Adding an M800 to a car with early ADL dash. Wiring question

[Chris Wilson]

I have a sports prototype with a Formula Atlantic Toyota 4A-GE four pot in it. I bought it from the USA with an all singing and dancing ADL dash that the previous owner seems to have ticked all the options on, like 4 cylinder EGT probes, full data logging from multi axis G sensor, blah blah. The engine is on carbs with an American Electromotive ignition "ecu" which just has a few pre settable advance re RPM points. I have turbo charged the engine, and put it on sequential injection and a single throttle body with a MAP sensor. I have retained the 4 EGT probes. The car has a professionally made Raychem loom in it, mainly going to the ADL and the dashboard switches. I am putting my M800 on the car as the new turbo engine ecu. I don't know whether to try and keep most of the existing loom and feed the M800 some info via Can Bus, from existing sensors, from the ADL, or make a new loom, which will have to be home made due to costs, and the experimental nature of this project, or what? Can anyone advise the most cost effective way of keeping the ADL working, and adding an M800? I am new to this sort of stuff, but I have got my RB26 Skyline engine working fine on an M800, albeit with no ADL installed. I would like to keep the Raychem loom currently in the car pretty much fully intact in case this idea is a failure and I return it to N/A format on carbs and with the Electromotive ignition thing. Thanks!

I have also posted this to the ADL section of the forum as I am unsure where best it should lie.

[David Ferguson]

Since the ADL only has a single CANbus, I would look for any existing connectors in the current harness. Look at the existing ADL config for clues of CANbus based devices -- such as a BR2 beacon receiver, or a PLM. Also, the download port on the ADL is CANbus -- so you could splice into that for your ECU connection.

David Ferguson
Veracity Racing Data
Motec Dealer
USA

[Chris Wilson]

Thanks David, what I am thinking of doing is using the Can Bus to feed the following, existing, sensor signals which the ADL is reading, to the new M800, and the other signals required I will feed direct to the new ecu. Does this seem OK to you?

Existing sensors fed off a pro Raychem harness to the existing ADL dash:

Engine water temp
Engine oil pressure
Throttle position
Engine oil temperature
Engine fuel pressure (sensor change and re calibration as current sensor reads low pressure to twin webers, new set up is fuel injected)
4 x EGT probes, one in each manifold runner
Currently RPM is read off the Electromotive ignition box, need to find out if the crank trigger alone is connected to the dash, not sure...

The dash also reads one wheel speed, and a 3 axis G force sensor, and the lap beacon receiver, but these are not directly engine map related. It also feeds a Motec gear change light array.

New wiring needed:

Crank position sensor (existing) direct to ecu via screened cable.
Cam position sensor (new Hall effect) direct to ecu via screened cable.
MAP sensor (new) direct to ecu
4 x COP Toyota coils to Bosch igniter, then direct to ECU (original set up used the Electromotive ignition only box with 4 plug leads from the Electromotive box).
Inlet air temp (new) direct to ecu.
Bosh wide band O2 sensor direct to ecu (or via my PLM if I "borrow" it from another car I have}.
ECU power via diode protected relay for reverse polarity protection and a fuse.
Can Bus wiring from M800 to ADL dash

Can anyone see fault in this? 99% of existing Raychem loom is untouched, and critical feeds like crank position and cam position are direct to the ecu.

Thanks.

[David Ferguson]

While it's possible to have inputs going to the ADL, then fed to the ECU over the CANbus -- I would recommend that you connect ECU-required functions (like TPS and Fuel Pressure) directly to the ECU. If it were me, I would probably do the temps as well, since these are easy to wire - and it logically keeps all the engine-related wiring together.

If the ADL harness doesn't have a disconnect for all of it's engine sensors, then I would just coil them up and out of the way. If it does have a disconnect, perhaps you can just create wiring from the M800 to that sub-harness.

Of course, you could add a connector pair into the ADL harness to create an engine sub-harness.

If you're going to re-use the Electromotive crank trigger, then it will need to be tied directly to the M800.

You will just re-configure the ADL to get RPM from the M800 via the CANbus.

[Chris Wilson]

Thanks again for your considered and detailed reply David, much appreciated! I have not checked to see if there is a disconnect for the engine bay loom, but I suspect not, I am not entirely certain my project will be successful, so I am loathe to butcher such a nice, professionally made, and not to say costly loom, only to find I want to return the spec to N/A Formula Atlantic. Would the engine run ok for testing the turbo install and cooling needs feeding the Motec M800 via Can Bus from the sensors currently on the existing loom, or is so bad a practice I should just make a new loom as you suggest? If I was more confident in this project I'd just jump in and make, or have made, a new engine to M800 loom, complete, but I have "one of those feeling, if you know what i mean? I dislike wiring, and have only modest experience with wiring ecu's, so, despite feeling I have asked for advice and then immediately seem to be suggesting doing something different, I hope you can see that, to me, a lot of re wiring is quite a daunting prospect? Thanks!

[David Ferguson]

Since I design & assemble wiring harnesses, I don't see this as that big of a deal. I think the first step for your project is to understand what you have. If you pull the ADL harness out of the car (that just takes your time), you can send it to someone to properly install a connector pair. I'm sure this would be less than the cost of a pair or rear tires for that car (and you're gonna use a set of those every weekend!). They could probably supply a mating connector with M800 connector terminals wired. Then you just have add your injector, ignition, and crank/cam triggers and you'll be ready to start the engine.

Having a properly built M800 harness is also part of the cost of running an M800. Do it right the first time, and it will outlast the engine.

I don't know where you're located (but since you said "bought it from the USA", I assume you're not in the US), but there must be someone in your area that can build (or help you build) a decent harness -- how about your MoTeC dealer?

I just realized I didn't answer your question.

Will using the ADL work for prototyping? In theory it should as the data rate should be sufficient -- step one would be getting the ADL to M800 communication going. You just need the M800 power and the CAN bus. Using the Dash Manager and ECU Manager configure communications, and prove that you can get the values you need at the M800. If that seems to be working -- then wire up the M800 to the engine (ref/sync, ignition & fuel), and see if you can get it started & tuned. In theory it should work -- but do you really want your engine running to be dependent on dash communications?

[Holmz]

...

Will using the ADL work for prototyping? In theory it should as the data rate should be sufficient -- step one would be getting the ADL to M800 communication going. You just need the M800 power and the CAN bus. Using the Dash Manager and ECU Manager configure communications, and prove that you can get the values you need at the M800. If that seems to be working -- then wire up the M800 to the engine (ref/sync, ignition & fuel), and see if you can get it started & tuned. In theory it should work -- but do you really want your engine running to be dependent on dash communications?

I see your point Dave, but using the ADL should work and the more important messages would be on the lower addresses, there should not be too much latency. It is a 1Mb/S link so it is pretty immediate if you sampling is high in ADL.
Of course you are correct that it is theoretically better to have those sampled in the ECU, and then you could have other things sampled in the ADL like wheel speed, steering etc.

But it would be worth trying it over CAN (IMO) since that is all assembled.