BMW and Audi Experiences

Home      BMW 528e (E28)      Maintenance Items
Print this pageAdd to Favorite

Maintenance Items

 
I highly recommend using the Bentley manual for most repairs.  It can be ordered from Robert Bentley Publishers.  You should also consider getting a copy of the "BMW Enthusiast's Companion," also published by Bentley.  This is a collection of articles and technical correspondence from past issues of the Roundel, BMW CCA's magazine.
 
 
 
 
ECU Chip Replacement.
I installed a new DME chip from Bavarian Autosport into the Electronic Control Unit (ECU).  Installation was straight forward -- be careful when prying open the unit to remember which screws go where.  I had originally decided on a Dynan chip, which BavAuto was a dealer for, but they apparently went their different ways just before I called.  I went with the BavAuto version, as its specs were virtually identical to the Dynan.  This was before Jim Conforti had developed his highly-acclaimed chip for the E28.
Remote Keyless Entry.   I installed a remote keyless entry system from AutoLoc- their model 3750. This is fairly easy to install, although the directions leave something to be desired.  It said to trace wires from the driver's door, to gain access to leads that tie into the central locking system.  But I decided to do this in the trunk instead.  I spliced into the wires for the trunk lock mechanism, and mounted the  electronics module next to the AM/FM antenna.
 
Electric Antenna Repair. 
The stock electric antenna is a Hirschmann model Auta 6000EL.  This has a reputation for being a robust design that can be rebuilt.  See the Antenna World web site for information on this antenna - look in the technical information page under AM/FM antennas for information on Mercedes Benz.
 
Idle Surging. 
This was caused by an inoperative Idle Control Valve.  When the valve doesn't work, the engine surges to about 2500 RPM, then dies back to 600, then surges again, in cycles lasting about 5 seconds.  The car will run, but when you come to a stop at a red light the guy in the car next to you will think you're a real jerk for constantly revving your engine!  In my case the fault was due to a broken electrical connection at the valve -- I simply re-soldered the wires and it works again.  I also cleaned the valve out, using WD40.  Over time the valve can get sticky with deposits -- cleaning it with WD40 allows the valve to move much more freely.   If this doesn't solve the problem, you can check for proper operation of the valve by applying 12 volts to the two leads -- the valve plunger should close with a definite snap.  The resistance between the two leads should be about 10 ohms (with electrical connector unplugged).  Please note - my car uses a two-lead valve; some others have three leads.  Check the Bentley manual!
 
Brake Bleeding. 
A popular topic in various FAQs, so I won't go into detail here, except to say that I found a cheap way to do one-man bleeding without fancy pumps or other gadgets.  I wedge a 2x4 board that's about 18 inches long between the brake pedal and the front of the driver's seat, and then use the power seat to compress and hold the pedal.  This allows me to then go to the bleeder screw, bleed the brake line, close the screw, and then go back to the driver's seat and release the brake pedal by moving the seat rearward.  I wait a few seconds, then repeat -- moving the seat forward to compress the brake pedal again, etc.  The FAQs are listed in the links section of this web site.
 
Bad Fuel Pump Relay. 
Symptoms were (1) intermittent stalling of the engine, especially when warm, and (2) sometimes hard to start, when warm.   I changed out the fuel pump fuse, and fuel filter (which hadn't been done in several years).  That seemed to help, but in fact didn't -- I ended up getting stranded one Saturday morning at the garden supplies store.  Hello AAA!  Turned out to be a faulty relay for the fuel pump.  Apparently the contacts got weak with age, and when heated would result in an intermittent contact.  Replaced the relay, and no problems since.
 
Replaced Fuel-Level Sender.  
The low fuel level warning light stopped working,  I diagnosed the problem as a bad sender in the fuel tank - see the fuel-level sender page for information on this. The sender is pretty easy to replace, as the sender and fuel pump are accessible through the trunk.  I installed a new sender from Bavarian Autosport.  This fixed the low fuel level warning light problem, but then I noticed that the fuel gauge and OBC "Range" function were no longer as accurate as they used to be - they consistently read low (they think there's less gas in the tank than there actually is).   See the next paragraph...
 
Inaccurate Fuel Gauge and "Range" Function on the OBC.  
The OBC " Range " function can be calibrated by adjusting a tiny screw that's located behind a plastic plug on the face of the OBC.  See the OBC page for instructions.  However, there doesn't appear to be any way to adjust the fuel gauge.  Oh well.

