[brokenboosted]

okay guys i get it the ford tfi has been done over and over again but trust me this one is different!
so i have a 90 f150 with a E4OD. theres lies the problem the Electronic controlled 4 speed overdrive auto trans. stand alone controllers are anywhere from 800 to 1500 bucks that i am NOT spending it on lol. The plan is to run the speedunio running the motor and the stock ecu (PCM) controlling the trans. so we get the pip signal is used to feed into the rpm in on speeduino with a diode but i need the pip (ignition) signal so the stock ecu will still see rpm to control the trans. Ive read (on here) that you cannot share signals so that means i couldnt share the pip signal between the two also causing another issue with sharing the tps signal (assuming using the power ground and signal on the speeduino for tps). i dont think ill need to share/split any other signals. Can i input the pip into the rpm in in the speedunio then use the tach out to pass along the pip signal to the stock ecu? if so can i do this with the tps signal too? Any other crazy ideas? Would my life be easier to just make/buy a crank wheel and hall sensor (like a 36-1) and if i did go new wheel would i still be using the spout input as ignition the same? After getting this figure out i think it should be very easy getting it wired and running.
i know poeple like psig and a few others a very tfi knowledgeable and i hope this takes off enough to get some answers.
Thank you all in advance

[dazq]

I think you have misunderstood what you read !
Sharing signals is perfectly ok if done correctly and has been done successfully many times.
Don't pass through the tach as the waveform would be totally wrong.
TPS if it is a normal 0 to 5v signal can also be shared without difficulty.
Iat and CLT will need the bias resistors on speedy removed to not interfere with the reading . Just calibrate them in TS with the bias resistance set to whatever the OEM ECU has .

[brokenboosted]

Sharing signals is perfectly ok if done correctly and has been done successfully many times.

Thank you! However after a few hours on here and about 3 hours on google i couldn't find anything about splitting/ tapping into a wave form signal(maybe im just using the wrong keywords). Would i simply solder my wire into the pip signal wire as if it were any other wire? Or do i need something to actually split it without effecting the wave form? As for the TPS gotcha and fr the IAT and CLT sensors im going to be running brand new gm style sensors with new wiring as i cant trust the trash stock sensors.

[PSIG]

Sharing signals is straightforward, and you only need to consider two things.

• Anything added to the signal (shared device) must have a high-impedance input. In other words, it cannot "suck" the signal away from the original device, or add anything to it. Most Speeduino inputs are high-impedance, but some are not.
• The Speeduino inputs must not alter the original signal, or it will affect the original device(s).

These two rules are actually two versions of the same thing. Do not alter the original signal. For example, the Speeduino IAT input has a bias resistor adding 5V to the sensor input. So does the original ECM. Using both bias resistors will significantly alter the signal for both devices. We can remove the bias resistor in Speeduino, so it can read the input signal without altering it.

Added circuits such as VR conditioner modules can add input issues. Some modules consume current (low-impedance), and others do not (high-impedance). If sharing signals, simply tap into the signal line and use a module with high impedance. The module does not need to be perfect, but simply not alter the signal in a way that makes it unusable for the purpose by either device.

If necessary, remove any module input capacitors or other components that could alter the basic signal. If altering the signal is unavoidable, a high-impedance circuit may be added in-line to provide a strong signal without altering the original -- but that's rare.

Likewise, we can use the existing OEM-powered signal such as TPS, with the OEM ECM powering the TPS sensor, and Speeduino only reading the output voltage. For this, the grounds of both devices must be identical so there is no voltage offset. I always power and ground Speeduino from the same points as the original devices in order to avoid any voltage offsets, ground loops, etc.

This is the same rule to avoid signal-offset issues with other "add-on" devices such as WBO2 controllers. Likewise, the reason we run sensor grounds to one ground terminal of Speeduino, and multiple power-ground wires separately, but to a single central ground point, such as the engine block. Have fun!

[Wlad]

i have a 90 f150 with a E4OD

4.9L L6 , 5.0L/302 V8 or 5.7L/351 V8 engine do you have on your truck ?

[Gearhed90]

Was there anymore progress on this project? I want to use Speeduino on my brothers 93 Bronco but don't know how to do it with the E4OD, what inputs does the transmission need from the ECM?

[PSIG]

I want to use Speeduino on my brothers 93 Bronco but don't know how to do it with the E4OD, what inputs does the transmission need from the ECM?

@Gearhed90 - please start your own new project thread for more info. For now (and as it relates to the original thread), the OP is using Speeduino in a "piggyback" mode, where the original ECM still controls everything it used-to. Speeduino only takes-over the fuel and ignition functions (and possibly others by option), so it still controls the transmission and other stuff like cruise control or AC as it did before.

The factory ECM will sense oddities that may throw codes or light the MIL/CEL dash light, but usually does not cause it to do anything functionally weird. Later models are integrated so tightly, that things can get weird. Still, it's an experiment with every installation, so don't be surprised if there is a side-effect. Usually no biggie, such as EGR fails to work properly when it sees odd AFRs and such. There are usually work-arounds or solutions if needed.