Cheerfully Laboring on Labor Day

We’re using Labor Day as a good day to clean up our front storage room; the room has huge picture windows and the view isn’t exactly inspiring … maybe it was in 1937 when the building was erected.

Right now we’re more concerned about people looking in than us looking out. Although the little town where we are located has an ultra-low crime rate, I don’t want to be the exception, and bins full of who-knows-what might be tempting to someone who really, really needs some money for the next shot of heroin or helping of meth. So I’m doing my bit for fighting drugs by keeping druggies from stealing my stuff; very socially responsible of me!

Here’s the north-facing window. It’s huge, and it gets down to single digits in the winter (yes, Fahrenheit), and the north face is the coldest section, so I put shades up for the neighbors and passers-by to not see industrial-strength insulation (what a nice neighbor I am) and then a huge thick panel of insulation.

So when you order parts from us in December, we won’t have to break icicles off your parts before we box and ship.

Here are some pictures.  Can you guess what flavor of BMW these doors are from? (Hint: it’s NOT a 3-series car; yes, we also manage, and

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3 Series Parts Road Trip

Our trusty 1989 325i made a big circle trip over 10 days:

  • Start at Fallon, NV
  • Highway 95 (mainly) to Las Vegas, NV
  • Highway 15 (mainly) to Orange County, CA
  • Highway 101 (mainly) to Arroyo Grande, CA
  • Highway 1 (mainly) to Monterey, CA
  • Highway 101 (mainly) to San Jose, CA
  • Highway 80 (mainly) to Reno, NV
  • Highway 50 (mainly) to Fallon, NV

Here it is in the parking lot of the Hampton Inn at Arroyo Grande, in foggy evening weather.

E30TRIPThe little car ran perfectly, even though it left Fallon without a cooling fan because a blonde lady who shall remain nameless left a 22mm wrench on the end of the crank nut after doing the valve adjustment, and then started the engine. Oops!!  Saw ree.

In Las Vegas, the blonde did penitence by lying on a concrete slab in 102 degree weather in the heat of the day, gazing up at a dead E30 engine compartment, to remove another cooling fan from the Pick-A-Part junkyard there. Fortunately she’d brought the 32mm wrench along with her on the trip.  It’s in the list of “what every girl should take on a road trip.”

The ironic thing is that Tanya naturally has negligible eye lashes, and she’s tired of trying to turn nothing into something using vast amounts of mascara, so she got some (semi) permanent eye lashes professionally glued on Las Vegas.  Problem was that after the treatment she wasn’t allowed to get them wet, and she’d laid on her back in the desert dust in the junkyard right before rushing to the eyelash gluing session. So, for next 48 hours, she was a very dusty blonde.

The rest of the trip was almost normal, with the exception of having to rescue a dead black 6-series BMW in the middle of the night on a deserted off-ramp of highway 101.

Never boring, life at 3 Series Parts. 🙂

The Design of the Fuse Box: Yet Another Reason to love the E30 BMW

I used to own a 1974 Opel Manta, and it had some wiring gremlins.  I was already a software engineer back then, and sometimes when things are enough of a mess, it’s time to rewrite the source code.  So, for similar reasons, I decided the Opel could use some basic rewiring.

I never completed the project, but in the course of it, I came up with some fresh ideas of how a car’s electrical wiring could be really great.

When I was nineteen, a friend of mine offered me $100 to rewire his entire car, every wire in the vehicle to be replaced with a fresh wiring harness.  This was on a 1972 South African spec Renault 16 TS. I agreed, and spent the next three days regretting it.  So, I have a pretty in-depth opinion about cars’ electrical wiring.

Owning a few Volvos, and dealing with a friend’s Pontiac, helped me form the opinion that many cars have the fuse box located in a place that necessitates kneeling by the side of an open front door and peering at dark recesses. The Volvo fuse box is fairly near the door opening, so it’s not as bad. On the Pontiac, I learned some new contortionist’s skills in order to reach the fuses.

