Philes’ Forum – Summer 2019


By Vic Lucariello, Sr.

Hello Bimmerphiles! Before we get to the sputtering saga, I need to correct an error I made in my last column, which addressed M3/S14 cooling-system flushing. I transposed Photos 3 and 4, and a vast multitude of you emailed to excoriate me for the error, which I apologize for. Heck, Editor Faber even docked my pay!

For years, Joanne and I had an 86 325e 4-door which we dearly loved. Texas car bought from the original owner. It carried us on several round trips to Colorado, a trip to Boston, and another to South Carolina. All without missing a beat and while returning 30 miles per gallon on the highway. So, when it began “hiccupping” when hitting significant bumps, I was surprised. The hiccup devolved to a “sputtering”, and then to an occasional temporary no- crank situation when hot.

During the symptoms’ devolution, I checked out the electrical system numerous times, doing voltage-drop testing of the power supply and grounds. Due to the intermittent nature of the symptoms, they were never present when I did my testing, and as you might expect, I never found anything remotely problematic. The symptoms, including the hiccup and sputter, seemed electrical in nature, yet the battery and alternator tested good, and my voltage-drop testing never revealed the source of the problem. I had previously encountered batteries that tested good yet caused strange electrical symptoms, so I switched batteries with my M3. While changing batteries, I cleaned the battery posts and terminals, and removed and cleaned the engine-ground- strap connections and the battery-ground-strap connection in the luggage compartment. These connections are the first things to check in electrical troubleshooting. The problem persisted. As the symptoms began to appear more frequently, I even disconnected the alternator and drove the car, but the problem remained. In some cases, a failing alternator can cause strange electrical problems such as I was encountering. By the way, the newer the car model, the more likely this is.

Finally – and luckily – as I was pulling into my Mom’s driveway, the beloved old E30 sputtered, then quit. There seemed to be no electrical power in the car. “Ah-Hah”, I cried! With the car dead it should be easy to find the problem! Alas, by the time I broke out some test meters, which by now I was carrying with me, the car started fine and ran normally. WTF?

It was finally time to break out the BMW ETM, or Electrical Troubleshooting Manual, which has schematics for every electrical circuit on the car. The schematic shows a separate feed from the battery to the engine-control computer [DME in BMW-speak], but all other power other than the starter motor’s travels on a single wire from an underhood junction with the battery cable to the underhood fuse box.


After disconnecting the battery in the luggage compartment, I first checked the fuse-box-power-supply [FBPS] wire’s connection at the underhood junction with the battery cable. The connection seemed clean and tight, but I disconnected it and cleaned it with a fine Scotch-Brite pad. Finding the other end of the FBPS wire is not so easy, so rather than major surgery, I tried the following.

To gain access to the FBPS connection to the fuse box, you would really need to disassemble it, but there is a little trick that sometimes suffices. First, remove relays K3, K4, K7 and K8. The relay identifications are indicated on the fuse-box cover. Doing this is greatly facilitated with a relay-pulling pliers. See Photo #1. An internet search for “Bosch Relay Pliers” will reveal several sources for this handy tool, which you shouldn’t work on BMWs without.

Photo #1 – Relay Pulling Pliers

Once the relays are removed, Photo #2 shows the top end of the FBPS connection with a 4-mm hex bit installed in it.

Photo #2 – Checking The Fuse Box Power Supply

Note that the hex bit is a ¼-inch drive! You don’t want to use anything larger for this. Trust me. You can also use a 4 -mm “Allen Wrench”. I tried both the hex bit and the Allen, and the hex bit is preferable. See if you can tighten the FBPS connection a bit. If not, loosen it slightly and then retighten. Repeat a couple times.

After I tried this on our beloved E30, I was not sure I had accomplished anything, so I connected a couple digital multimeters, one with max-min-record capability, to two wires in the under-dash harness that I felt would be good to monitor when the symptom recurred. One was the power supply to the ignition switch, fed by the FBPS wire, by the way. The other was the ignition switch “RUN” output. I thought this would capture an intermittent ignition-switch problem, which would be consistent with the symptoms.

Well, as you might expect, now that I was poised to capture the problem, it never recurred! So I have to conclude that my manipulation of the FBPS connection was the “Fix.” It’s probably a good idea to check your E30s FBPS connection whether it needs it or not. I know I checked my M3’s!

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at I’m interested in comments, tech tips, repair /maintenance questions, repair horror stories, emissions inspection sagas, product evaluations, etc.

© 2019; V.M. Lucariello, P.E.

Philes Forum – Fall 2016


By Vic Lucariello, Sr.

Hello, bimmerphiles! I am closing the 30th year of Philes’ Forum publication with a few unrelated tech tips.

