Trying Bosch ECUs

[Bali]

Hi!

How dangerous to try a possible wrong ECU?
My car is a 2000 IE and there is another 2000 IE which doesn`t start.
The owner thinks there is trouble with the ECU (Bosch) and he would like to try it on my Beta and then try my working ECU on his car.
Can these cause trouble in my car and in my ECU?
(I`m thinking about buying that car.)

Thanks in advance,

Bali

[A1.6HPE]

Hello Bali,
The ECUs are very reliable. If it is faulty the cause is probably a wiring problem in the car so do not connect your good ECU into the other car. However it should be safe enough to try the suspect ecu in your car.
However this would be your own decision and at your own risk!!
The injection system is quite simple - can you hear the pump running when the starter is turning? (pump is fitted on the rear suspension crossbeam). Can you hear the injectors clicking as the engine turns over?
The most likely area for a problem is the "Kombi-Relay" which is mounted on the right hand front suspension turret. The connections corrode. I think that there is an in-line fuse holder - the fuse contacts may have corroded. The unit should click like a relay when the ignition is turned on and off.
A common failure is the temperature sensor which is fitted in the water pipe above the engine. Although the engine would start if that was faulty - just would not run when hot.

It should be safe to try the Kombi-Relay in your car.

As I said above - do not put your good units in the faulty car unless you are sure that you know what you are doing.

Good luck. Leo

[Will]

Exactly. that Bosch dual relay is most often the culprit, just as he said.
Good point on swapping the ECU's , no need to cook a good one!

Another point is to check the grounds to the cam box end plate.There's a wiring diagram of the way the harness is supposed to be set up in the photos section, "will holdings albums/fuel injection" and there's a troubleshooting guide to the whole nasty mess (and a darn good one) over on mirafiori.com

If the injector leads are not shorted and the other wiring is intact, THEN you can go ahead and swap the ECU's.
I think the ECU would probably need a HT shunt to blow it, they are pretty robust and could probably handle a minor shock at 12v. I've welded on cars with them and shorted the battery on a car with one with no ill effects to the ECU. But better safe than sorry!

-Will

[Bali]

Thank you for the good advices!
I haven`t seen the car yet but I`m going to check these areas first (with the given drawing) before we would swap the ECUs.
I hope it will be a simple problem with the contacts too, because once my 2.0 IE didn`t start for about 2 weeks and at the and it was the fuse-box at the mentioned relay...

Thanks,

Bali