Starter - Motor Failures, Binding/Sticking Ignition: Overview

Group: 12
Engine Electrical

Bulletin Number
12 O3 93 (3824)

Woodcliff Lake, NJ
November 1995
Product Engineering

This Service Information Bulletin supersedes S.I. 12 O3 93 (3824) dated May 1995, which should be removed from your S.I. binder and discarded. This S.I. contains a revised repair procedure for certain E36 vehicles. The black bar and asterisks identifies changes made to this revision.

SUBJECT:
Binding/Sticking Ignition - Starter Motor Failures

MODELS:
E30/E31/E32/E34/E36 (vehicles produced before 6/94)

Situation:

We have received reports of vehicles with failed starters, some with multiple failures. The starter usually does not function after the vehicle is turned off. On E30 and E34 vehicles, symptoms the customer may indicate are loss of sunroof, window and seat heating the last time the vehicle was driven. Vehicles may have a discharged battery as a result of continued starter engagement, and some customers may notice an additional whirring noise from under the hood after starting.

Although few cases have been reported, it is possible this problem can occur on a vehicle equipped with an automatic transmission. In this case, the gear selection switch (neutral safety switch) will cause the starter to disengage as soon as the vehicle is shifted into Drive or Reverse. However, the starter will attempt to re-engage with the running engine when the gear selector is placed in Neutral or Park, causing a loud grinding noise and potential flywheel/starter pinion damage.

Cause:

The steering lock is intermittently jammed or binding in the "start" position. The battery can be drained as the starter continues to run. The "unloader" relays cause the windows and sunroof to be inoperative (E30/E34). The starter incorporates a one-way clutch that allows the engine to spin faster than the starter, so it may be difficult to detect that the starter is remaining engaged. However, prolonged engagement of the starter will overheat the motor windings and may eventually cause the starter to fail.

Correction:

When a vehicle with a failed starter is brought in, or the customer has complaints similar to the above, the starter electrical system (including "unloader" relay circuits) should be checked for proper function. The starter pinion and flywheel teeth should be examined for scoring or other mechanical damage that would indicate misalignment or improper mounting surfaces.

If a check of the starter electrical system and flywheel/pinion does not reveal a problem, the ignition cylinder/lock assembly is causing the prolonged starter engagement. The entire MECHANICAL portion of the steering lock (lock cylinder, steering lock assembly) must be replaced along with the "electrical" ignition switch. The starter must be replaced if damaged.

It is imperative that a questionable ignition lock cylinder be replaced, as repeat occurrences of starter failure are particularly disappointing to customers. To reduce customer inconvenience, it may be helpful to install a precoded ignition lock cylinder temporarily. Although this forces the customer to use two different keys for unlocking and starting, the vehicle can be returned to the customer without excessive delay. When the "correct" coded ignition lock cylinder arrives at the dealership, it can then be installed at a later date convenient to the customer.

Until further notice, any E36 vehicle encountered with the complaint described in this Service Information should be repaired as follows:

A special starter protection relay has been developed that automatically interrupts power to the starter solenoid when a specific engine RPM is reached. This relay is a variation of the Anti-Theft Immobilization Device introduced on E36 vehicles during 1/94 production. The starter protection features were incorporated into the device beginning with 6/94 production. Refer to S.I. 61 01 94 (3955) for specific details on the operation of this device.

* On E36 vehicles produced before 6/94, the starter protection function can be retrofitted. E36 vehicles produced prior to 1/94 require the installation of a relay socket, adapter harness, and starter protection relay. E36 vehicles produced prior to 9/92 and equipped with the M50 engine additionally require the installation of a resistor adapter in series with the black wire of the adapter hamess. Vehicles produced from 1/94 through 6/94 already have the immobilization device installed; these vehicles only require the addition of one wire and a new relay incorporating the starter protection feature.*