NA M42 base maps

[the_bluester]

Following on from my trigger wiring question.

Does anyone have any sort of base map for an M42 with aftermarket management, using the stock injectors? I am happy to generate my own ignition timing curve and for now can be fairly conservative with it, but knowing the injector pulsewidths at wide open throttle would be handy to at least set up the basic shape of the fuel map to go on with.

we have bought an ITB manifold from Rama (Just waiting for it to arrive) and intend to fit throttle bodies we have had lying around for years, but anything that sets me up with a 70% tune out of the box would be handy, a couple of quick bursts through the rev range to log AFR with my wideband sensor to make sure that the engine is in a safe and not power sappingly rich state, a reasonable but conservative timing map and that will probably do for the foreseeable future.

[Delta]

I have a bunch of maps that I've tuned for my NA m42 for use with tuner pro. Paid quite a bit of money for some tuned files that actually turned out to be crap. Taught myself to read code to find all maps. Willing to help you out but I'm not on here that much

[the_bluester]

Actually,I  have just largely undone the usefulness of any base maps. In the fit up of the throttle bodies I worked out the the injector dimensions are the same as a set I had from another project, but which would have a significantly higher flow rate and more certain history than the originals in the car so we are using those. That throws any approximate pulse widths with stock injectors out the window!

It would be handy though to know a basic timing map, more or less what the full load advance was throughout the rev range so I can start from there and retard a few degrees for safety and add maybe 5 degrees at light load. The way time is going the car is likely to go to it's first event without a test day so safe and conservative will be the go.

[Delta]

Do you know tunerpro? If i get you the correct stock map you could pull a couple degrees timing and alter the fuel tables to run larger injectors (there isnt an injector constant like in some other programs/ecus).

[the_bluester]

Actually I am fitting a Haltech E11 from my other car (Which will see a new Motec ECU next year among other things) so it is all from scratch more or less. I should be able to build a conservative map for it to be on the safe side.

[MLM]

HI Bluester,

I have a ing map for a stock + ITB and exhaust M42 running a link ecu. PM me your email and I will send a screenshot of the map.

Cheers
Matt

[cristimm]

Following on from my trigger wiring question.

Does anyone have any sort of base map for an M42 with aftermarket management, using the stock injectors? I am happy to generate my own ignition timing curve and for now can be fairly conservative with it, but knowing the injector pulsewidths at wide open throttle would be handy to at least set up the basic shape of the fuel map to go on with.

we have bought an ITB manifold from Rama (Just waiting for it to arrive) and intend to fit throttle bodies we have had lying around for years, but anything that sets me up with a 70% tune out of the box would be handy, a couple of quick bursts through the rev range to log AFR with my wideband sensor to make sure that the engine is in a safe and not power sappingly rich state, a reasonable but conservative timing map and that will probably do for the foreseeable future.

There you go. Stock data from M42B18 E36:

[the_bluester]

Ta, though the fuel mapping is difficult to compare. looks like the factory used VE based tuning for the fuel.

Had the car nearly started yesterday. Very close in fact, but flooded it out while trying to work out some kinks (Some mapping oddities while getting it running meant that it was heavily over fuelling, running to around 7ms injector times when cranking where at idle I would expect 2ms or less. the injectors are for a six cylinder engine but if you divide it out they would be for a 2.5L four or so)

The biggest kink though is getting the timing right. After nearly 20 years of faithful service last night was when my timing light decided to pack it in, before I would work out the proper tooth offset. I saw 114 degrees mentioned on this forum as the offset from the missed teeth but the few flashes I got before the light stopped working (With the ECU timing locked to TDC) looked like around 18 degrees. I have to play around again tonight once I get my new timing light and work out the offset that works. I also need to get my oscilloscope on it to check that I have the trigger slope set correctly. Looking at the post here http://www.m42club.com/forum/index.php?topic=18999.0 I might need to change to triggering to the rising edge as I have used the yellow wire for the signal to my ECU from both triggers. That might explain the timing mismatch too.

It should start at 18 degrees advance so I will probably lock at 18 next time to work on the timing, three teeth from the TDC mark is easy enough to count and it would be lucky to run at TDC and with messy mapping too.

Hopefully I can report back success and have it at least starting and idling tonight.

[the_bluester]

No good news to report on this little project yet.

