Odd Fire TBI

[Willys43]

It looks like everything is working right. TPS,MAP,ETC signals look good. Both computers are outputting spark signals and injector signals. I'm unable to tell if the spark and injector signals are staggered from even to odd cylinders because they're too close together. The RPMs look right. I am able to create and flag errors by manually varying input signals. Fuel pump relay works properly. Computer seems to be adjusting the timing. Guess maybe it's time to start setting up the harness I'm gonna use.

[Six_Shooter]

I also have to question the dual ECMs...

You're just setting yourself up for a world of hair pulling nightmares trying to run two ECMs on a single engine. As Delcowizzid was saying there's an HEI module that already does everything you need in sending puleses at corrected times to the ECM, while providing the oddfile spark.

Another, better option than going dual ECM is to go to an aftermarket ECM that WILL run oddfire, such as a Megasquirt. You'll spend less money and time in the end just going with something that will be known to work than trying to make some frankenstein of a mishmash of parts to get something that will likely only work marginally at best.

Like has been said, the closed loop fueling will be fighting each other. unless each bank is COMPLETELY isolated from one another, and treated as two separate engines, no no chance of fuel that is commanded by one ECM ever being read by the O2 sensor feeding the other ECM.

Regarding the IAC, yes, one ECM will control it, and you only want one ECM to control it, however, the ECM that has no IAC connected will not like that very much when it commands an idle speed change and doesn't see it. Keep in mind that just because both will be the same ECM and will have the same BIN file does not mean that they will be in sync, that would take communication between them, which is not possible, since they were not designed with that in mind.

The only successful dual ECM applications I have seen are where each bank or sets of cylinders have been completely isolated from each other in both fuel delivery AND spark, where each section was connected as it's own independent engine that just happens to share a common crank with another engine. Trying to split the ignition control like this will just be a night mare.

[1project2many]

It looks like everything is working right. TPS,MAP,ETC signals look good. Both computers are outputting spark signals and injector signals. I'm unable to tell if the spark and injector signals are staggered from even to odd cylinders because they're too close together. The RPMs look right. I am able to create and flag errors by manually varying input signals. Fuel pump relay works properly. Computer seems to be adjusting the timing. Guess maybe it's time to start setting up the harness I'm gonna use.

Congratulations! I think you'd need a scope or another tool to display the spark signals and be able to tell if they're spaced appropriately. But if they're coming from different pickup coils then they should be timed differently. Have you made any changes to the calibration yet? Like changing the number of cylinders in the chip?

Any pictures?

unless each bank is COMPLETELY isolated from one another, and treated as two separate engines

There are several technical reasons why this is being treated as two separate engines on a common crank. If you are interested, they are here.

[Willys43]

Right now they are firing off of the same pickup coil that has had 3 points of the 6 pickup points ground off. Basically a 3 cylinder engine. The odd cylinder Chip is programmed for 3 cylinders at 0 degrees base spark. The even cylinder chip is programmed for 3 cylinders with 90 degrees base spark advance. The base BPW has been reduced from 181 down to 135. The Bin is from a 4.3, the 198 fireball is a 3.2 which is 25% smaller. I decreased th BPW from 181 x .75 to get to BPW of 135. If the single pickup doesn't work I'll take the factory pickup coil out and put two pickup coils in at 45 degrees. Anything else you can think of that I will need to change in the programming for start up? I'll post up a couple of pictures, it's kinda messy because I rolled up wires and tied them instead of cutting the longer wires I may need.

Six, I really really really like the last line on all of your posts��

[Willys43]

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Here are 2 pictures of my test board, The throttle body has been removed because it just sitting loose, and one picture of the adapter I have to make for the throttle body.

[Six_Shooter]

I'm all for oddball things, but somethings you just need to step back and look at and realize that they just aren't worth the hassle.

I'm sure you get the engine to run, but I see it being severely limited in the way it performs. It'll be a nightmare to tune, dual emulators would help there, which I know works for Nissan applications, but not sure if there's anything special in the XDFs to allow for that, or if you just need to enable the setting in Tuner Pro. I'm still not sure why you wouldn't just try using a single ECM on your engine and see how it runs before complicating things. The magic of oddfire happens in the ICM, not the ECM.

[Willys43]

[Partial QUOTE=Six_Shooter;58697] but I see it being severely limited in the way it performs. It'll be a nightmare to tune[/QUOTE]
Six, I would really like to see some documentation that supports this statement.

[Willys43]

Here are some pictures of a two computer harness ready for installation onto the Willys. I will cut and solder the wires on the engine side after they are properly routed and connected so the lengths will be right, and I'll wrap them up after its up and running to make sure I haven't left anything out. I used a donor harness out of a late 80's full size Astro van, retaining the factory grommet shown in the middle picture.
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