Technical No spark on 1.1 SPI, twin coil Marelli

[olNick]

No spark on 1.1 SPI Trekking, circa2000. Twin coil Marelli

Hi,

This month the Panda has refused to start on 3 ocassions, cranks but no spark.

First time, month ago, was outside a Fiat garage, and the mech said its the crank sensor.
Went bought one, and before replacing, the car started.
Replace the crank sensor anyway.

NOTE for others: I read somewhere that if the CPS is bad, injector will not fire either

Second time, couple of weeks later, same thing, but was downhill and car started when I popped it in gear.Strange

Third, and last time (Thursday), same thing, no spark. In a field and could not try and push.

Towed it home yesterday, and for kicks popped in gear and it started, ran as normal. Drove home.

Car started normal this morning. Have it facing downhill for when I get out of work just in case.

Only abnormal symptom noticed;
2 times last ten days or so is had to try the ignition switch back-forth 2-3 times before it cranked and started normally.
Also feel the car used to start easier, 1/2 rev and away we go. Now it cranks several revs/half-one second before firing

Checked coils secondary resistance, 7.5K ok to spec,
Injector was firing, but no spark.

No resistance (short circuit) when ohming out battery neg and ground points on car.
Regardless, will clean the grounds and add another strap this afternoon.

Any ideas? Switch? Any relays to check?
Does the ECU or the switch gives 12V to the coils?

I do not have an 1.1 SPI wiring diagram. Anyone have one? Think the Sei had the same SPI


tx,
nick

 

[blu73]

you are correct that a failed crank sensor stops both spark and injector firing..

the ecu fires the coils through a relay, its sometimes called the twin relay by some. It has the fuel pump relay and relays firing each coil. I don't think it would be that but you can check it, usually its a white casing but i have seen green ones and brown ones, slightly bigger than a matchbox - can't remember location in engine bay though.

the needing to turn key multiple times to get it to start turning over seems like it could be the source of the issue perhaps without looking at a wiring diagram.. could just be a faulty ignition barrel.

I would also check the engine harness earth. The panda has a battery negative to body then to gearbox as earths but there is a earth for the engine harness which from memory bolts to back of the engine block - not had a panda for a while and can't remember exactly, but its a group of all black wires to a ring terminal thats bolted somewhere on the block, pretty sure its on the rear of the block though. Check that.

Wiring diagrams are in back of the haynes, so buy one or try find one to download online, mega handy for stuff like this. You can use the diagram to properly test the ignition barrel is working properly with a multimeter.