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E28 starter cable and ground strap installation.

Learning context

As the weather heats up a bad starter cable can cause starting issues and leave you stranded. Poor-performing electrical cables can cause a rise in resistance that reduces the current through the cable and affect your vehicle’s performance. Ground straps that are worn out or missing can also cause starting and running issues, I experienced this last year in December when the shifter cable was grounded and caused a fire in the cabin of my E28. I am replacing my starter cable and ground straps with the kit available at Bavarian Restoration.

Symptoms of a bad starter cable/Ground straps

  • Intermittent starting issues
  • The car won’t start
  • Engine cranks slowly
  • Dimming or flicking lights
  • ECU malfunction


  1. Starter cable replacement
  2. Body ground replacement
  3. Parts/ tools
    • 13MM socket
    • 10MM socket
    • 17MM socket
    • Drill and drill bit set
    • Cable kit from Bavarian restoration

Starter cable Procedure

  1. Before you start disconnect the positive lead off the battery. Use the 10MM to remove the bolt holding the starter cable from the positive battery terminal
E28 starter cable

2. follow the cable and find the 13MM bolt that secures the cable to the starter. The reason why it is important to disconnect the positive battery terminal before working on the starter cable is because the exciter cable is really close to the starter cable. If you are not careful and your socket makes contact with the exciter cable the starter will engage.

3. After unbolting the 13MM nut unclip the cable from the plastic retaining clip under the intake manifold. I broke the upper tab on this plastic retainer, if I had to do this again I would take a heat gun and heat the clip to prevent it from breaking.

4. Take your new cable and bolt it up to the starter, because of space I bent my tab slightly to better fit on the starter. Remember to clip the new cable back into the tab, it prevents your starter cable from rubbing on anything in the engine bay.

5. The cable was slightly longer than the stock cable to get the appropriate length, I re-routed the cable through the coolant reservoir bracket. Just like that, you changed your starter cable, now let’s get the ground straps changed out.

Groudnstraps Procedure

  1. In the engine bay, there are two ground straps, one is on the passenger side engine mount to the engine bay wall. The second one is on the passenger side of the firewall connected to the last bottom bolt of the valve cover.

2. Use the 13MM to remove the nut holding the ground strap from the engine bay to the engine mount.

13MM nut on ground strap

3. Use the 17MM to remove the nut off of the engine mount, I found it easier to get this done from underneath the vehicle.

4. The new ground strap hole is to small for the engine mount stud, so I use a 3/16th drill bit to widen the hole enough to install.

5. Tighten down the engine mount nut to 25 ft/lb and the firewall nut to 16 ft/lb to secure good contact.

6. Use your 10mm socket to remove the valve cover nut.

7. Becasue of space restrictions I couldn’t get to the phillips screw driver between the firewall and engine head. So I got creative and took a baby preassure plier and a phillips bit.

8. When re-installing the valve cover nut remember to place your washer over the ground cable lead. Tourque the nut to 10Nm, dont want to overtithen and break the stud off.


Replacing ground straps and main power cables is not the most exciting modification to do, but it is needed for a reliable vehicle and that is what I am going for reliability. The stereo static has cleaned up allot after replacing the ground strap on the firewall and the dash board lights are noticisably brighter.

After I completed this job I went to harbor freight to get some heat shrink, and saw this tool which could of helped allot with the firewall phillips screw. It is a locking flex ratchet from Icon, I think its worth the price for those cramped bolts.

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