Bad Connections in the Instrument Cluster.
 
I've had two problems with the instrument cluster, both caused by bad solder connections.  The first was a bad ground, evidenced by funny behavior whenever the turn signals were operated: both left and right indicators would flash, and the speedometer, fuel gauge and tachometer would all waggle in time to the turn signal.  This was caused by a broken trace in the main printed circuit board of the instrument cluster - I fixed this by soldering a wire around the break.  The second problem was that the odometer stopped working along with the MPG gauge and the RANGE and AVG MPG functions of the OBC - basically anything having to do with knoowing how far you've traveled.  Yet the speedometer worked fine.  Turned out to be a poor solder joint for a connector on the rear of the speedometer assembly.
 
Stop that Annoying Ticking! 
For years I lived with a ticking sound that emanated from the area below the dash board by the driver's right knee.   This ticking would speed up or slow down with the speed of the car.  If the car had a mechanical speedometer cable, I would have bet it needed some grease.  But the speedo is fully electronic, so what's the cause? Turns out there's a mechanical device that keeps track of elapsed mileage to remind you when it's time to replace the oxygen sensor.  BMW recommends replacing the oxygen sensor every 60K miles, and they remind you of this by having this device control a light in the check instrument panel.   When you reach the 60K mark this device sends out a pulse that causes a fuse on the rear of the instrument panel to open, which in turn causes the light to come on.  To reset the light, you have to replace the fuse and push reset button on the mechanical device in question, so that it can start counting off the next 60K miles.  Apparently there are gears in this device that can get worn or out of line, causing the ticking sound.  To stop the ticking, you can try to repair the gear, but it's easier to simply disconnect the device.  Simply pull the plug from the front of it, and problem solved.  Just be sure to keep track of your mileage so you know when to replace the oxygen sensor.
 
Cosmetic Improvements. 
These are all very inexpensive, and easy to do. 
  • Roundel Labels for the Hub Caps.  Really dresses up the appearance compared to the yellowing labels that they replaced.  Cost about $4 each from your local dealer .  Simply scrape the old one off and stick the new one on.  Takes less than 5 minutes per hub cap.
  • Roundels for the Trunk and Hood.  Mine had lost all their white paint, so the propeller was silver against a blue sky.  About $8 each; simply pry the old one up (it's held in place by two plastic posts that press fit into rubber grommets).   Be careful not to mar the paint!  Another 5 minute job.
  •  Chrome Strips for the Windshield and Rear Window.  These are chromed plastic parts that tends to grow cloudy over time.  I cheated on this one -- bought the replacement strips (about $20), but then had the dealer install them when I was in for a service.  I've heard that it's easy to do, but it takes some time and it can't be done on a cold day.  There's some more information on my BMW Digest page.
  • Illuminated Window Switches.  The '85 - '87 E28s have window switches that are not illuminated.  This makes it a little difficult to find them when driving at night, and sort of leaves a big visual "black hole" to either side of the gear shift.  I replaced the four window switches, and also the switch that controls the sunroof (it's the same part), with illuminated switches for the '88 model year car.  I decided not to bother with the switches on the rear doors, but I could have done those too.  Go to your parts dealer and ask for replacement switches from the '88 E28.  You'll see that the new switch has an extra plastic tab sticking out the back that won't let you plug it into the connector as is -- just rip the tab off with pliers, and the new switch will plug right into the existing connector.  An easy job, and a nice improvement.
  • Window Seals. I replaced the rubber window gaskets for the two front doors (ordered from my local dealer at $36 each, including BMW CCA discount).  The old gaskets had grown brittle, and parts are crumbling away, which resulted in a lot of wind noise.  The installation of the new gaskets took about 2 hours for the first door and 30 minutes for the second (there's quite a learning curve in removing and re-installing the windows).  I used the Bentley manual for instructions on getting inside the door to remove the glass.
  • New Floor Mats, from Rocky Mountain Motorworks.
  • New Shifter Boot, from Bavarian AutoSports, and shift knob from my local dealer. The old boot had become faded and brittle.  The new one is a tad over-sized, but it works well.  I used a hot glue gun to tack it to the plastic frame that is supposed to retain the boot in the shifter console.  The shift knob is an el-cheapo, generic BMW part.