[GiannisPap]

Do you need to use the Speedy for ignition?

Could just use it for fuel only and allow OEM ignition control.

Won't need to tie into the crank/cam trigger then. Could just feed an injector pulse into the Speedy and set to distributor or whatever it is.

For 2 cylinder engine and piggyback fuel control and distributor decoder do i need the signal of 1 cylinder or 2???

[jonbill]

AIUI, "piggyback" is when the new ECU modifies signals in and out from the original ECU to add more fuel (etc). In which case the original ECU will fight with the new one.
What I did here is a parallel install, where the two ECUs see the same sensor signals, but only one of them is in control of the output.
In my case, the speeduino controlled fuel and the toyota ecu controlled spark and vvt and the gauges.

[Kurt]

Hello, sorry to bump this thread, but this seems like the best source of 1ZZ info!
I'm currently building a jumper harness to go to my UA4C so I don't have to directly splice my loom, and I've found Jonbill's wiring diagram/table very helpful as a start, but I'm just wondering if someone could clear up exactly which sensors should still be shared with the Toyota ECU please. I've attached what I have so far, but I'm just a bit unsure if I should bother to splice Crank/Cam VR and TPS etc.

Also not sure if this is the best place to ask questions about the UA4C (vB3c), but I don't see JP1 on the board? so I assume it will automatically be 5V out? Also I'm a bit confused about where (or if I should!) cut for the parallel install on JP14

[jonbill]

Hi, yes, I shared CLT, IAT, TPS, crank and cam sensors between Toyota and the Speeduino ECU.
I used the speeduino MAP for load - there was a convenient little spigot just the engine side of the throttle.
I don't know about the UA4C question I'm afraid.

[jonbill]

Actually, initially I used the built-in IAT, but that was located before the supercharger so didn't give a true measure of the temp. I later added another IAT at the elbow before the throttle (and after the supercharger)

[Simo5000]

I’ve gone on-board MAP sensor with a Speeduino 0.4.4C board and a GM IAT sensor. No MAF but will keep it plugged in for the time being. There is an option for Toyota CLT sensor in Tunerstudio which I’ve selected but i believe Bosch can be used, I’m close to firing up the car so will let you know. But all readings come back as expected without firing (turning over etc). But as Jon has said ( which I’ve followed) these are shared by Speeduino and OEM ecu (to keep it happy) but Speeduino controlling firing etc.

Jonbills wiring diagram has all you need to know, use the sequential firing.

Also I’m using a breakout board but have spliced the loom. I may do a pnp later.

[Kurt]

Sweet, thanks both

[Simo5000]

Hi Jonbill,

I’m having an issue with the coolant temp sensor.

On warm up it bottoms out at 67degc (showing on the Speeduino and OEM dash). If i disconnect the spending, the OEM dash shows the correct running temp.

Any ideas what could be the issue? I connected the MAF to too see if there’s any issue there but nothing.

[jonbill]

Did you remove the clt and iat bias resistors from the speeduino board?