BMW M42

[Topgun]

Hello again
posted a few years back it seems , but I now have my M42 engine back in and my problem is with the passage of time and the fact I was daft not to mark which plug went where I am struggling to remember this , I have a s60 pro and there is one spare connector plug ?? so I have 2 two pin plugs which go to air box , and temp sensor , then one three pin with a red band on it which goes to throttle sensor , The engine is not using a cam sensor only a crank sensor (another 3 pin with a yellow band )so I have one three pin with a yellow band spare ?
I realise I may be clutching at straws so to speak but if anyone has similar I'd be grateful for advice (apart from mark everything before you take it off )
thanks

[stevieturbo]

You'd really need to ask whoever made your loom, or if they have a wiring schedule etc


When you connect to the ecu, are all the sensors you need, behaving as you would expect them to ?

[Topgun]

Hi thanks for your reply , we haven't tried starting her yet , and I have no wiring diagram so guess it will be a suck it and see job then ??
t

[katana]

You don't need a running engine to check sensors working / outputting sensible numbers! And 'suck it and see' isn't really a sensible diagnostic option when dealing with electronics! You can continuity check plugs against pins going into the ecu to work out what plug is intended for what function - its not that difficult.

[stevieturbo]

Hi thanks for your reply , we haven't tried starting her yet , and I have no wiring diagram so guess it will be a suck it and see job then ??
t

No, just do what I said to do. But the most sensible first step is connect to the ecu and see if everything makes sense

Or if really stuck, just bell the wires out from the random plug, to the ecu plug to see where they go.

[Topgun]

Ok
thanks for your replies they really are appreciated , I found a picture fortunately so was able to get them all in place , one was a spare it would seem , however we tried starting her and have no spark ?? what the mechanic found out of place was the three wires going to the coil pack are all live ??

I will print off the wiring diagram and investigate further
thanks again

[stevieturbo]

No, just do what I said to do. But the most sensible first step is connect to the ecu and see if everything makes sense

And I repeat again


Faffing about and guessing is not going to be productive.

And depending on the type of coil, seeing an apparent 12v on supply and trigger wires is not uncommon with the engine in a stopped state and ecu powered up

Has the "mechanic" ever worked on a fuel injected car before ?

[Topgun]

Hi
thanks for your reply .
OK with regard to the coil I spoke to Alex and he confirmed it is suppose to have 3 lives , I have since found the wiring sheets for the car and whilst I am no expert I am of the opinion that all is as it should be, I have not touched anything since the engine was removed apart from wiring up a lamp pod.
the only wires I removed were the plugs (no sorted )and the starter and alternator wires ??.
I have installed the DTA Software and all seems well with the connectors as they should be All earths are fine, however I still have no spark at the plugs ? I have run the diagnostic on the coli and injectors , I can hear them firing but I do not know what the coil is suppose to show , nothing appears on the screen ? , never had a coil fail before so wondering if to try a replacement but its been kept dry in the car .
The mechanic is a BMW specialist but unfamiliar with programable units like this .

thank you again for your advice it is always appreciated
regards
Bryan

[stevieturbo]

It is not supposed to have 3 lives. But the ecu trigger wires may appear as 12v in their "off" state. That is not quite the same thing. The actual live power supply will indeed be 12v.

So how have you tested and confirmed no spark ?

What do you mean you have run a diagnostic ?

Have you performed a coil test ? And has the ignition system been in a state where you can actually see/confirm there is a spark during this test ?

And of course taking precautions as noted in the manual to ensure you do not completely flood the engine during this test.

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

[Topgun]

OK
We tested in the traditional way of holding the plug against an earth , no spark

the diagnostic I refer too is running the injector and coil test via the software and as you say and as it tells me to make sure fuel pump is off , I can here the injector test but I am in need of advice as to test the coil please ?
I also tried the crank sensor test ,but all I got was some vertical lines , I need to study that more I believe , I have tried 2 different crank sensors to check
thank you again