it would depend on how it intercepts and alters the signal.

with our megasquirt project, we physically cut the harness wires that control the injectors and ignition and then send signals back to the stock coils and injectors. We have to program the MS to know certain engine parameters (displacement, rotors, etc) and tap certain sensors such as RPM, MAP, engine temp etc... so it knows how much fuel and spark to add.

It could be that rather than enter all that engine data, the emanage ultimate uses the stock signals as a reference point, that way it has a idea of how much fuel and spark to use, since it may not know the size of the engine and its various operating parameters. This is just a guess, but it would explain why it still needs the PCM signals, unlike the MS. This would be one way to set up a sort of universal ECU.

there is more than one way to skin a cat, and it all comes down to whether or not the PCM can force changes through the ultimate, which it sounds like it can't

 

The OEM PCM will still fight the Ultimate if you don't spoof the OEM WBO2S.
However, the Ultimate can fight back unlike the Blue or Gold.
With the use of an external WBO2S, the Ultimate will see when the OEM PCM is fighting back and make adjustments to compensate.
The Ultimate can make much larger shifts in fuel trim than the PCM can, which is limited to about 30%.

I got mine installed last night in about one hour. It is basically just doing what the Gold was doing at the moment. I'm going to add some wiring to both the Profec (which is now out of the E-Manage loop since it isn't compatible with the Ultimate) for TP, coolant temp and vehicle spped, as well as the same for the Ultimate.

 

would tuning based on boost with the pressure sensor harness help at all?

 

Overall, tuning for pressure is a better/easier way to do it, but it won't do anything to prevent the ecu from adapting and changing your tune. For most people to get power out of the Renesis, you really have to remove the stock ecu from control all together.

 

crap.

guess that means I'm out $1600 or whatever the interceptor costs . . . unless there's another option?

 

What are you talking about here? The entire point of the interceptor is it replaces the factory ECU for fuel and timing altogether. That's the pont of being able to ignore LTFT.
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yes and it costs $1600, hence, I have to pay $1600 to get it.

I've been talking with more of the Celica guys - here's what they had to say.

Basically, piggybacks don't work on the Celica because the computer is too smart, it learns and goes back to its original settings just like our car.

HOWEVER - when the e-manage is used in conjunction with the ignition harness, the ignition input goes DIRECTLY into the e-manage, and then the e-manage spews out the information and controls the injectors, controlling fuel delivery, and overriding the computer's desire to correct, so it worked in Celicas - I'm going to try this and let everyone knows how it goes - if so it could be a nice $35 fix for the e-manage, rather than blowing $1600 on the interceptor.

 

So you're saying by using the ignition harness the emanage is able to generate its own waveform to control the injectors? If so, no way. The emanage is designed to augment the factory signals and cannot generate its own. As long as your augmenting factory signals, adding 20% or 80% or whatever to a base signal, then the factory ecu can alter its base signal to compensate and hence still has a great deal of control over whats going on. It can't completely undo the emange's alterations, but it can change them by up to 30% or so.

I'm not sure about the ignition harness, I am not using it, so I don't know if the emanage can generate its own ignition signals or if it modify's factory signals. If it can generate its own signals, thenit could give good improvements, at least you could prevent the ecu from retarding timing. But it could be extremely risky and I wouldn't do it. If the ecu leans out your A/F without you knowing and the engine begins knocking the knock sensor won't be able to retard timing to protect the engine. If you do, at least make sure you have a wideband O2 installed and watch that cel.

MazdaManiac is using the ignition harness I believe, you can contact him for more info.

 

Ah, enlightenment dawns. The way your sentence was structured it implied you had bought an inteceptor and now found out it wouldn't work the way you wanted.
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Not exactly. It can control one set of injectors independently and is wired to do so on the GReddy turbo. That's the "sub injector" map. The other injectors are adjusted by the emanage adding length to their pulses ("additional injection" map). Hence, it only adds fuel and can't directly subtract it because it can only lengthen the ECU pulses when it recieves them before passing them to the injectors.

 

sorry when I said ignition harness I meant injector harness

I really don't understand how any of this stuff works, its just what my buddy told me.

I just turned my boost controller up and let the ECU sort it out - its working fine so far.

God bless the nanny knock sensor.

 

While that's true that the emanage can generate the waveform to control 2 injectors, its dependence upon the factory ecu for the other 4 greatly diminishes the usefulness of it. If you go squirting more fuel through the auxillary injectors, the ecu will pull it back out from the primary and secondaries. Granted it won't pull it all, but you don't know how much it will pull.