getting to the starter connections. While it seemed like a long shot, since I had a spare ignition coil, I replaced each coil one by one, and started the engine, experiencing the rough running each time. On the fourth coil, I noticed the coil I pulled out had a broken ground pin.* Replaced it with the extra coil, started the car and now the car seems to run perfectly even with the water pump and IBS plugged in.* I'll test it again tomorrow when the engine is cold.*

This makes no sense to me.* It's also amazes me that a car can have a bad ignition coil causing all sorts of voltage and engine cut-offs and throw zero codes. If anyone has any insight how unplugging a water pump and IBS from the system can alleviate the engine cut off symptoms, stemming from a bad ground on an ignition coil, I'd love to hear the theory.* I'm glad it appears to be working now.* By the way, here's the link and explanation from the referenced post in case it helps anyone figure this out.

Link
Explanation:
Root cause:
Aftermarket Delphi coils sending voltage spikes back through the "ignition" circuit due to insufficient insulation.
Side effects:
BSD codes, alternator damaged by the coil voltage spikes, causing the alternator to send its own voltage spikes through the charging circuit
Diagnostic path and fix:
1) Replaced alternator after observing it spiking voltage on charging circuit; new alternator does not spike voltage, but BSD codes still present (and related drop to battery voltage when present)
2) So tested other components on BSD line - all good; then tested ignition circuit and observed a separate voltage spike on that circuit coming from the coils (not a misfire in combustion chamber, so no misfire codes). Replaced coils with genuine OEM coils and these voltage spikes disappeared.**

Anyway, thanks again for all the help and suggestions. It's truly appreciated! Hopefully all your insights help many others. Feeling humbled by how much I still have to learn, but in the mean time I'll be driving around

 

[scottalexander]

Wow!

Congratulations on identifying the bad coil. If you go back in your earlier writings you will see you always suspected a coil problem, but didn't run tests.

One of the philosophies many use on this forum is...when one coil goes bad just replace them all because another one is likely to go bad.

The other philosophy is look to the obvious. What is obvious and sitting in front of our noses.

Let's go one step further. You did a lot of proactive maintenance in the beginning. What if you did it in stages and fire-walled the stages. That way after you changed the spark plugs and only the plugs we could have figured out and honed in on just the spark plug replacement process as the culprit?

Your situation was a awesome learning experience.

We still need to figure out the correlation between a bad coil and disconnecting the water pump so the car will start.

Circle back to your new contact at Pierburg with the findings and get their opinion on that one.

 

[twh]

I'm wondering if the ground pin was missing, if it was corroded or somehow otherwise was causing an intermittent short between a couple other pins. That could even have been influenced by engine heat.

 

[AdamJC]

@scottalexander - All very good points. Yes, one project at a time from now on. I did update my contact at Pierburg - no word yet, but my follow up email may have been a bit complicated. It's entirely possible the engineer might not have a complete understanding of the BMW component interactions even if they know all things water pump. Plus there is a language barrier which may make it more laborious to reply in detail. If I get further feedback I'll definitely post it.

@twh - The ground pin was bent up. I'd previously identified a ground connector (the female connection, not the coil) that had pushed back and may have made a bad ground in a second coil. It's likely that at least one of these conditions was a self inflicted wound. I may have used too much force rather than finesse when putting things back together.

It's also possible that two bad ground connections may have been what pushed things over the edge, thereby damaging the alternator, and possibly also the oil sensor, both of which I believe either were faulty or became faulty as a result of the condition. I'd like to have a better understanding, but regardless, I'm the recipient of some good practical lessons as well as a few technical ones. And just to confirm, I tested the car this morning - cold and rainy - works like a charm Thanks again.