Cranks no start

Tiny
SUNSARO67
  • MEMBER
  • 2004 BMW 525I
  • 2.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
Engine was missing and while testing for spark using a grounded test light, without inserting the spark plug into the coil, I cranked the engine. The ignition fuse (30A) was blown. After replacing the fuse car cranks but no start. All six connectors of the wire harnesses, there is 12v at the power (red) wire. Ground (black) looks okay. The third wire color is different on all six harnesses.

Before suspecting the crank position sensor I want to make sure the coils are good.

The connector socket on the tip of the coil has the triangular shape with 3 pins. After identifying the pins with the corresponding wires did the bench test. I gave 12 v to the power pin and grounding the top pin of the coil, tried to trigger the coil with the powered test light but to no avail.

Is there any method to bench test the COP?
There is fuel.

Have I damaged the coils while testing for spark? I understand the transistor is inside the coil.

The crank sensor was a cheap one that I installed couple of months ago.

Please advise.
Friday, July 24th, 2020 AT 7:01 AM

20 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

What you did shouldn't have hurt anything. As far as the inexpensive crank sensor, there is a good chance that is the issue. However, here are the directions for testing the secondary signal for the coil:

_________________________

2004 BMW 525 (E60) L6-2.5L (M54)
Checking Secondary Signal for Stationary Ignition Distribution [REP-REP-RAE3612-1213A06 - V.1]
Vehicle Power and Ground Distribution Testing and Inspection Component Tests and General Diagnostics Checking Secondary Signal for Stationary Ignition Distribution [REP-REP-RAE3612-1213A06 - V.1]
CHECKING SECONDARY SIGNAL FOR STATIONARY IGNITION DISTRIBUTION [REP-REP-RAE3612-1213A06 - V.1]
Repair instruction
Checking secondary signal for stationary ignition distribution
REP-REP-RAE3612-1213A06 - V.1

12 13. Checking secondary signal for stationary ignition distribution
image
Special tools required:

12 7 030

Engine Test Step 10

Remove ignition coil. Clip Special Tool 12 7 030 on relevant ignition coil to be tested. Clip high tension clip around ignition lead.

Pic 1

Connect earth lead of adapter to vehicle earth and ignition coil. Connect up diagnosis connector.

If trigger signal is not present (terminal 1), connect black clip of universal adapter cable to pin 1 of primary adapter cable.

Pic 2

Produce a stationary signal by pressing key R on the tester.

Note:
Neighboring ignition leads could produce interference on the screen of the oscilloscope.

Refer to the fault memories of engine control units for additional troubleshooting.

Interrogate fault memory and its fault reports - refer to Electrical Troubleshooting Manual.

Let me know what you find. Also, let me know if there are any diagnostic trouble codes stored.

Joe
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Friday, July 24th, 2020 AT 5:53 PM
Tiny
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Thank you Joe for your advice.

Unfortunately, I do not have the special tools or equipment to follow your guidance.

In the mean time I noticed that one of the connector in the E-Box which is in the left corner of the engine bay (Australian model) had the green stuff. I started the vehicle after cleaning and reconnecting the corroded connectors. This time I noticed smoke from the engine. I found No. 5 ignition coil melting. Disconnected the coil and removed it.I could pull out only a portion of the melted coil pack with the secondary winding stretched out. The other portion seems very tough to pull out.

No diagnostic codes but the transmission fault message appears on the car display.

Could you tell me why the coil got burnt. Please help
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Wednesday, July 29th, 2020 AT 8:09 AM
Tiny
JACOBANDNICKOLAS
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Hi,

The only time I saw that happen was when the boot that goes over the spark plug was allowing power from the coil to arc which overheated it. Check the boot to see if there are any grey marks in it. Also, make sure there is no oil in to spark plug tube that can cause a short and failure.

Do me a favor. If you haven't gotten it out yet, take a pic so I can see what you are dealing with and upload it for me. Hopefully, I will be able to provide guidance.

Let me know.

Take care,
Joe
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Wednesday, July 29th, 2020 AT 7:41 PM
Tiny
SUNSARO67
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Thanks Joe. The pics are attached.
Pic 1, 2, 3 the burnt coil from cylinder 5.
Pic 4, 5 Coil from cylinder 6 for comparison.
Pic 6 top view of the rocker cover area.
Pic 7 the spark plug well with the left portion of the coil in cylinder 5.
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Thursday, July 30th, 2020 AT 8:52 PM
Tiny
JACOBANDNICKOLAS
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Wow! That is certainly melted. Are you able to get long needle nose pliers down in there to remove it?

Once it is out, I need to know if there is oil down in the plug well and if you see any grey marks on the black rubber boot.
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Thursday, July 30th, 2020 AT 9:00 PM
Tiny
SUNSARO67
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I couldn't remove the part of the coil pack which was stuck in the spark plug well using the long nose pliers as it was very stubborn. I removed the rocker cover then I was able to drill the filling of the coil pack, a cement like thing. Then I used the pliers to remove. I couldn't see any oil in the well.I also notice that the damage in the coil pack is half way in the middle. Pics attached.
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Saturday, August 1st, 2020 AT 9:05 PM
Tiny
JACOBANDNICKOLAS
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Hi,

I looked at the pic. In all honesty, I suspect there was arcing where the rubber boot attached which caused it to overheat and melt down.

At this point, try replacing it and see if it happens again. I don't think it will.

