(Yet another) M42 top end refresh and engine reseal (mid-2021)

[bmwman91]

If you pull the negative terminal connection, the car will die regardless of the state of the battery or alternator. It makes the whole electrical system go open circuit and there is no return path for the ignition, fuel injection, etc.

Chances are that the battery is just totally crapped out. Even with a good alternator, if the internal electrodes are totally eroded and/or the water levels are super low, it won't take a charge. Hopefully it is just a matter of replacing the battery!

[jsnppp]

Ah I misunderstood your ask. I can't check the voltage now b/c I removed the alternator. All I do know is that regardless of the battery voltage at idle, the engine would turn off immediately if I pulled the negative terminal. This tells me the alternator wasn't putting out enough to run the car.

I'll keep at it, once I get the new VR I can test more things assuming it doesn't fix the issue..

Jason

[monty23psk]

I believe 0 volts. I pulled the negative terminal off the battery while idling and the car immediately died. My guess is alternator isn't putting out anything at the moment.

At least thats the theory at the moment.

The car should show something, with both leads on and car is on. Knowing the voltage on the battery (car has to be on and both terminals connected), can tell you if issue is with alternator, VR, or something else.

[jsnppp]

What is the battery reading with the car on at idle?

I believe 0 volts. I pulled the negative terminal off the battery while idling and the car immediately died. My guess is alternator isn't putting out anything at the moment.

At least thats the theory at the moment.

[monty23psk]

What is the battery reading with the car on at idle?

[jsnppp]

We are still ironing out some details. I haven't been maintaining it on a charger and last time we drove it around the neighborhood it died and then wouldn't turn over with the key. Battery was nearly empty! Started it in reverse with a clutch pop (daughter was impressed) and got it home. At the end the tach and speedometer weren't even working! The charger said it had 10v once I plugged it in. Damn.

I haven't noticed that the battery light was not on when I first turned the key. So, clearly it's not been charging. It does need a new battery.

Ran through the usual suspects. Checked B+ for 12 volts (all the time) and D+ for 12volts when key is at position 2. Then pulled the cluster (again) to verify bulb wasn't burnt. Was fine.

So, next step was to pull the voltage regulator. There is a cheap Hella that appears to have some wear. It's an 80amp alternator and doesn't have loose bearings or other noise, so I'm hopeful that it's just voltage regulator. Any other thoughts are welcome. New one ordered.





While alternator out, took the opportunity to change transmission fluid. Used Valvoline ATF but will switch to Redline D4AF when we pull the transmission to redo rear main seal and transmission seals (+ other stuff) later this Spring.

Sharf - not bad. Old oil was relatively clear. When we change it later this year can see what it looks like again.





Cleaned off before replacing:



Filled up. Ran an extension hose up through the engine bay.



More soon! Once the alternator/charging is fixed we can take it out farther and get it inspected.

[jsnppp]

That'll be lifters. What oil are you running? Might be better with a 0w or 10w, if you've got thicker

I put in what I had for dino oil on this first refill. It's thicker than recommended for sure, and it's been a bit colder here. When I change it for the first time (after 100 miles or so) I'll put in 0w or 10x40 (whatever dino oil is recommended). Hesitant to go with full synth in case it leaks!

Jason

[econti]

That'll be lifters. What oil are you running? Might be better with a 0w or 10w, if you've got thicker

[jsnppp]

It actually goes away in seconds, I'm thinking it's just hydraulic lifters...

Spent a few hours today tracing back brake lining light + soldering in the oil inspection bulb (converted to LED). I reflowed all the cluster contacts but it wound up being a flaky connection at the right rear wheel. Wire looked fine on the outside but apparently had a break. Soldering under the car is always fun. :-)

I now have a "pegged temp gauge" issue. Must have been when I reflowed it because it was fine before. Pulled the cluster again and shouldn't be hard to trace.

[jsnppp]

Slight knock when you start it up. Light. Seems to go away after 30sec or so. It's relatively cold out here so maybe it is hydraulics.

I read through a bunch of posts on this topic, mostly it's alarming if it doesn't go away. Note we still haven't really driven it.

I'll capture it on video..

[jsnppp]

Congrats!! It's got to be a good feeling to drive it around a bit. A proper project always has some sort of minor issue that needs addressed after....I'd be nervous if there wasn't.

Totally agree with you. This one has been pretty minor so far. It appears to be eager to go and no major sounds/leaks to take care of. Just working through the cluster (believe I found the issue), reinstalling sunroof and looking into why the brake lining light decided to turn back on. :-)

[mjweimer]

oh, my daughter and I did drive it more today around the neighborhood. We haven't yet romped on it but we will. I noticed some power steering fluid leak on the hose from the reservoir to the rack.

The one hose I didn't replace because it looked good and is $100+. It still may be just oil burning off so I'll keep an eye on it.

~Jason

Congrats!! It's got to be a good feeling to drive it around a bit. A proper project always has some sort of minor issue that needs addressed after....I'd be nervous if there wasn't.

[bmwman91]

Well, if it is starting repeatedly and reliably then I'd say that it's a good indication that you did all of the important stuff properly! The PS hoses are sort of a PITA...the ones from the reservoir do seem to leak chronically. I assume that the rubber dries & cracks a little up at the reservoir nipples. Since those are all zero-pressure lines, it is probably fine to find some generic PS hose of the same ID, some metal union barbs, and to chop off the cracked ends and splice on new ones. That is what appears to be the case with my hoses anyway!

My cluster also has the last LED not lighting up, and even after getting a fully refurbed one. I am not sure if it ever lit up, although I would assume that it is supposed to. Let me know if you figure that one out.

[jsnppp]

oh, my daughter and I did drive it more today around the neighborhood. We haven't yet romped on it but we will. I noticed some power steering fluid leak on the hose from the reservoir to the rack.

The one hose I didn't replace because it looked good and is $100+. It still may be just oil burning off so I'll keep an eye on it.

~Jason

[jsnppp]

Got caught up doing other car repairs today - mostly wasted some time changing fuel injector seals on a 1988 acura integra. I dropped one of the injector filters and b/c of that wasted 2 hours trying to find it in the engine compartment! Ah well. Never found it.

I'll absolutely look into the sssquid chip even if it has a turner in it..

~~~

One thing new - the SI board needs to be pulled again. I don't like that one green LED is out nor that the econometer gauge doesn't work (it only moves when you rev it high). I tried swapping batteries but they didn't work despite being new. Then I read that new batteries without new transistors may cause other issues. So, I put the original batteries back but now have these two problems. Ugh! Bugs me that it was working before I changed the batteries but I thought I'd do the right thing and replace them while it's all out.

I may pull the SI board and reflow all solder connections I can reach, change the green LED and see if anything is burnt visually..

One thing at a time! Patience. At least it moves!