On my 1992 Ford E150 van, the fuse box is named “Power Distribution Box.” It’s in the engine compartment. Working on it is a lot easier than lying face-up below the dashboard, but it’s still sort of awkward to reach down and work with the fuses and relays.

What would be a really great design, I ended up concluding, would be a fuse box that contained the fuses and relays in an easy-to-get-to place where I didn’t have to lie down or stoop or kneel.  Perhaps they might even be in a little box with a cool clear plastic lid.  Wouldn’t that be SO cool?


That is precisely what BMW did with the E30.  When I first saw this design on an E30 car, it was almost like dreaming about some futuristic contraption and then seeing one in real life.  I was delighted.  Since then, I have been grateful for this design many times, including as recently as tonight.  Working on the fuse box of an E30 is, comparatively, a delight.

Kudos to Claus Luthe, the late designer of the E30.

Chasing a Short Circuit Downstream of the Fuse Box on an E30 BMW 318i

The gauges in the instrument panel of my 1984 BMW 318i are, with the exception of the speedometer, all dead. I checked fuse #10 in the fuse box, and yep, this mighty 30 amp fuse was blown. That would explain the dead gauges.  I replaced the fuse and as soon as I turned the ignition key to “on” the fuse blew again.

So, the issue is a short-circuit downstream of the fuse.

I looked at the documentation, and it shows how the wiring from the fuse goes along three separate wires, two of them being green-and-white and attached to the instrument panel, and the third wire going … well, I haven’t as yet been able to figure that out.

This makes the instrument panel the prime suspect. I removed it, installed a fresh fuse, turned on the ignition key … and the fuse blew again.

So, now I can conclude that the issue is a short-circuit between the fuse and the third wire, wherever that goes, or in the wiring or connectors for the two green-and-white wires.  I was hoping for an easy fix, but … no such luck.

The bottom of the fuse box has always seemed intimidating to me, but tonight I dealt with it.  I disconnected the battery, and I took off the clear fuse box lid, and saw a Philips screw. I removed it.  I tried to lift the top of the fuse box, but it didn’t budge.  I removed the two relays close to the firewall, and found a second Philips screw, sort of diagonally opposite the first one. I removed it, and then I was able to lift the top part of the fuse box off. Yay!

Next to the inboard row of fuses, including the #10 fuse in which I’m so interested, was a set of four black plastic catches. I slipped these, and it loosened a piece of plastic whose purpose perplexed me, and aside from that it didn’t seem to make a difference.

So, I peered underneath and saw a couple of green-and-white wires, wound together and coming out of the area where fuse #10 would be.  Interestingly, although both wires were green-and-white, they had different styles so it was possible to tell them apart.  Clever, these BMW engineers.

I traced the wiring and saw the two green-and-white wires vanish into a massive wiring harness that exited the base of the fuse box.  I loosened an 8mm bolt at the front of the fuse box base, and was able to lift the base up enough to see the wiring harness go through a hole in the firewall.  I opened the driver door and peered underneath the dashboard area, and I could see the area where the wiring harness entered the passenger compartment.  I could even make out the green-and-white wires.  So, now I get to trace these, inside the car.

IMAG9289I put the fuse box components back the way they were, except that the black plastic piece didn’t fit as snugly as before. I hope that won’t cause problems.   I reconnected the battery, then started the car to make sure it would start and run. It did.  Yay!


Using a smoke pump to chase an intake manifold vacuum leak

My 1984 BMW 318i has a too-high idle.  Before I suspect the idle control valve, I’m eliminating vacuum leaks.

I read about a nifty technique of pumping smoke into the intake manifold and then observing where it leaks out, and that would identify the vacuum leak.

Professional mechanic’s tool companies like Snap-On make machines that generate and pump smoke but as I understand the pricing, the cheapest one starts at $750 which is about $735 more than I can afford.  So, I made my own.

I hasten to say that it doesn’t work yet, but I’m hopeful.  At least half of the functionality (generating smoke) is working VERY well.  The prerequisites (not asphyxiating anyone or causing a fire) are also being met.

