MechExp6 months ago

Twin Cam engines – The twin cam 4cyl., 6cyl. and V8 engines use combinations of crankshaft and camshaft position sensors. For these applications, it’s best to refer to the applicable Bentley repair manual for mounting position and test parameters. Additionally, these applications will typically generate fault codes that can be accessed by using one of the fault code readers available through Bavarian Autosport.

Mary5 months ago

NO – Determine if there is constant 12-volts at terminal # 30, in the relay socket. If not, trace the circuit for the wire at terminal #30. This should be a constant 12-volts regardless of key position. If you do have 12-volts at terminal #30, determine if there is 12-volts at terminal #86, in the relay socket, when the key is in RUN and START.

Gary19964 months ago

In order to perform these tests you’ll need a few basic diagnostic tools:

Porker4 months ago

YES, 12-volts – The coil may be faulty, the ECU may be faulty or there may be a wiring problem between the negative wire from the coil and the ECU. Follow the ECU harness plug input/output testing as outlined in the appropriate Bentley repair manual (centering on the negative coil wire). There is likely a wiring problem or the ECU may be faulty. If the harness plug testing is OK, you may wish to replace the coil as a first step. If this does not cure the problem, the ECU may be faulty.

Fireboy4 months ago

-No transmission range display in the instrument cluster. -Charge indicator lamp can flicker or it is permanently on. -Fault code 11 the oil level switch is stored in the instrument cluster (E46) -Fuse 15 (E39) or fuse 30 (E46) is blown.

Pete_W4 months ago

Spark OK and Injector signal OK – go to step 11

Pete_W4 months ago

Please see the blog link below for our answer to your question:

petHead4 months ago

Click here to receive our award-winning catalog for free...

R2_Amazeballs4 months ago

Yes, the fuel pump relay may be at fault. The relay sends power to the fuse, then on to the pump. Have you checked for spark and/or injector pulse? What year is your 525i?

Fionas_Boy4 months ago

YES, 12-volts – You likely have a faulty fuel pump. Apply 12-volts directly to the pump to verify that it does not run.

Matchmaker14 months ago

5: Check for voltage at the starter solenoid “turn-on” wire. This will be a small gauge wire that is typically connected to the starter solenoid via a spade type push-on terminal. On BMWs through the mid to late ‘90s, this wire is typically black and yellow. On later models the color is typically black. Remove the wire from the terminal and check for 12-volts between the wire and ground, when the ignition key is turned to the START position.

Col Minessota4 months ago

-Use of the OBC code could occasionally cause the loss of K-Bus communications between the IKE and General Module. (The OBC code is the security code added in to the board computer or MID by the vehicle owner when exiting the vehicle and re-entering the vehicle.) -An error in Instrument Clusters with software lower than SW11.0.

Fionas_Boy4 months ago

NO, 12-volts – You may have a faulty ignition switch, start relay (automatic transmission only), neutral safety switch (automatic transmission only) or a wiring problem in the circuitry between the switch and the coil input wire. Use the wiring diagrams in the applicable Bentley repair manual for further circuitry testing.

Bri19874 months ago

NOTE: On multi-coil models, test for coil input using the wiring diagrams in the applicable Bentley repair manual.

Watergirl4 months ago

-Some functions on the instrument cluster with integrated IKE are inoperative or locked up. - When the power is turned off the instrument cluster may not fully power down which can lead to a dead battery. If the transmission range signal is lost a no start situation will occur.

Bri19874 months ago

Categories → 1 Series Coupe - E82, 1600 / 2002 – E10, 3 Series 84-91 - E30, 3 Series 99-05 - E46, 5 Series 77-81 - E12, 5 Series 82-88 - E28, 5 Series 89-95 - E34, 6 Series 77-89 - E24, 7 Series 79-87 - E23, 7 Series 88-94 - E32, 7 Series 95-01 - E38, 8 Series 89-99 - E31, Bavaria Sedan - E3, CS Coupe - E9, Tech Tips, X3 04-10 - E83, X5 99-06 - E53, Z3 Roadster 96-03 - E36/7, Z4 Roadster 02-08 - E85

Corrie19994 months ago

10: If you do hear a “click” at the starter, when the key is turned to START, this means that the circuit from the ignition switch to the starter solenoid is OK. The “clicking” is indicating that the solenoid is, at least, attempting to energize the starter. Either the solenoid or starter is faulty or there is not enough battery power getting to the main starter motor input terminal. We will now test the solenoid, the starter motor and the battery power to the motor.

Porker4 months ago

I have problem with no start engine in my 323i. The car is cranking, but I check there is no spark. I have BMW scan tool and fault reader, it didn’t find any fault code. Is is possible that crank position sensor is the problem even there is no fault code in the fault reader.

