BMW M42

This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
stevieturbo
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Re: BMW M42

Post by stevieturbo »

If you were running the coil/injector test and doing as you say with the spark plug, then yes absolutely you should be getting a spark.

When doing the crank oscilloscope for the crank sensor etc, it will show vertical lines. You'd need to post the screenshot of the result. Although it seems mostly only Alex/DTA truly knows how to interpret what it says

But those are two separate issues. The coils should fire during the output test regardless of crank sensor.

Exactly what coil are you using ?

At this point it sounds like you'd need to test the ecu coil outputs with either an oscilloscope or a noid light should do, and again run the coil test to see if the outputs are actually doing anything.

I guess a regular test lamp might show something when connected in place of a coil, getting brighter as rpm's rise during the test. But Alex would need to confirm that. It wouldn't be the typical way to test, but should work ok.
Topgun
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Joined: Thu Jan 27, 2022 1:11 pm
ECU Model: S60 Pro
Firmware Version: 82.10

Re: BMW M42

Post by Topgun »

dta.jpg
ok , sorry for late reply , work , life etc
So its a zetec coil , set for wasted spark according to the paperwork I have , I have run the coil and injector test and I have a spark from the coil when using that test , however when I do a spark test when cranking I have a intermittent and weak spark ??, I have cleaned and checked injectors , is there a way I can check throttle sensor to see if fuel is actually going in ??
I enclose a pic of the crank sensor oscilloscope for you to see .
thanks
Regards
stevieturbo
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Re: BMW M42

Post by stevieturbo »

https://www.dtafast.co.uk/download_file ... Manual.pdf

https://www.dtafast.co.uk/download_file ... Manual.pdf

https://www.dtafast.co.uk/download_file ... Manual.pdf

You check the throttle position sensor, by looking at the ecu software.

the throttle position sensor does not inject fuel in.

Scope trace looks sensible, if indeed your ecu is configured to read that setup.
Topgun
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ECU Model: S60 Pro
Firmware Version: 82.10

Re: BMW M42

Post by Topgun »

OK
it seems i have a major fault somewhere .
As I said when I run the tests all is well , the plugs have a spark and the injectors fire , fans work etc etc
However when I try to start her on the button ,very weak spark and intermittent , no fuel going in , I have put a test light on the injector leads , nothing , no pulse , however when I stop cranking they show power for a few seconds ???

as I said , I have not changed anything since I took the engine out
anyone seen anything like this before , getting sleepless nights now ,
stevieturbo
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Re: BMW M42

Post by stevieturbo »

What shows power for a few seconds ? And exactly what leads are you testing ?

The simple fact during an actual ecu test all items work, means the wiring to a degree and ecu work fine.

So as I'm sure has already been said, do you see a solid 12v where necessary at coils and injectors during cranking ? Live wire only, tested against vehicle/battery ground.

Post a video, screen capture, whatever of the ecu diagnostic screen during cranking. Ensure to reset the screen/values first

Information is needed to even attempt a remote diagnosis.
Topgun
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Re: BMW M42

Post by Topgun »

ok I have tried again to get to the bottom of this problem but I am getting more confused ,
so as before i did a crank test I did as before with the spark plugs out to prevent straining the starter motor with a long crank , below is a screenshot of that , which is like to one I posted earlier ,
the second crank test I did with the spark plugs in , but now there is a vastly different reading , which I confess to having no idea about , just can understand the difference, if someone could explain please
thanks
stevieturbo
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Re: BMW M42

Post by stevieturbo »

Again, perhaps Alex is the only one to decode the DTA's scope traces, but it seems like gibberish really. Which is rather unusual when the no plugs trace is nice and clean

A real oscilloscope trace would offer more info to me. I just don't understand the DTA traces

And I repeat again.....what does diagnostic screen say, post a video of it during cranking. It will be showing multiple errors

Certainly with the trace like that, it will never start or attempt to start. What is causing it to turn to gibberish, not so sure. Whether interference from the ignition system itself ( never route HT or such wiring near crank or cam wiring and certainly never parallel too any ). But then if no sparks are occurring, then there should be no interference.
Or if it is a VR signal and your cranking rpm is very low...maybe that's a reason

But AGAIN...the diagnostic screen is there for a reason, it too will give info.
Alex DTA
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Re: BMW M42

Post by Alex DTA »

The first trace is fine. The second is showing a lot of noise.

Try again with plugs in, but coils disconnected.

Make sure the stud on the case is properly grounded as per the wiring diagram. It should be connected to pin 13.
Topgun
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Joined: Thu Jan 27, 2022 1:11 pm
ECU Model: S60 Pro
Firmware Version: 82.10

Re: BMW M42

Post by Topgun »

OK , I confirm the stud is grounded
I made 2 videos one of the diagnostic and one of the crank ,(with plugs in but no h.t leads connected ) strange but I get a different reading on the crank every time ??. I have no HT cables anywhere near the crank sensor

I apologies but im not savvy enought to compress the video down to fit on here so link to you tube

diagnostic test


Crank test

once again thanks for your help
stevieturbo
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Joined: Tue Aug 02, 2011 12:08 pm
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Re: BMW M42

Post by stevieturbo »

It shows no rpm when cranking, so it just isn't seeing anything it understands.

Also just hold the camera still so all the data can be seen without you zooming in different places.

Cranking voltage is quite low at around 9.0v, but I'd doubt that is the problem

Upload your map.

If you had a proper oscilloscope, I could certainly understand that better as to what is or is not being seen from the crank sensor and if it could be a valid signal.
I just don't understand the DTA scope itself and what the lines etc actually mean. Diag screen says it sees no rpm, no errors etc.....which just seems at odds when it is counting teeth to some degree and clearly cannot make sense of what it sees. So surely there would be some notion of both rpm and crank errors.

What type of crank sensor is in place ?
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