Batch injector wire for Motronic 1.3 or mega squirt in what order?

[hunneman]

I created a wire harness to my M90 engine to accept Motronic 1.3, question If anyone can help me confirm that the injector wires follow cylinder order, and not the firing order or the other way around. Current i have batched injector wires 1,5,3 on the A and 6,2,4 on B. Any help is much appreciated. Thanks

[Mike W.]

I may be full of it on this one, or maybe not. I thought one of the advantages of M1.3 was sequential injection, not batch. And I may just be thinking of L-jet/M1.0, but IIRC they fire at the same time, once per revolution or twice per ignition cycle, but 3 on one circuit so to speak. Also since you're doing an M90 I assume you have high impedance injectors? M90s came with low impedance which will burn up the FET or whatever it is that fires them. Big deal, 3 or 16 ohms.

If this is all old news to you, just ignore it.

[hunneman]

You are correct for the L-jet is was sequential.
Yes i have installed 24lb high impendence injectors..
My question is do the injector wires in which order do they get installed 1,3,5 last 3 cylinders, and 2,4,6 the first 3 cylinders?

I'm stumped on this
or do they go by cylinder order injector wire 1 to cylinder 1 and injector wire 2 to cylinder #2 AND SO ON Cylinder 1 being from the front of the engine.

I may be full of it on this one, or maybe not. I thought one of the advantages of M1.3 was sequential injection, not batch. And I may just be thinking of L-jet/M1.0, but IIRC they fire at the same time, once per revolution or twice per ignition cycle, but 3 on one circuit so to speak. Also since you're doing an M90 I assume you have high impedance injectors? M90s came with low impedance which will burn up the FET or whatever it is that fires them. Big deal, 3 or 16 ohms.

If this is all old news to you, just ignore it.

[Mike W.]

If it's batch, I don't think it matters.

If it's sequential, usually, wires have a length and bend to them which really strongly suggests where they go.

OK, I found a diagram I downloaded long ago but it doesn't show sequential even though it's nominally '91, but perhaps from Russia and they may have gotten slightly different stuff there. But it's something. It does show 1-3-5 on one circuit and 2-4-6 on the other, but again, I don't think it really matters.

[hunneman]

Mike, this diagram is spot on.. so the injectors wire follow the firing order on ECU the pin#16 is the batch for the 1,3,5 firing order, and Pin#17 is for the second batch firing order 2,4,6..

thanks for your help on this

[turbodan]

I've played with injector staging over the years. Seems to make very little difference in practice. The bigger issue cannot be solved without a cam sensor as the ecu doesn't know which TDC it's seeing. Might extend cranking times, though I think injection occurs on more frequent intervals during cranking so that may not be a factor either.

Megasquirt can certainly do fully sequential injection. I'd take advantage of it if the provisions were there but it's probably not worth the effort of implementing it on these engines. I imagine it would improve idle quality and emissions. Idle can be pretty good with batched injection though.

[hunneman]

I think mega squirt will make a significant difference compared to L-jet from the mid 70's, in addition as you know with a motronic or mega squirt wiring setup has a cylinder ID sensor (coming off of the cap plug wire #6) and a magnetic crank sensor (mounted near the front crank wheel) this should improve crank times and performance.. I also am installing a AEM Digital Wideband UEGO Gauge 30-4110 just need to figure out on the ECU which pin#.. Having a hard time figuring it out, I believe Pin # 28 is the input for O2 Sensor..do you have any knowledge..

I've played with injector staging over the years. Seems to make very little difference in practice. The bigger issue cannot be solved without a cam sensor as the ecu doesn't know which TDC it's seeing. Might extend cranking times, though I think injection occurs on more frequent intervals during cranking so that may not be a factor either.

Megasquirt can certainly do fully sequential injection. I'd take advantage of it if the provisions were there but it's probably not worth the effort of implementing it on these engines. I imagine it would improve idle quality and emissions. Idle can be pretty good with batched injection though.

I believe mega squirt both idle and emissions...

[turbodan]

Pin 28 in the Motronic 55 pin connector. Pin 23 in the MS2 DB37 connector.

The thing with megasquirt and cranking time is the few fractions of a second that it takes before it picks up the trigger wheel pattern and begins fueling. On datalogs you can see when cranking actually starts by observing the dip in battery voltage and there is always a delay before it registers RPM. I think motronic does a better job here. Sometimes ms2 takes a hair longer than I think it should. Oddly enough, only when cold. When hot it often lights off immediately.