Last week my Fiat 500c started running rough. The diagnostic thing said it needed a new ignition coil.
So today a friend helped me...but it turned out that Auto Zone gave me the wrong part
The car was starting fine up till then but when we put back the old coil the car wouldn't start. It turns over but refuses to start.
Battery is fine, battery connections ok.
Any idea WTF is going on???

Seagoddess54 said:

Last week my Fiat 500c started running rough. The diagnostic thing said it needed a new ignition coil.

The car was starting fine up till then but when we put back the old coil the car wouldn't start. It turns over but refuses to start.
Battery is fine, battery connections ok.
Any idea WTF is going on???

Click to expand...

Hi. And welcome.

What error code did you see?

What engine...1.2 or the Twinair??


Charlie

varesecrazy said:

Hi. And welcome.

What error code did you see?

What engine...1.2 or the Twinair??


Charlie

Click to expand...

Am I right in thinking most US cars are 1.4? could be wrong though.

PO 301 Cylinder 1 misfire.

1.2

Seagoddess54 said:

PO 301 Cylinder 1 misfire.

1.2

Click to expand...

Ok so I was wrong, you learn everyday?

Oh sorry you're right. 1.4

Hi again.

Ok..

Trying to figure out what you will have disturbed.

Probably a 'coil pack'..

This supplies the sparks..

The traditional units are a pair..
Supplying 2 x cylinders each.

So If you only swapped 1 pack..it should JUST attempt to run.

Swapping the HT leads:cables..

So they are now going to the WRONG cylinder... that may be it..


Let us know.. what the incorrect part was..

A picture.. or
Url link.. would be hrlpful.

They gave me the wrong coil. The round one is the correct part.

Ok. They are 'stick coils'

One per spark plug..

Are the cables long enough that you could couple up to a different cylinder??

If you tried to start the car using the wrong coil then you could have blown a fuse.

Have a look at the fuses (there will be a box on, or near, the battery) to see if you can spot a blown one. Replace it with an exactly the same rating/colour new fuse.

Check whether or not there is a spark at each cylinder. If you have a spare spark plug attach one of the coil packs to it and place the plug so the electrode is sitting on a metal part of the engine. All the other spark plugs (*including the one whose coil you have removed*) should be properly screwed into position and the other three coils should be attached to their correct plug.

Now try to start the car. You should see a spark at the spark plug on top of the engine. It's easier to see it if the car is inside or it's a little dark. If you have a spark then that coil is good. Check the other coils in exactly the same way, one at a time.

When you're propping the spare spark plug on top of the engine, don't touch any metal part of it, or the coil. Wear rubber gloves for good measure. You won't *necessarily* die from the electic shock but you'll glow in the dark for a week, which might not be a good look.

If you have no sparks on any plug then that's a different problem to if you have sparks on some cylinders and not others. I suspect everything is "dead" so that might be a fuse problem (if you didn't check them by now) or an immobilisor issue.

If you have sparks then the problem may be fuel... but that's one for later.


Ralf S.

Hoping Seagoddess54
Figures out the issue. And lets us know where the problem was.

Charlie

Yes, I figured it out. It was a fuse...PHEW! At first the engine light stayed on but after driving it a bit it went off and now it's running smooth again.

Seagoddess54 said:

Yes, I figured it out. It was a fuse...PHEW! At first the engine light stayed on but after driving it a bit it went off and now it's running smooth again.

Click to expand...

Good news !!

Could you please explain - what fuse ?

Do think it was related to the original issue.. or a symptom of swapping parts.

Useful to know.

Thanks. Charlie

Ralf S. said:

If you tried to start the car using the wrong coil then you could have blown a fuse.

Have a look at the fuses (there will be a box on, or near, the battery)

If you have no sparks on any plug then that's a different problem to if you have sparks on some cylinders and not others. I suspect everything is "dead" so that might be a fuse problem (if you didn't check them by now) or an immobilisor issue.

If you have sparks then the problem may be fuel... but that's one for later.
Ralf S.

Click to expand...

Great call there

Not something I think of.. having not changed fuses very often
(Not since going'Italian'..@25 years ago)