Help with FTO wiring problem

[spoid]

Hi Guys , hope I might be able to get some advice etc with an FTO engine problem from hell.

Several years ago we took a 96 manual FTO GPX to a place that was said to specialise in Mitsu's. Will try and cut this long long story as short as possible.
We took it there because after hard acceleration, the engine check light came on and it barely idled (rough as guts before stalling). This repair bunch claimed the whole engine has gone to Sh*t and it ended up costing us over 11 grand all up.
They claimed that they couldnt get all 6 cyls fireing so had to put in an extra ecu to handle most of the old Ecu's duties. yeah I know, sounds like A grade BS doesn't it but we didnt see that we had much choice at the time.

Anyways, it has been running OK for the past couple of years until today when it lost power and stalled... The starter motor turned the engine over just fine but it would not start... After having a good look around the engine we noticed that the "repairers" had jumpered a plug in the wiring harness and that the jumper had half fallen out... upon lifting it up to take a look, it fell out completely and we have
no idea where it goes back. Downloaded the FTO circuit diagram manuals and found the connector which originally connected to the Igntion Falure sensor but seems to have been bypassed, I assume it is no longer needed with the new ECU but must have to be Bypassed to keep the original ECU from chucking a fit???

The question is. Which two pins on the 4 pin Ignition Failure Sensor would they have bridged?? Any suggestions would be most helpful.

Attached is the circuit diagram of the IFS and its pinout.

Have been trying to understand how the IFS works, and how it connects to be able to monitor the Coils. In the second pic I have put an arrow pointing to a wire, AM I right in thinking this must be supplying a Positive Voltage to the coils whenever the ignition is ON ??

I'd really be grateful if anyone can give suggestions etc.. we would try contacting the place that did the modifications if it wasn't a weekend and we weren't 200ks away from there shop AND that I would be willing to bet that they wouldnt remember the horrible bodge job that they did anyway

[spoid]

Just had to make a correction to what I typed above..

They didnt bridge the Ingnition Failure Sensor, They Bridge the CONNECTOR that originally went to the IFS. (the connector was no longer plugged into the IFS, instead was a wire bridging two of the four pins in the plug)

[dstocks]

Wow, they took you for a ride didnt they. 2 years ago, an engine replacement should have cost you 4K tops. 11 is just crazy. You may end up having to try the combinations. Most likely worst youd do is a fuse.

[PHIL069]

I would say if they have bridged 2 wires to keep the ECU happy...

Pin 1 = Earth
Pin 2 = ECU
Pin 3 = Coils (Earth)
Pin 4 = Positive

I believe that the IFS would get power from PIN 4 and when the coils are active (pulsing on/off) it gets earth from pin 3.
When it gets a closed circuit (Pin 4 + 3) from recieving earth from the coils it then closes the circuit inbetween pins 1 + 2.
When 1 + 2 are closed the ECU gets a closed circiut and is reading that ignition is present.
Now i reckon the circuit from ECU to ground via pin 1 + 2 would be a pulsing circuit (on/off/on/off/on etc) as the coils fire, the rate of this pulse allows the engine speed to be detected and metered.

In saying that if you bridge 1 + 2 the ECU will get a constant closed circuit.
If you bridge 2 + 3 the ECU will get a pulsing circuit from the coils, but I'm unsure if bypassing the Constant pulse generation circuit within the IFS is a good thing.
The "CPGC" would keep the pulsing and voltage at a constant speed varying beat.

That's all I have, good luck

[spoid]

Hi Guys.

Thanks for your suggestions, certainly helped us solve the problem.

Turns out the old ecu doesnt need the IFS Pulses anymore, and they had jumpered pin 3 ( + to the coils) and pin 4 ( + from the ignition key). I wonder if pin 3 supplies +voltage to the coils in all fto engines. From the circuit diagram it seems that it does. Originally thought the Ignition Failure Sensor monitored the coils and informed the ECU that they are ok or not, but it seems from what I can work out from the circuit diagram all it does is inform (by sending pulses) the ECU that there is + voltage from the ignition switch. Do you guys agree?


Now if only they had used a few cents worth of electrical tape , the damn jumper wire would never have fallen half out .. especially considering how much they had (over)charged us to rebuild the engine in the first place !!. oh well you live and learn. Just so glad to have the car running again without another massive repair bill.

I hope other people have had better experiences with this repair mob than we have.


All the best guys

Brad