E36 M42 trigger wiring

[the_bluester]

Hi all, first post in here. Apologies for it being questions straight off.

A mate and I recently bought a 1993 E36 318is cheap as a car to have a bit of fun on the track while I do some reasonably major redevelopment on my other track car (A HR31 Skyline)

Having first up found what seems to be a common malady with the M42 (A cracked head, badly in this case, some people should not be allowed to have cars!) we have sourced a good head (Which took some doing) and fitted it but the car now refuses to run after everything is hooked up. It floods on initial cranking, the only way to get it to start is to crank it until it floods then pull the fuel pump fuse, crank it until it fires up then race around the other side (I am in Australia, so a RHD model) and put the fuel pump fuse back in before it dies. It will then idle and will rev if it is done gently but it has no power and is going lean under load (Backfiring through the inlet) It ran OK before the head came off.

To simplify my life (Unless someone on these forums can point me to something stupid or simple I may have missed, I have already removed half of the manifold again to check all electrical connections are back on and in their right positions) I am looking at removing the Motronic DME and replacing it with an E11 Haltech which is coming out of my other car. I have tracked down a wiring diagram and plan to cut into the engine loom in the ducting above the engine and fit some DT connectors, and then run my Haltech loom to the same point and terminate in mating DT connectors. That way I will be able to rebuild the engine loom later if/when the car has an engine transplant.

What I have not been able to work out is the arrangement of the crank and cam triggers, specifically, are these hall effect devices or simple inductive pickups? The wiring diagram I have found is unclear and shows two connections to them, which would indicate an inductive sensor, then another page shows them as having a 5V reference via a resistor on one line which I would have expected as a positive supply to a hall switch. There are three pins in the connectors on the engine loom but that may be a pair of signal wires and a shield.

TL/DR version, are these inductive pickups as they appear to be?

My only other question relates to the ignition coils, they appear to be a plain old ignition coil with the driver circuitry built into the DME itself, I have not had a chance to meter them out yet to check. Is that the case, in which case I need to buy a coil driver module to get it up and running.

Thanks for any help that people might be able to offer.

[the_bluester]

OK, missed the blindly obvious thread in this sub forum regards the sensors. The oscilloscope traces look like inductive sensors to me.

That leaves my only question for now as confirmation that the coil driver circuitry is in the DME so I would need to buy a quad channel driver.

[MLM]

Hi,

Can confirm coil drivers are on the dme. I built a 4 channel driver using bip373 kits from diyautotune if 4 channel drivers are hard to get or eye watering expensive as they in my part of the world this ua an economic solution.

Matt

[the_bluester]

Thanks, I thought that would be the case just looking at the coils, just wanted to make sure that the drivers were not hidden away somewhere that I had not found yet. A quad channel Huco driver is not cheap but not horribly expensive here so I will just buy one of those for it, it will cost about $300 AUD and from the supplier I am looking at comes with plugs, pins, boots and a heatsink. It will run the M42 for the foreseeable future and if we repower it (We are thinking of an SR20 turbo Nissan engine) then I can get suitable coils for that or even just keep using the BMW ones.

The repower issue may never come up. It depends on if we can forgive the M42's head fragility, it is not a good sign when it took a good engine place I have dealt with for decades a month to find one that was not cracked. I think a lot of the problem is that these cars are now worth very little in Australia and people who should really stick to old Holdens with cast iron everything are getting hold of them and neglecting them to death. A cast iron V6 will usually live through a bit of a boil but all the signs are that the M42 likes it about as much as my Skyline would, meaning not at all!

After all of this I hope the car is fun handling wise (It is not going to feel fast after stepping out of a Skyline that weighs about the same but has the best part of 400HP)

[the_bluester]

I thought I would add to this one. I am in the middle of fitting the E11 tot he car, I have found which is the speed input pin to the DME, but I do not have any information on its format. Does anyone know if it is a digital switched output from the dash or is it a reluctor type signal straight from the gearbox? Second most important question, does anyone know how many pulses per kilometer it produces? I am hoping for 20,000 or so for good resolution.

[MLM]

I believe its fed directly from the diff using a magnetic pickup on a "chopper" wheel. A image search should give the number of pulses per revolution.

[the_bluester]

I found a wiring diagram that indicates it is an output from the dashboard to the DME (and the sensor is an input to the dash) and looks like it should be a TTL type signal there so I should be able to use it in my Haltech. I will just need to figure out the pulses per kilometer. So long as it works to begin with it will be easy to sort. The dash that is going in the car has a GPS input (Which we will not be allowed to have connected at the first event the car is going to) so as long as I get a usable reading I can compare the wheel speed generated and GPS speeds and adjust the pulse count until it is right. I want to set that up so we can have a working speedo at the cars first event as there is a pit lane speed limit of 40KMH and it is enforced fairly tightly. Pretty hard to judge 40KMH at Phillip Island where even a fairly stock E36 is likely to see somewhere above 160KMH in a number of places on the track and the car will be out there for about a half hour stint.

[the_bluester]

I am currently at a bit of a standstill with this car. As I have posted elsewhere I am having some issues with the crank trigger, it is doing some really strange things when I look at the ECU logs, by what I can tell I should see either 58 (Maybe 59, I don't know if the Haltech will see the missing teeth as a single tooth) triggers between home events, or 116 (or 118) if the home count is to the cam trigger.

When cranking, depending on settings in the ECU I either get 255 (Indicating it is not getting a home) or alternating between 57 and 117!

Has anyone using aftermarket management used a hall effect trigger on one of these with the original 60-2 wheel on the crank? I am looking to get away from the VR sensor if I can. I have found some options, including the high speed version of the Honeywell GT101DC (The standard one will not trigger fast enough for a 60 tooth wheel at high revs) of a holley one. Getting a niice clean square wave ito the ECU would eliminate a lot of trigger issues.

[the_bluester]

I have been chatting with Haltech, firstly they reckon the coils should work OK and weak spark is usually a case of wrong polarity (I wired it matching BMW) too little charge time (I ramped it up to silly charge times at one point without seeing any difference) or sometimes wrong edge setting (I can not recall if I tried both there, something for tomorrow)

My other issue, they have recommended staying with the VR sensor as they reckon that the BMW 60-2 wheel works poorly with hall effect sensors, and that the count between triggers alternating 57-117 is normal. I can not find the logic in that in how he put it in the email but I will take it as read that it is normal. The count being down from what I expected by one is because the trigger counter starts from zero at the first trigger so that is normal too.