I opted for the technique of dripping ATF onto a hot soldering iron. The business end of the soldering iron is held inside a plastic file folder carrying case that I got at Wal-Mart for $8.  The cool part (literally) and the cord are outside the case. I made a hole in the side of the case about 2/3 of the way up. A set of stacked rubber bands holds the soldering iron loosely in position.

My plan had been to rest the tip of the iron in a can of ATF but the iron doesn’t then get hot enough to make smoke.  So, I put an empty tuna can below the tip of the soldering iron and I made a hole in the lid right about the tip of the soldering iron. Into this hole I placed a small funnel into which the ATF goes.  I plugged the funnel with a piece of paper towel to slow the flow to a slow drip.  That worked well.  So, the pool of ATF in the funnel oozes, drop by drop, past the paper obstruction and drips onto the tip of the hot soldering iron, causing smoke.  Any missed ATF  droplets get collected in the can below.

I removed the handle of the case since it had sizable gaps around it, and I plugged the holes and the gaps around the funnel with room-temperature-vulcanizing glue (aquarium cement, basically). I missed a small hole around the funnel, and I inadvertently found it by seeing a clear smoke trail exiting from the leak.  I hadn’t intended to build a leaky smoke box, but the fact that it found its own leak was pretty cool.

In case the ATF might spill and make a mess, I put a cardboard egg carton at the bottom of the case. That way the entire contraption is elevated so if there’s a mess, it’ll be harmless, below the main components.

I tested this aspect, and the smoke-generating process works great.  Fires caused: zero.  Body count: zero.  Yay!

Also at Wal-Mart, I bought an aquarium pump for $8.  I made slots in the lid for the power cord to the pump, and for the air hose that is supposed to guide the smoke to the car.  But, even with the pump buzzing, no smoke exited the hose, though the smoke was otherwise perfectly happy oozing out of even the smallest orifice in the case.

In case it’d make a difference, I removed the intake filter from the pump, and repositioned it so as to be higher in the case, since the smoke is hot and rises to the top.  Still, no smoke exited the hose.

So, I need a better pump.  I plan to go buy an electrical bicycle pump, next.  My fear is that I might over-pressurize the intake manifold and blow out some seals and actually create the problem I’m trying to prevent.

Wow, that sounds like it has all the makings of a government program.



The M10 engine

The M10 is generally considered lame by E30 folks, but it was the engine that brought BMW back from the brink, in the 60s, and has powered the classic 2002 and E21 models.

With a turbo, it produces vast amounts of power, and that’s what powered some VERY fast BMW race cars in the 1970s and 1980s.

there’s no timing belt that can break like in the M20. There’s a nice, long-lasting, chain.

I used to own an M10-powered E21 but that was with lots of smog crap on it, and K-Jetronic.  The E30 variant has L-Jetronic, which is to me a lot less scary.

Re-Installing Rear Seats in an E30

I recently removed the rear seat on my E30 for reasons I’m too embarrassed to explain here.

Months later, today, I put the seats back.  There are some subtleties. For the seat back, I had to remember to move the seat belts so that they’re not trapped underneath the seat back.

At the extreme outside bottom of the seat back (the vertical part) there is a steel band that protrudes downwards, with a bolt hole in it.  There is a corresponding hole in the sheet metal of the car, and the vinyl of the side paneling.  It was hard for me to align the holes. I used a small screwdriver to explore where the holes are, and to help move things around until the holes aligned well enough for me to shove the 10mm sheet metal bolt into place and snug it up.

Before I put the seat bottom in, I got the felt cover in place over the sheet metal. I then snapped the seat belt anchors into their slots at the bottom of the seat back. Then, I moved the seat bottom into position. There are two tabs onto which a spring-loaded section snaps into position. The trick is to push the seat back and down, while grabbing it close to the location where the tabs are.

I just compared my 2-door 1984 BMW 318i to my 4-door 1985 BMW 325, and they seem identical as to how the rear seat re-installation works.

