Coil resistance on 1.6 engine

[stuart]

I've been checking the resistance measurement on the ignition coil thingy on my 1.6. Haynes gives readings of 0.6 ohm primary and about 9000 ohms secondary. I get a (good) reading on the low tension side for both halves of the coil but the high voltage side reads open circuit on all four terminals. I'm measuring it with a decent digital meter. Car is an old '96 with 90k.

Any experience of these coils failing?

I'm checking over the ignition and injection sensors because the car runs rough at low revs and can still be a bit tricky to start when cold (fine at high revs). It's the only problem I found so far.

If the coil is shot, where is the best place to get a new one - looks expensive (

Stuart

 

[Anonymous]

Where are you measuring the resistance? You can't measure it between the coil output and the engine, its between pairs of coil outputs.

Have you tried new plugs and leads? If you had a shot coil it would not run at all.

 

[stuart]

Re: Re: Coil resistance on 1.6 engine

Yes, I was checking between the coil outputs and the engine.

Just been out and checked again. I get the correct resistance between each pair of outputs - that's saved me a few bob.

Spark plugs are brand new and the HT leads check fine with the meter. I guess I'm back to checking the injection sensors etc.

Stuart

 

[Anonymous]

Re: Re: Re: Coil resistance on 1.6 engine

Checked the idle valve?

What sort of RPM range does it run badly over?

 

[stuart]

Re: Re: Re: Re: Coil resistance on 1.6 engine

Yeah, the first thing suggested on this list was the idle valve. It was covered in black goo which I cleaned off but it didn't fix it completely. I can get it started now (even cold) as long as I hold the accelerator pedal down slightly when I turn the key and rev it slightly for a while.

Problem is it still hesitates and jerks a bit below about 2000revs, especially on light throttle. Over that it seems fine.

My next plan was to check out the manifold, throttle body and breather pipes in case they are choked with the same goo, then check out the other sensors from the injection. I did think of taking it to Fiat for a diagnostic but I'm not sure they would find the problem.

Stuart

 

[Anonymous]

Re: Re: Re: Re: Re: Coil resistance on 1.6 engine

If there is no warning light then the diagnostic will say nothing. When it comes to Fiat mechanics, no error code means nothing wrong with your car.