JIGGS86 1985 735i  163,000mi+

TESTING THE COLD START VALVE

For what it's worth, this procedure for checking the cold start valve is from the Chilton's "Coupes and Sedan's" Repair Manual:

1. Remove the cold start valve from the induction header.
2. Connect the relay terminal (C87) to a positive battery connector.
3. The cold start valve should eject fuel.
4. If not, it should be replaced.

I have not tried this myself, but probably will this weekend. The location of the relay and C87 pinout is shown below. In the Elec Troubleshooting Manual it is referred to as the "Fuel Pump Relay".

Anyone that can add or correct to this please do... email:  jiggs86@roadfly.org

IMPORTANT - IDENTIFYING THE FUEL PUMP RELAY            

fpr_oxy_relays.jpg (20377 bytes)

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FUEL PUMP  AND OXYGEN SENSOR RELAYS ARE OUTSIDE THE POWER DISTRIBUTION BOX

POWER DISTRIBUTION BOX LAYOUT

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FUEL PUMP RELAY IDENTIFIED BY THE RED WIRE

FUEL PUMP RELAY PINOUT

NO START TROUBLE SHOOTING

tlight1.jpg (11813 bytes) AN INVALUABLE TROUBLESHOOTING TOOL, THE TEST LIGHT!
tlight2.jpg (20344 bytes) YOU SHOULD TEST YOUR "TEST LIGHT" BEFORE USING.  

ATTACH ALIGATOR CLIP TO ONE SIDE OF BATTERY TERMINAL (+ OR -), WHEN YOU TOUCH THE TEST LIGHT TO OTHER BATTERY TERMINAL "TEST LIGHT" SHOULD ILLUMINATE!  NOW YOUR READY TO

TROUBLESHOOT ELECTRICAL PROBLEMS!

 

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THE SCHEMATIC SHOWS THAT THE ELECTRICITY FLOWS FROM THE IGNITION SWITCH, THROUGH THE START RELAY, AND DOWN TO THE STARTER.   YOU COULD VERIFY THAT ELECTRICITY IS GETTING TO THE STARTER BY USING THE TEST LIGHT ON TERMINAL #50 ON THE STARTER.   BUT A MUCH EASIER ACCESS POINT (CIRCLED IN RED), IS DIAGNOSTIC CONNECTOR PIN #11.   SEE THE DIAGNOSTIC PIN DIAGRAM BELOW.   (NOTE THIS IS FOR A 1985 735i, BUT COULD BE THE SAME FOR ALL E23 MODELS??)

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SO HERE IS A VERY EASY TEST PROCEDURE TO SEE IF YOUR STARTER RELAY IS WORKING:

1.  CONNECT THE ELECTRICAL TEST LIGHT TO GROUND, OR THE NEGATIVE TERMINAL ON THE BATTERY.
2.  INSERT THE TEST LIGHT POINTER INTO PIN #11 ON THE TEST CONNECTOR.
3. TURN YOUR IGNITION KEY TO THE "START" POSITION.

4. IF THE "TEST LIGHT" ILLUMINATES, THEN THE START RELAY IS WORKING FINE AND ELECTRICITY IS GETTING TO THE STARTER.  I WOULD WANT TO VERIFY THIS BY DOING THE SAME TEST PROCEDURE WITH THE TEST LIGHT ON TERMINAL #50 OF THE STARTER.  YOU THEN SHOULD START TROUBLESHOOTING THE STARTER AND POSSIBLE STARTER GROUND PROBLEMS.

5. IF THE "TEST LIGHT DOES NOT ILLUMINATE, THEN YOU SHOULD  LOCATE THE STARTER RELAY, WHICH IS LOCATED UNDER THE LH DASH ON THE BODY ELECTRICAL BRACKET.   YOU CAN IDENTIFY IT BECAUSE IT WILL HAVE 2-BK (BLACK) WIRES, 1-BR/BK (BROWN/BLACK), 1-BL/YL (BLACK/YELLOW). 
  a. REMOVE THE START RELAY.
  b. CONNECT THE TEST LIGHT ALLIGATORS TO A GOOD GROUND INSIDE THE CAR.
  c. INSERT THE TEST LIGHT INTO PIN #30 OF THE START RELAY SOCKET PLUG.
  d. TURN THE KEY TO "START" POSITION.

IF THE LIGHT DOES NOT ILLUMINATE YOU ARE NOT GETTING POWER FROM THE IGNITION SWITCH.   IF THE LIGHT ILLUMINATES, THEN:

THE RELAY IS BAD, OR WAS NOT GETTING A GOOD CONNECTION.  I WOULD CLEAN THE RELAY CONTACTS WITH TV TUNER CLEANER, OR ELEC-CLEAN.  REINSTALL IT AND SEE IF YOUR STARTER WORKS BEFORE REPLACING THE RELAY.

OR

THE RELAY COIL GND WHICH GOES DOWN THROUGH THE TRANMISSION (FOR SAFETY STARTING) IS BAD.