Speedworks

Hy Guys,


I'm nearly at the end of my knowledge here.

I rebuilt my engine and in the process I disassembled the front end incl. wiring for a repaint and rework.

In the meantime the engine is back in and so are all the wirings.
I ended up connecting everything together and installing my PFC and Commander from my previous car (both 93).

Weird thing is that everything on the car works, clicking noises went turning the key, starter engine is working fine, dash lights are functional.

Just the tunnel light (overheated cat) is lighting up. So that might refer to failure codes...

The ECU is getting current but isn't putting out much. The fuel pump works (took it out for a battery test which was OK) but once it's in the tank I can not hear the whine when putting the key in preignition.

My PFC ECU could be toast but then again, it worked fine for 2 years, was taken out and installed correctly again. It' was sitting on my shelve all the time.

The commander isn't working either.


I have tested everything 4-5 times and don't know where to go next. I don't know if this is OK but the main wiring going to the alternator has a constant 12 volts on it even when the key is out of the contact...

I'm more of a mechanical guy instead of electric so any help would be greatly appreciated.

Many thanks
Neal

CantGoStraight

Yep the alternator wire has constant 12v on it. That's one reason it's so important to unhook the battery when working on the car (very easy to hit with a wrench ) when doing even minor maint.

Speedworks

I noticed that

Is there any other way I could check wether my PFC ECU is gone?
For example, will the spark plugs still fire when the ECU is dead?

My feeling is the ECu, but I have no way of testing it.

my OEM ECU was sold months ago and FD's are rare here so picking up another one for a quick test is not so obvious.

thx

bryant

Troubleshooting:
After you have checked your wiring, you can start your car. If you car don't start, check your wiring
again. After you performed all the inspections but your car still don't start, try to follow this guide:
Check for RPM at crank. Use Datalogit and check if the ECU sees the right signal from CAS at
crank. Datalogit should read about 250 RPM at crank. If Datalogit don't display anything, you
should check your CAS wiring. Pay attention to the connector between the CAS and your wiring
loom. Remember, on the CAS side, the red and the green wires are signal wires, where as the two
black wires are ground. On the harness side, the colour will change! Now we need to look at the
black white wire (the should join the red, green on the CAS wiring) and not for the red green, at the
red green on the loom side is connected to the ground (the two black wires on the CAS).
Check for right installation of FD igniter. Remove your leading spark- lead and connect it to spark
plug (not the installed one). Crank the car and take the spark to chassis and look for spark. If you
have no spark, check your igniter installation. Perform same check with both trailing sparks.
Fuel pump: Well, the best way is to listen for the fuel pump noise. If you can not hear anything,
check your wiring and your new relay.
After you have done the installation, you should have something like this:
ECU installed....!


from this book http://www.rotary-imports.de/space/PFC_install_FC.pdf

Speedworks

Thanks for that



What I find strange is that my commander does not give any sign of life while all the other electronics seem to work fine.

My PFC was in my previous car for 2 years and was taken out without any problems. Put it back in the box as long as I didn't use it and now just reconnected it.

I'll start looking for the problems as you mention and give it a try starting the car.

If that works I'll be on the ECU to check if the output signals are working (especially the OMP related ones).

The fuel pump doesn't work for sure because the hoses were dry as hell on the inside.

The white connector on the fuelpump was reading around 5 volts and 12 volts for the fuel sensor (to see how much gas you have left), but nothing on the other 2 for the fuel pump.

I checked the 20A fuel pump fuse, which was OK. I even switched it with another one. The wiring at the fuse was reading 12V so that one is doing fine.
Somewhere in between things are going wrong.

Busted7

If you found out the hard way about the power on the alternater you may have blowen a fuse!

Speedworks

I checked all the fuse but so far every single one of them is OK.

What is most enoying is that I can't try to start then engine as my fuel pump is not working.No fuel, no start obviously.


Is there any way I can reset the PFC ECU without it being in the car?

The link posted above also states that the PFC ECU pinning has a diagnostic pin. Can I do something with that?

bryant

it says in that install that the ecu doesnt run the fuel pump i would say if you grounded out you need to check the yellow relay.

Speedworks

ok so the the fuel pump should run regardless of the ECU... I need to check that..

THX

Speedworks

Update....


Done some wire testing and this is what I got.

1. tested fuel pump relais. Works fine.

2. fuel pump relais needs to make connection between blue/red wire and white/red wire. Red/white goes to fuse box and on to fuel pump.
Red/blue wire has no current on it at any stage of ignition, but does read ground... which is odd

3. made bypass from battery to red/white wire makes the fuel pump run -> good

4. red/blue wire goes from fuel relais to relais box at drivers side suspension strut.
ignition OFF-> no current on either wire on the Circuit Relais.
Ignition ON -> current on all wires BUT red/blue wire. Other wires are fat blue wire, thin black/white, thin black/blue.

The red/blue wire should read current and be the constant feed to the fuel relais, so when it switches at ignition, the fuel pump starts.


CAn somebody point out what the circuit relais should read, and where the wirings of the circuit relais run to?

Thx

Busted7

Do you have a fd wireing diagram? If not you can go to RotaryHeads.com and down load a pdf file.