Most of us know about or have patronized Harbor Freight Tools. While some tool snobs out there might pooh-pooh HF stuff, my opinion is that some of their hand tools provide good value, especially for occasional or DIY use. Hey, a set of inexpensive combination wrenches in the trunk of your Bimmer beats the heck out of no wrenches. However, according to reports on iATN [International Automobile Technicians Network], you should be wary of HF automotive fuses. These fuses, which come in an assortment, look pretty much like fuses from traditional manufacturers such as Bussman and Littelfuse.

In a recent thread, an iATN member reports testing the fuses from one HF 5-30 amp fuse assortment. He reports that they ALL held about 75 [that’s seventy-five, folks, you read it correctly] amps before blowing! Fuses have a temperature-time curve, meaning that the time to failure depends not only on the amount of current flowing through the fuse, but the amount of time the current flows. For example, a 10-amp fuse might endure 13 amps or so for a few minutes before blowing, while the same fuse should blow much more quickly at 20 amps. Regardless, a 5-amp fuse holding 75 amps for any amount of time is pretty scary.

So, while carrying an HF wrench set in your Bimmer may be a good idea, carrying their fuse assortment might not be.

After writing the foregoing I happened to see the following HF ad for a ½- inch pneumatic impact gun:

The ad claims that the HF is more powerful, lighter and quieter than a Snap-on model, at less than 1/3 the price!

Many of you change your own brake pads, and hopefully you don’t use pads from HF [kidding of course]. I’m sure you use OE [Original Equipment – from your BMW dealer] or OE-quality pads from a reputable aftermarket source, but what about that new pad-wear sensor?

I have previously written about the evolution of BMW brake-padwear sensors, so I won’t repeat my tome other than to say that recent Bimmers use sensors that actually predict how many miles remain until the pads need replacing. Older sensors simply illuminated a dash lamp when he pads wore to the replacement point. The old-style sensors could be reused if they hadn’t yet turned the lamp on, but I always replace them. On cars with the newer-style sensor and the Condition Based Service [CBS] feature, it is important that you use an OE or OE-quality new wear sensor when you replace brake pads. I have experienced difficulty, and read others’ reports to this effect, in getting the CBS brake-pad monitor to reset after the new pads and sensor have been installed, and the problem turned out to be an aftermarket pad-wear sensor that the CBS electronics didn’t “like”. An OE sensor fixed things. So, if you are buying brake parts from an aftermarket source, be sure to confirm with them beforehand that the pad-wear sensors they supply will not cause CBS-reset problems. If you inform them of problems afterwards, be prepared to be told that you don’t know how to reset the CBS. [Heck, you will probably be told this anyway.] Personally, I always use OE sensors, regardless of what brake pad I am installing.

Although the following applies to many Bimmer models, some as much as twenty or more years old, this specific account applies to an E46 325i with over 150,000 miles. A fellow had a valvecover- gasket oil leak [Imagine that!] and after replacing the valve-cover gasket he had no more oil leak but he had an illuminated “Check Engine” lamp. OBD II diagnostic trouble codes P0171 and P0174 were stored in the engine control computer [DME in BMW-speak]. WTF!?

These codes set when the DME detects a lean-running condition; the 171 code is for Engine-Cylinder Bank 1 and the 174 code is for Bank 2. Banks on an in-line six? Yes: Bank 1 is cylinders 1-3 and Bank 2 is cylinders 4-6. So the codes suggest that the whole engine is running lean. But how can a valve-cover-gasket replacement cause the engine to run lean?

First of all, whenever you remove a “plastic” valve cover from any BMW engine, especially a six, it is not unlikely that the cover will be warped. Removing the cover and replacing the gasket will NOT correct the warp situation; Indeed, it will probably make the problem worse. Don’t ask me why this is, but it is so. [Remember that on the subject E46, there were no lean-running codes stored prior to the valve-cover-gasket replacement.]

Second, BMW’s engine-crankcase-ventilation [PCV] system tries to maintain a prescribed vacuum on the engine internals. The actual vacuum spec varies from engine-to-engine, but the vacuum one should measure on a warm-idling E46 325i is about 4 inches of water column. If there is an air leak on the valve cover, either due to a bad gasket or that warped valve cover, the PCV will, in trying to maintain the engine internals at the prescribed vacuum, suck a lot of unwanted air into the intake manifold and…..BINGO…..the DME will set lean-running codes.

On the subject E46, the owner lucked out with the valve cover itself insofar as warpage, but when he checked his work, he found a piece of the original gasket had been left on the cylinder head when the valve cover was removed the first time. So the piece of old gasket created the air leak that caused the lean running codes.

That’s all for now, bimmerphiles. See you next time.

Anyone wishing to contribute to Philes’ Forum can contact me at

I’m interested in tech tips, repair / maintenance questions, repair horror stories, emissionsinspection sagas, product evaluations, etc.

© 2016; V.M. Lucariello, P.E.

Related Articles - Philes' Forum