Technical MK1 Turbo IE : Fails to start, no injection...

[soufiane83]

Hello everybody,

First, let me introduce, I'm French (so I apologize for my "poor" english) and bought a Uno Turbo IE mk1 a couple of years ago...

When I bought it, it already did not start. I've changed the relay for the fuel pump, it was too old and burnt. That's all I've done.

Since, I've tried many things, but it still doesn't start.

I can tell you that the ignition is working well, because when I feed the engine with fuel in the inlet manifold, it's starting well until there is no more fuel left...

So could you please help me to find this injection problem, due to somekind of sensor or wiring, I don't know.

I thank you all for helping me.

 

[soufiane83]

I've forgotten to tell you something :

The fuel pump is now ok, and the fuel comes to the injectors, but they don't "open".

I did some measurements, and I know that the four injectors are fed with a good fuel pressure and that +12 V power is on too...

It seems that the Injection ECU doesn't open them... Why ?

 

[Uno driver]

Check crank sensor, if I remember correctly it's somewhere around flywheel. Fuses are OK?

 

[oldskoolmk1unoturbo]

clean up the injector earth on the top of the engine, mine was corroded and the car wouldnt start

 

[soufiane83]

Hi ! I'm back...

The fuses are OK, and I've check the two grounds, the first on top of the engine, and the second on the gearbox...

For the crankshaft sensor, or the other above the flywheel, I think that they are good, because the ignition is OK.

Thank you for your help

 

[alexGS]

If the wiring to the injectors is not shorted-out (quite possible given its location across the hot engine parts), and the ECU doesn't ground the injectors at all with the engine cranking (check for a voltage across an injector), and you have tried another replacement fuel pump relay, and you have checked that the airflow meter has a varying resistance when you move its flap...

...then I'd say the ECU is faulty. This is the ECU inside the car under the dashboard (not the ignition ECU behind the engine).

I think you are correct in your diagnosis of the crank angle/flywheel sensors being OK - because they are for the ignition and not the injection system. The injection system has a connection from the ignition coil to the 'fuel pump' relay (the special tall relay, near the battery, that actually powers the injection system as well as the fuel pump). The connection from the ignition coil is how the special relay senses the engine speed. Uno Driver was still right to suggest the crank angle sensor though, because obviously if there's no ignition, there's no signal to the injection system either.

I suggest that you get a Haynes manual if you haven't already - it gives a useful pin-out of the ECU connector so you can check the wiring from there to the injectors. It shows the fuel pump/system relay connections. It also gives resistance values for the other components - very useful for basic checks with a multimeter.

I am impressed by your English and hope you can understand mine OK

-Alex

 

[soufiane83]

Hello everybody !

I've done some electrical tests. The four injectors are well powered, but they don't get grounded by the ECU...

I don't really think that my ECU is faulty, because I've tried another one, and still no injection.

Iv'e read a thread where the fuel pump doesn't self prime, I've got the same problem. My fuel pump is going fine, but doesn't self prime either. So I'm thinking about some kind of electrical problem that make the ECU not functionnal.

Thank you for your help and any good ideas... :idea:

 

[timmyr]

Check so the cables on the spark distributor are right, mine wouldn't start either before but i changed the cables and it started. You can also try to put ground between the engine and body.

 

[soufiane83]

In fact the ignition is working fine. I've got good sparks

But the problem is an injection one... But I'll try to connect the ground from the body to the engine.

Thank you...

 

[soufiane83]

Hello UT drivers !

I'm back, with some news and questions... I've bought a tester (called Breakit, it's an old bluepoint tool), made for testing LE/LE2 jetronic systems, as fitted on our Dears Unos !!!

Well, doing the tests, I've seen that my ECU doesn't get the coil signal when cranking the engine, which still doesn't run...

In order to run it, I fed the engine with some fuel. :slayer:
It ran for a few moment, still the same problem when cranking my engine, but then I got a coil signal when the fuel made my engine alive !

To resume, with the help of this little tester, I'm sure that my injectors are out (because the tester showed an injector signal). But I don't really know if my coil is out too ? Did you have the same problem ?

Thank you all for your good help :worship:

See U

 

[SteveNZ]

From what you have said, your problem is either;

No power or poor earth to the ecu
No signal from the ignition coil
Faulty ecu

It sounds like an ecu earth fault. Check the ecu earth. i.e. use the positive terminal of the multimeter and look for any voltage. while your at it check the for any voltage on the chassis (checks main earth).

Could also be something very simple like the spade terminal on the coil not connecting