I am having major issues getting the triggering to work, sometimes it appears OK and I get all keen, then without changing settings it stops triggering properly and I stop getting ignition pulses. I am getting some curious trigger diagnostic readings. By my working I should see 118 trigger events between homes (Crank pulses versus cam pulses) but my ECU trigger diagnostics alternated between 57 and 117! I can't figure that bit out. With ho I have wired the sensors I should be using rising edge triggering but if I set that I get no triggers at all.

I am considering rebuilding my ECU setup from scratch with a new base map file and ignore everything but the triggers until and unless I get them sorted reliably (I will have to pull out the spark plugs, I am eating my available batteries every day in about 20 minutes and then that is that for the day while I recharge them)

There has been a fair bit of temptation to set fire to this thing in the last few days. I have just thought of a possible issue now which might be messing things up but it would be poor ECU firmware is that is the case. The car the ECU was last used in had hall effect triggers and I had to use the internal pull up resistors. That option is not available in reluctor mode, but maybe they stay enabled unless I disable them in hall effect mode before setting reluctor mode and are messing up my signals.

[the_bluester]

As an update for anyone interested. The problem has turned out to be the cars factory coils. The drive current required must be much higher than the Haltech branded driver (Huco I think) limits to. I put the timing light over the coil primary leads out of the driver and got nice regular flashes in time with each compression stroke. Put it on a spark plug lead and nothing. I bodgy wired a HEC17 coil to one of the connectors and cranked it abd BOOM.... Spark!

Project is on the backburner for a couple of weeks now as we have borrowed a car for the event it was being prepped for. The temptation is there to buy more connectors, cable, new coils ETC but I just don't have time to make it work. We lost a month trying to source a replacement cylinder head when the "Honest" owners failed to mention the water use (Three nice big cracks, the ferals must have boiled it stupid) and the time lost was just too much to overcome.

[Darky]

Interesting about the current requirements
Does sort of make sense though
I wonder if that would be the same on the coil on plug set up some of us have. I doubt it!

Thanks

[bmwman91]

The M42 coils are "dumb" coils and require high current drivers to work. Some work I did with an oscilloscope indicates that whatever is driving the coils needs to be capable of delivering 8-10 Amps and clamping a kickback voltage from the primary down to 450V or less. So, basically you need a dedicated ignition driver transistor for each coil. Haltech, Megasquirt, AEM and just about all of the current stuff on the market will NOT drive coils like this directly* and you have to build/buy a quad coil driver module. The QuanSpark module sold on DIYAutoTune is a very economical option.

A lot of newer cars use "smart" coils which have the driver circuitry built into the coil itself. Some can run on a 5V logic level signal with minimal current (a few milliamps) and some use a low-current 12V signal to trigger. None of these will work with the factory wiring harness without a fair bit of work though.


*VEMS seems to be the only stand-alone ECU out there with built-in high current coil drivers.

[wazzu70]

For the factory maps I assume the X-Axis is a 2bit 0-255 scaled value for engine flow rate?

Do you know what conditions dictate map 1, 2, and 3?

Thanks for posting, I havent ever seen the factory cal.

[the_bluester]

I had completely lost track of this thread. The car put itself on the backburner for quite a while due to giving me hell getting it running which turned out to be coil wiring related. I went to a set of Chev LS1 coils and had almost the same problem. It would fire then the ignition would go haywire with random sparks and the trigger diagnostics going nuts.

Turned out to be a dud wiring diagram which indicated to ground the coils (Both pins, there are two on LS1) to chassis ground. I moved the aux ground ground to the ECU sensor ground and suddenly the trigger is stable and ignition is like it should be. Ten minutes of work with roughing in a tune and it is like this.

https://www.youtube.com/watch?v=tcsw4tWXbNg

[the_bluester]

So, having gotten this car running I had left it at that for a bit as I was prepping a different car for some track fun.

I returned to this car just seriously enough to start roughing out a tune and to get it idling and free revving properly. Check, no problem, but now and again the car would just stop. It would not do it often enough to start tracking it down.

Roll forward to the weekend just gone and I go to start it to fiddle, no fire! Dead fuel pump. Locked up solid by the sound of it. All I get is a little "Clonk" from within the tank. Pulling the connector and powering it directly with a batter in both forward and reversed wiring, no difference. Seems it has seized.

Does anyone have a part number handy for a pump for one of these (E36 318is with M42 engine) as a replacement for the pump only rather than a complete replacement of the pump and fuel sender assembly?