Joe
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Saturday, August 1st, 2020 AT 10:54 PM
Tiny
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Thank you Joe, I will let you know the result.
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Sunday, August 2nd, 2020 AT 5:01 AM
Tiny
JACOBANDNICKOLAS
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Sounds like a plan. Take care and let me know if you have other questions regarding this.

Take care,
Joe
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Sunday, August 2nd, 2020 AT 8:18 PM
Tiny
SUNSARO67
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I checked the compression today. All cylinders show no compression. Is it because the engine was turning several times with the fuel not disconnected?
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Tuesday, August 4th, 2020 AT 11:42 PM
Tiny
JACOBANDNICKOLAS
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There is no compression in all cylinders? If you washed the oil from the cylinders with fuel, there would still be compression. Do me a favor. I need to hear it cranking. If there is no compression, something has caused the timing chain to jump or break and at least one valve in each cylinder is open. I'll be able to tell by listening to it. Make sure all spark plugs are replaced before recording it.

Here is a link that shows how to do a compression test. Let me know if this is how you did it.

https://www.2carpros.com/articles/how-to-test-engine-compression

Take care,
Joe
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Wednesday, August 5th, 2020 AT 10:30 PM
Tiny
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I poured some engine oil through the plug holes to all cylinders and now the compression is between 200-250 psi in all cylinders.
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Friday, August 7th, 2020 AT 9:05 PM
Tiny
SUNSARO67
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There is a stage 4 lock down in Australia and there is delay in receiving the parts. I will let you know the result after replacing ignition coils, spark plugs and rocker cover gasket.
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Friday, August 7th, 2020 AT 9:09 PM
Tiny
JACOBANDNICKOLAS
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The compression sound great! Not sure what a stage 4 lock down is, but I look forward to hearing if you get it going.

Take good care of yourself,

Joe
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Friday, August 7th, 2020 AT 11:12 PM
Tiny
SUNSARO67
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Hi Joe,

I replaced ignition coils with after market ones. Now number 1 cylinder coil becomes boiling hot. I checked the number 1 spark plug in another car. It looks good. Before installing the new coils I brought an ignition coil from a junk yard and tested along with the other five unburnt old ones that were in the car. In this test I installed the junk yard one in no. 1 cylinder and noticed that coil was boiling hot. Just after couple of cranks.

Earlier the coil in no, 5 got burnt. There is possibility that the spark plugs got swapped when I reinstalled them after cleaning.

What you think is the cause for the coil becoming boiling hot?

Joe, Here in Australia there are restrictions for the public on going out of the house due to the Covid19 issue and most of the shops are closed under the stage 4 restrictions until mid of next month.

I may receive the spark plugs via the post today.

Thanks Joe.
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Tuesday, August 18th, 2020 AT 12:37 AM
Tiny
JACOBANDNICKOLAS
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I read what you are going through again. I found a technical service bulletin to a specific brand of coil packs that had an insulation issue. Check to see if you have Bosch or Bremi coil packs. See below.

Reduced ignition firing power of BREMI coils due to coil internal insulation deterioration.

Only coils manufactured by BREMI are affected. BREMI coils are easily recognizable by the all black, shiny housings.

Important Note:
E46 M3 and E36/7 M roadster/coupe vehicles with S54B32 engines are not affected by this Service Information. Only BREMI coils should be used on S54 engine. Please refer to SIB 12 02 04 (02/2005) in case of ignition coil failure on M3/M roadster/M coupe vehicles.

Let me know.
Joe
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Tuesday, August 18th, 2020 AT 9:32 PM
Tiny
SUNSARO67
  • MEMBER
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Hi Joe,

Thanks for your reply.

I disconnected all coils and removed the fuel fuse. Connected the coil which I assume the good one from the old. Connected a new spark plug to the coil with a good ground and cranked the engine. I repeated the test to all cylinders with the same coil and the same spark plug. I noticed the following:

no 1. No spark, coil becomes very hot
no 2. There is spark
no 3. No spark, cop; becomes very hot
no 4. There is spark
no 5. No spark, coil becomes very hot
no. 6 no spark, coil becomes very hot

Do you think that the computer has gone bad?
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Friday, August 21st, 2020 AT 10:06 PM
Tiny
4DRTOM
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Hello,

I've been reading on your issue it's very interesting. When this started it was running then you popped a 30 amp fuse, that's a pretty big deal that harness running those injectors might have a short in it. It might be a good idea just to take a look at where it, especially the spots that would have been moved while you did the coil changes and where they all meet. Something shorted that had a lot of power to a solid ground short to do that. Which fuse did it pop?
Tom
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Friday, August 21st, 2020 AT 11:39 PM
Tiny
SUNSARO67
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Thanks to Tom and Joe.

Found the problem in the ECU. Something went wrong and some of the coils get constant ground connection through the ECU and a big current flows through the coils making them hot.
I need to replace the ECU now. Do I need to reprogram?
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Sunday, August 23rd, 2020 AT 10:52 PM
Tiny
4DRTOM
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Hello,

Yes, for a BMW you will need to have the VIN number and bring that to the dealer with the ECU you get to have it flashed with the appropriate info or the keys wont work among other things including the cars correct mileage. BMW is pretty heavy on that, they may even make you bring them the title to prove it's yours. Be ready for that.
Tom
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Sunday, August 23rd, 2020 AT 10:59 PM

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