My Rolling Parts Test Bench, a.k.a. My BMW 325i

Last week, I struggled trying to get my 1989 E30 BMW 325i to start. It didn’t have spark. Could it be a bad ignition coil? My tech analyzed the coil using the numbers in the best source I know: the BMW manual published by Bentley (no relation to the car company of the same name). Sure enough, the resistance for the ignition coil wasn’t ideal. But, it wasn’t bad either. So, I wasn’t sure.

Fortunately, I have five (yes, that’s a 5) other semi-dead, mostly-complete E30s around here. I figured that at least one of them should have a healthy ignition coil. So, my tech went around, measuring the coils’ resistance. None was to spec, yet they weren’t horribly bad either.

Puzzled, I swapped one ignition coil after another into my non-starting E30. The car still wouldn’t start. Logically this proved approximately nothing.

Finally, I discovered the fault to have been a loose wire at the battery … the small positive wire was loose, and so the main relay wasn’t getting power. Once I fixed that, the car started.

But, it would have saved me some time had I known that my stash of ignition coils was good.


So, now that my E30 is starting, running, driving etc. I’m using it to test used parts. For example, I have swapped in another E30 325i ECU and I have tested that. For a test like this, I try to go beyond the obvious, so that the car doesn’t just start and idle. I drive it at normal speeds, at wide open throttle and so on … cold engine, warm engine … After several hours of driving on the alternate ECU, I concluded it was good and I took it out (one cable, four screws) again. Now it’s in my parts inventory as a known good item. I’m SURE it’s good.

Why stop there? I didn’t. 🙂

Today, I also swapped in one of the ignition coils whose resistance values was not perfect. I drove the car with the engine at 5500 rpm, accelerating, and the coil kept up just fine. So, I’m categorizing this ignition coil as one more good part. I’m SURE it’s good.

Next, the instrument cluster. I removed the one that used to be in the car because it had issues anyway, and I put in another one. The replacement is working very nicely. But, I don’t want to put back all the trim, just yet. Instead I plan to also test the half-dozen or so other instrument clusters that I have, that are currently “condition unknown.”

Ever since I started I’ve always wanted to have this sort of thing — a car that’s a rolling parts test bench.

And now, finally, I do. I’m happy.

BMW E30 318i Fuel Injection Basics

These notes helped me cure a no-start condition on my 1984 BMW 318i.

The E30 318i Fuel Injection is Bosch L-Jetronic and is fundamentally the same as the fuel injection aspects of the Motronic used on the 325, 325e, 325i as well as the larger-engined 528e, 533i, 535i, 633CSi, 635CSi, 733i, 735i and so on.

However, there are some important subtleties, including the role of the fuel pump relay. On the 318i it plays an unusually central role. When the relay is suspect, I make sure it has positive feed. Then, I hot-wire the positive to one of the terminals to provide positive voltage to the fuel pump, and to another terminal to provide positive voltage to the fuel injectors. The relay has two other terminals too, not relevant for when I hot-wire it. In normal life, these provide the essential input that make the relay work.


The L-Jetronic computer a.k.a. electronic control unit (ECU) is above the glove box.  Its cable looks like the following picture, with pin “1” near the incoming cable:

E30318IBWhen I troubleshoot a no-start situation, I ignore subtleties like the ECU input signals as to barometric pressure, the coolant temperature, and whether the air conditioning is on.

I focus on:

Pin 1: does it provide positive voltage when ignition is on, and does it flash when the engine turns over, in synch with engine speed?

Pin 2: Throttle position switch positive for wide open throttle

Pin 3: Throttle position switch positive for closed throttle

Pin 4: Starter positive

Pin 5: Ground a.k.a. negative

Pin 9: Positive from fuel pump relay

Pin 12: Ground provided for fuel injectors … the main output function of the ECU.

Pin 13: Ground a.k.a. negative

Each of these can be easily tested at the cable, to see if they behave as they should: step on the accelerator pedal all the way to see if you have positive voltage at pin 3, let off and see if you have positive voltage at pin 2, and so on.