Porker4 months ago

8b: Using the wiring diagrams, determine where the ECU main input power is originating. Test for 12-volts at the origination point for the ECU main input power. On BMWs up through the mid-‘90s there is a main ECU power relay. The applicable Bentley repair manual will detail the location of the relay. Test the output side of the relay socket (the wire that feeds the ECU main power input) for 12-volts when the key is in RUN and START, typically terminal # 87 or 87a.

MDG Ltd4 months ago

NO, fuel pump is not running – go to step 12

petHead4 months ago

SAFETY NOTE: If the fuel pump is operating, there will be up to 75psi of fuel pressure in the system. Assure that there are no open flames or potential ignition sources in the work area. Wear safety glasses and wrap fuel hose connection with a large rag, to catch the pressurized fuel.

Pete_W4 months ago

MY CAR WILL NOT START ,I HAVE BMW 525I AND I HAVE NO POWER TO THE FUEL PUMP FUSE AT ALL , AND THE FUSE IS NOT BLOWN COULD THIS BE THE FUEL PUMP RELAY

Watergirl4 months ago

15: On single coil models, test for 12-volts at the coil positive input wire (typically green, see Bentley manual for specific models) when the key is in both the RUN and START positions.

Bri19874 months ago

2: Do you hear a “click” at the starter, when the key is turned to the START position?

Watergirl4 months ago

A Of course, not knowing the history of the vehicle’s service, it certainly may be time for a general tune-up. Have you tested or replaced the engine temperature sensor (in thermostat housing, with blue connector plug)? Have you done any spark and fuel testing, when it won’t start? This can give us a better idea of what may be going on. See the document below, outlining the tests to perform when in a no-start situation;

Pete_W4 months ago

7: Test for ignition spark and fuel injector pulse signal.

Col Minessota4 months ago

YES, fuel pump is running – Remove the spark plugs and verify that they are clean and dry. Re-install and test to see if the engine will start on starting fluid. If so, perform fuel delivery and pressure tests as outlined in the applicable Bentley repair manual. You may have a faulty fuel pressure regulator.

MDG Ltd4 months ago

1: Does the starter crank, and turn the engine over? If the starter is cranking but the engine is not turning over (rotating), you likely have a faulty starter motor or solenoid and the starter/solenoid assembly likely needs to be replaced.

Fionas_Boy4 months ago

BMW M3 starter solenoid fault

Click here to get the scoop on money-saving deals and more...

Gary19964 months ago

Tags → Diagnostics, E21, E23, E28, E30, E31, E32, E34, E36, E36/7, E38, E39, E46, E53, E82, E83, E84, E85, Engine, no start, Performance, X3, X5, Z3, Z4

Mary4 months ago

Can't find the answer on our blog? Ask Otto... call 800.535.2002.

Bri19874 months ago

What year is your 323i? Have you checked for the injector operation (pulse)? If the fuel pump running (is there pressure in the inlet fuel line)?

Col Minessota4 months ago

3: Check battery condition. Do the headlights come on, nice and bright, blower motor works at full speed, horn honks nice and loud? If you have a digital voltmeter, check battery voltage. The voltage should be at least 12.6 volts.

Col Minessota4 months ago

At this point, you need to get the basic diagnostic info. as laid out in the original post.

FordOwner4 months ago

My 87 528e starts fine in the winter and below 50 degrees, but any warmer than that, it has a “no spark” condition. I have changed the motronic, and the sensors in the bell housing, also the coil, coolant sensor, rotor, and cap. If it gets to where it does start, after it warms up for about 15 or 20 min., it will just shut itself down. I can’t seem to figure this out. thanks, kevin

Matchmaker14 months ago

We have lots of helpful videos posted on this blog - plus some fun ones, too! See the full list...

Mary4 months ago

Q I have a 1989 BMW 325i convertible that is giving me problems starting at times. This has been an ongoing problem for about a year. I initially ran the fault codes and on your recommendation replaced the “Throttle Position Switch”. This problem is still occurring but is intermittent. When this problem occurs, the car turns over with plenty of power but takes several attempts before it starts. Is a tune up in order?

FordOwner4 months ago

Spark OK, no Injector signal – Follow the ECU harness plug input/output testing as outlined in the appropriate Bentley repair manual. There is likely a wiring problem or the ECU may be faulty.

Gary19964 months ago

This answer is applicable for many BMWs in addition to the one listed below.

MechExp4 months ago

NO – Trace this circuit back to the ignition switch, including the switch itself. The switch should be sending 12-volts to terminal #86 when in RUN and START. You likely have a bad switch or a short or open circuit in this wire run.

Corrie19993 months ago
This problem has been solved

- see solution here