Idling Rate and Stalling?

[18Fiatsandcounting]

Yes, it definitely could be an issue with the AFM or its connections. It's been decades since I had a fuel injection Fiat, so I won't be of much help here. Sorry!

-Bryan

[evrenosogullari]

So replacing the Air Filter Meter didn't work.

Current symptoms:
- After a day of driving, the car becomes unmanageable. Shuts off every 500ft if going less than 20mph
- Burning smell behind the steering wheel under dash (could be in my head)
- When idling, the engine seems to pulsate, it's subtle....
- Car is running a tiny bit hotter than usual in traffic

Thinking it's either:
- An electrical issue near the ignition
- A faulty spark plug
- No idea

Going to keep investigating.

[18Fiatsandcounting]

Did your mechanic ever get a chance to take a look at it?

From all that you have described, it sounds like you have a large air leak into the intake somewhere, which will cause the engine to run lean. This will cause:

Poor idling and even stalling as you describe,
The engine will run hot which could be the cause of the smell behind the dash,
Running lean can also cause an engine to pulsate, or "hunt".
As mentioned, running too lean will cause the engine to run slightly hotter than normal.

The good news is that running lean should slightly increase your gas mileage!

A good mechanic should be able to put a vacuum gauge on the intake, and while every engine is somewhat different, he can probably pretty quickly tell if it appears you have a vacuum leak. Note that not all vacuum leaks are constant: Some appear and disappear as various emissions control systems turn on and off.

-Bryan

[redcars]

For the burning smell check the electrical connection on the wires from the ignition switch. If it is really bad the outside will be brown. If not unplug it and remove the wires from both ends, one at a time so as not to get them mixed up, and clean them. Also squeeze the female ends tighter. If you have a burnt one you may have to replace some wire and the ends.

[evrenosogullari]

Currently at the mechanic in Long Island.

He says he left the car running for a long time to try to replicate the issue and noticed that the lights got dim at one point.

He's recommending replacing the alternator. $650 for the alternator and labor (says the new alternator costs 4-something).

I can see how an intermittent power shortage could cause the tachometer and the car to short out from time to time. If not that, he's going to check the wiring, and I can ask him to test for a vacuum leak.

[18Fiatsandcounting]

He's recommending replacing the alternator. $650 for the alternator and labor (says the new alternator costs 4-something).

That's pretty steep for an alternator, but I also understand the markup on parts at shops can be severe (2 or 3 times their cost). A quality alternator can be had for less than $200, even as low as $100 for a cheap one from generic auto parts stores, and it takes about 30 minutes to replace. An hour at most.

Just my opinion of course, but I'd start with checking for vacuum leaks before I'd replace the alternator. You don't have any of the classic signs of alternator issues such as battery going dead, lights flickering, belt squealing, etc. There is also specific equipment to test the alternator itself, which would be the best route rather than replacing it "because that's what it might be." Some auto parts stores will test your alternator for free, as well as places like Walmart service centers. Of course, they'll try and sell you an alternator (or battery, or voltage regulator) when they're done, of course!

-Bryan

[maxm50]

Yowza. That’s expensive for an alternator replacement. But then again, you’ll find that most of us on this board do all our own maintenance.

I don’t think you should blindly replace it without confirming it’s the cause. Leave it running with a voltmeter hooked up to watch the alternator output, and see if the voltage drops or increase at the same time that your symptoms pop up. I had a very similar problem with an intermittent rough idle, and I found that the voltage jumped up at the same time the rough idle would start. Then after a few seconds it would stop sputtering and smooth out, and sure enough the voltage stabilized to normal levels also. This was caused by a bad voltage regulator, which I replaced in about 10min with nothing more than a flathead screwdriver, without removing the alternator. Super easy. The regulator is also available at many local stores or from online vendors.

Long winded way of saying: don’t just replace an alternator because you “think” it’s bad. It’s an easy part to test and confirm if it’s good or bad.

And again- just replace all the vacuum lines. They are decades old and if they aren’t leaking now, they will be soon. They are dirt cheap and fast to do.

Is this mechanic a Fiat specialist? Sounds like you’re in for a long list of expensive repair bills with this guy, if he’s not really taking a methodical approach and charging rates like that...

[Nut124]

I would wait on the alternatror.

I'm with Bryan on this. A vacuum leak can cause all the trouble you have reported. Poor idle, unstable idle, stalling, running hot.

I would use all the tricks in the book to look for and locate the vacuum leak when the engine is exhibiting these symptoms. Starting fluid spray in a safe outdoor situation.

[evrenosogullari]

Well he's already installing the alternator today... because he noticed the lights went dim after running it for a while. We'll see. He did once manage to fix an issue with the ignition starter pretty quickly...

If not, I'll have to start going to another mechanic I found in the Bronx who does old Italian cars and had said some things on the phone that was much more in line with what people are saying here... and perhaps won't take me around the block with markups....

Will see!

[evrenosogullari]

Hi All
I've taken this car to a new mechanic since the car has gone off and won't start after replacing the alternator (seems that wasn't the issue afterall). The mechanic is asking for me to order a new ignition starter because the old one shorted out before he can even check for an air leak.

He's also asking if I have a wiring schematic.... any idea where to get that from?

Thanks!

[tima01864]

Mirafiori.com may have your schematics, Midwest Bayless does have literature as well

[aj81spider]

Mirafiori has them. I have a .pdf (probably from Mirafiori!). If you're stuck PM me your email address and I'll send it over.

[18Fiatsandcounting]

The mechanic is asking for me to order a new ignition starter because the old one shorted out...

It looks like you have an answer for the wiring diagram question, but on the question above: Does he mean the starter motor? Or the solenoid for the starter motor (engages the starter motor when you turn the key), or the ignition switch?

-Bryan

[evrenosogullari]

Great, I think I found a PDF!

He was saying simply the ignition starter has gone bad (just the metal cylinder). Because electricity is going into it, but not coming out. It's odd, because I had supposedly had the ignition starter replaced like 4 months ago

[18Fiatsandcounting]

I don't recognize the term "ignition starter" (could be a regional thing), but what I think you're describing is the starter solenoid. Yes, these do go bad from time to time, but it's also common for one or more of the wires connected to them to come loose, and then the car doesn't start. It's fairly easy to test whether the solenoid itself is bad or it's not getting power from the ignition switch for some reason, and your mechanic should be able to do this.

-Bryan