I know the previous owner had a bit of electrical work done, but I also know he was a little bit dumb. For example, there's a taillight kill switch wired into the dashboard so you can run from the cops...? that's what he told me anyways.

There's also an alarm installed. I don't...think...this is related.



Lower right wire on the left plug is cut, run into this blue chip thing, and then run back to the harness. There is also a ground coming out of the blue thing.

Which wire is that? Is this some sort of high-tech IAT resistor dealie? I don't want to pull it until I figure out what it is.

 

you can go to the FAQ and factory service manual then look at the wiring daigram and see what that wire runs to.

 

If those wires are black they're grounds.

 

That small plug..............that is pin 3B on the bottom row, far right that the wire is coming out of.

3B is the START signal the ECU sees when the key is put to START. It only has 12v on that wire when the key is held to START.

I can't tell what is going on from there. Unwrap the BLUE tape and take a picture of what is under there. Even if I see the device I probably can't tell what it does in life.

It's a possibility that this is a device that does not let the ECU see the START signal when the engine temperature is above a certain degree(s). If that is the case it means to me he had hot starting problems and this device is used limit the amount of fuel delivered during the START cycle. It would ONLY effect starting and nothing else.

That's my guess.

EDIT: It certainly is the Blue/Black start signal wire to the ECU, but my above GUESS won't hold much water since there would have to be another wire going to the device from a signal that gives water temperature. So, who knows. ONly the Shadow knows.

 

Hmmm...is it possible that's for the alarm? If the alarm is going off, it disables the start? Or maybe if the car is started, it disables the alarm? I know I can't arm the alarm with the car running.

 

i believe it COULD be from an SAFC. I don't remember the exact name for it but you have to split a wire in a very similar fashion in order to properly install the SAFC.


YUP!!!!! I see a purple wire taped off too ( IIRC it the injector signal)!!!!! If you take more pics I can go home and check my notebook for BETTER details but I'm leaning towards an Apex-i piggyback.

 

The BLUE/BLACK wire at pin 3B is the START signal to the ECU and only sees voltage during start. Yep.Could be ALARM related especially if under that BLUE tape there is nothing but a bunch of twisted wires.

 

Lmao, thanks...I was installing an SAFC when I noticed this. You cut the MAF sensor wire.

Purple wire is knock (on the SAFC side anyways), that might be what you're seeing



There's a tiny chip also under there with some componants on it. You can kinda see it in the picture.

Maybe it grounds the start wire if the alarm is going off so you can't start the car? This is bugging me!

 

the better way to do that would just be to cut the ground on the starter relay, cause the car may still start with this change under certain conditions.

 

This is a device to help with the hot start issue, i had one on my T2. I've only seen it on one other car befor you.

https://www.rx7club.com/showthread.p...ght=augiedogie

 

Augiedogie seems to have seen the same thing and it makes sense.

How that device would work is anybodys guess.

It will NOT gnd the Start signal to the ECU because if you gnd the blue/black wire you would pop a fuse.

I've mades something similar (not real similar) in the past. First you have to know that there is a START MAP in the ECU that does NOT use the afm signal at all. It uses water thermo temperature, rpm under 500 and that 12v start signal on pin 3B. Problem with this, is that the START MAP may inject too much fuel for a given engine, causing flood during hot engine starts. So I made a device to kill that Start signal on pin 3B when the water temp was over something like 120*. When that was done the Start Map is NOT used during starting and now the afm signal for fuel IS used during start.

Trust me, the amount of time the injectors is open during start using the afm compared to the Start Map is much, much lower and will overcome a hot start problem.

The chip in the picture does not seem to intercept the water thermo sensor signal (green/white wire) so I've not a clue how that thing works. Just rambling. Gone.

 

Car doesn't start when the alarm is going off.

Maybe I'll cut the two wires to the chip, splice them to the chip, and then try to start the car with the alarm on.

I don't see how it would be a hot start issue if it doesn't see water temp...

 

At the RED splices, there is a black/blue wire at each splice that used to be one wire. And it went to pin 3B. So I know what they are.

I know what the white and grey wires are, just aftermarket wire to make a connection.

The one wire I can't figure is what looks like a BLACK wire coming off the blue wrappiing and going to, I think the wire bundle? Just where is that BLACK wire going? Is it really just a pure black or another color?

I don't see it being an alarm device myself. But I don't know what the *black* wire is or goes.

 

the unit splices between start wire with the remaining wire going to ground. I have know idea how it works BUT. When the capaciter (sp) broke on my little chip i experimented with it. I found that with the ground wire cut the car would start while hot, but not cold and vice versa (that may be backwards though)

Right now my hot start problem is solved by a switch that cuts the start wire when hot that changes the injector pulse width so i can start.

If you dont believe me about it being a hot start assist, disconect the ground wire, and you will see what i mean.