I don’t take ground connections for granted. My car had a bad ground connection. The ground connection by the fuel rail plays a key role in this.

The nice thing is that you don’t have to worry about subtleties like how many Volts are involved. The system is really simple as such. When something is supposed to be positive, you either have 12V or you don’t.

Using these basic principles, I was able to get my 1984 BMW 318i to basically fire on start-up. Many other hurdles remain, but this is still a huge milestone.

Meanwhile, I learned that the fuel pump relay for the BMW 318i (with the M10 engine) is a 7-prong relay, and that the 5-prong relays for the M20-engined E30 car won’t work.  So, I ordered a new part from Pelican Parts for $31  and we’ll see what happens.

As to the wiring for the fuel pump relay, it accepts input from the starter when energized (black and yellow wire, code 50) and the ignition coil ground (black wire, code 1).  When the starter is energized or the engine is running, the fuel relay considers that its “green light” to energize. This means that it connects the “always positive” feed (red wire, code 30) to the positive of the fuel injectors (red-and-white, code 87) and the positive of the fuel pump (red-and-white, code 87b). There is also a ground connection (brown, code 31) and a positive feed when the ignition is on (green, code 15).

The basic idea is to prevent the situation where the car has been in an accident, with the key on and the driver unconscious while there’s an engine fire, and the fuel system is literally adding fuel to the fire.  So, unless the engine is turning or the starter is engaged, the fuel pump is shut down.  That’s the logic behind all this, as I understand it.  The internal circuitry of the fuel pump relay is electronic, so we’re way beyond the simplicity of a typical relay.


Looking at Actual Parts, Carefully

I recall my surprise at analyzing some 3-series E30 glove boxes, and discovering that the glove boxes for cars with the later-than-Motronic-1.0 computer had a shallow notch at the inner front corner, so that the thicker fuel injection cable (three rows of pins vs. the earlier two) doesn’t chafe. It’s a very logical engineering change, and not surprising. The glove box with the notch even has a different part number.

What made this surprising is that the official BMW parts list mentions only one variation. So, by analyzing the parts, physically, carefully, in person, I found out more than if I’d just read about things online.

For a while, I tried to figure out what made some cars have the earlier-style glove box vs. not. The change seemed to center around 1987 but I couldn’t put my finger on it until I realized that cars with the older version of Motronic computer had the older version of glove box, and 1987 was the year when things changed a lot as such — but the 1987 325i cars had the newer-version computer whereas the 1987 eta-engined cars still had the older-version computer.

E30 Glove Compartments Showing the Design DifferenceThis experience really inspired me to go look in person at what’s actually going on. It reminds me of when I worked at an automobile assembly plant (not for BMWs, sadly). The production control folks had recently managed a change by which cars of a particular model would be fitted with chrome tips on their exhausts. The parts were ordered, brought to the production line, and the assembly instructions were changed to tell workers to put the chrome tips on. But, at the end of it all, my job included being the reality-check person, to go see if in fact all of this planning had actually resulted in chromed-tip exhausts on cars exiting the assembly line. For me, there’s nothing as solid and reassuring as seeing something first-hand.

So, today’s project involved Mass Air Flow Meters on the M30 engine. I own a 1980 BMW 633 CSi, a 1992 BMW 735i, and several models in between, including a 1984 BMW 633 CSi and a 1984 BMW 733i. My tech and I inspected the mass air flow meters on all of these cars, and checked the part numbers. Of course, it’s possible that some of these parts were not originally on the car, but I’ve personally driven each of these cars so I know that the part at least works on that car.

Although the 1992 car has a pretty plastic cover on top of the mass air flow meter, when the cover is removed, the part is the same as on all the other models we analyzed. And so, now we have a good handle on mass air flow meters for the M30 engine.

There are still a million things we DON’T know for certain, but it’s nice to have a fairly good handle on at least this tiny part of the puzzle.

That’s the sort of confidence and certainty that we enjoy.