Idling Rate and Stalling?

[evrenosogullari]

Hi All!

I've had my 80' Fiat fuel injection since March. Excuse my ignorance....

This weekend I took the Fiat from Brooklyn to Callicoon NY (~130 mi. distance). Was otherwise fine, but on the way I stalled out in the Holland Tunnel, fully stopping all traffic for about 20 minutes. I turned the Idling Screw a little so that it runs louder. I was able to drive without any problems but with it idling louder and the RPM always higher than usual (hovers around 4000 when driving at 70mph). Even with the idle turned up, it stalled once or twice briefly on the highway on the way home, which is a bit stressful.

Do I just need to turn it up higher? or is there a deeper issue (some kind of leak?).

[evrenosogullari]

Sorry. TMI. Basically I need to idle around 2500 to avoid the possibility of stalling out.

Is there a checklist or something people use to know why it might not be getting enough fuel / stalling out at awkward times?

[SteinOnkel]

First and foremost, check for vacuum leaks. What you're describing is a pretty classic symptom of unmetered air entering the engine.

Also, the Fiat Twincam is a wonderful engine. It can idle silky smooth all the way down to 400 rpm without stalling.

[18Fiatsandcounting]

Hi John, welcome, a question and a comment:

Question: Is the car stalling out when you're just driving along, or only when you put in the clutch (or put it in neutral) and the engine speed drops to idle? If the former, then it's not an idle issue. If the latter, then SteinOnkel's suggestion to look for a vacuum leak is the first place to start.

Comment: The Fiat tachometer reads from 0 to 80 or 0 to 90 depending on model year, but if you look at the very bottom of the dial, you'll see "X100". So, the engine speed (rpm) is 100 times the dial reading. So, when you're cruising merrily along at 70 mph, the tach will read 40 but this is actually 4000 rpm on the engine, which is about right for 70 mph in 5th gear.

-Bryan

[evrenosogullari]

To your question 18Fiatsandcounting, it only stalled out a few times as I was coasting along up to a red light or pulling out of being stopped in traffic (it's an automatic).

Now, it's not stalling anymore (for the past couple days), since I've turned up the idle a tiny bit. But now it seems to be running hot..... the needle comes right up to the red line, the fan comes on, and it dips down a little but pretty much stays way up there. Hasn't hit the red, but stays way up there in traffic.

Causes for concern?

May just bring it around to my local mechanic tomorrow to see if he has any idea why it's running hot.... I topped up with coolant just last week. Will check the coolant again and, to SteinOnkel's poin, will see if he can see any vacuum leaks. I wouldn't know where to look.

[18Fiatsandcounting]

Causes for concern?

Yes, running this high on the temp gauge is not right. Some possible causes (in order of likelihood):

1. Running low on coolant. Lots of posts about how to make sure it's totally full.
2. Clogged cooling system (pretty common with age). A good radiator shop should be able to fix this.
3. Stuck thermostat. They do age and go bad.
4. Fan switch that isn't coming on at the right temp.
5. Cooling fan not working (blown fuse, bad connections, see #4 above).
6. Engine running too lean. Possibly, but not likely at this point.
7. The temp gauge is simply wrong. It does happen.

-Bryan

[aj81spider]

One thing to check is the hose from the air filter box to the intake manifold. I had a fuel injected Spider that had a scary symptom of suddenly losing power at highway speed very intermittently. There was no rhyme or reason to it and I had a hard time finding it. Purely by accident I discovered that the big air hose that goes over the top of the engine had a crack where the little nipple comes out of it. It was on the lower side and hard to see. Apparently once in a while things would flex enough to open the crack and let enough air in to affect the engine.

This may or may not be what is causing your problem, but it's five minutes to take the hose off and check it all over.

[maxm50]

Sorry. TMI. Basically I need to idle around 2500 to avoid the possibility of stalling out.

Is there a checklist or something people use to know why it might not be getting enough fuel / stalling out at awkward times?

Turning the idle up to 2500 is certainly not a "tiny bit". That's a pretty radical change and personally I would NOT drive the car until you fix it, period. Idling that high would definitely contribute to overheating, if you're in low-speed or stop-and-go traffic.

I think you'll either need to start getting pretty familiar with what's under your hood (nothing is terribly complex, really), or find a mechanic that knows Fiats.

I recommend the "Resources" on the NJFiats website: http://www.njfiats.org, especially Brad Artigue's FI manual. That has a great procedure for diagnosing all sorts of fuel injection issues.

In short - it definitely sounds like you have a vacuum leak. I'd start by replacing the rubber intake hose (the large black one that runs from your air filter to your intake) as mentioned above, and also replace every single vacuum hose in the engine compartment if they are original. Then, start it up and see if it will idle properly. Then start spraying carb cleaner at every other air leak source - fuel injectors, brake booster check valve, throttle butterfly shaft, all hose connections, and see if you have another leak somewhere. The idle will momentarily rise as the vacuum leak sucks in the combustible gas.

If this sounds like too much for you, either take it slow and learn as you go, or get ready to become real friendly with a mechanic

[evrenosogullari]

So. I don't think idling screw was ever the issue.... @maxm50 agreed, I've adjusted the idling as it was, to be a little under 1000 and was fine today until....

The problem has gotten worse. What everyone is saying about a valve leak etc sounds like it could be right. Someone suggested they had a similar problem once and it turned out to be a rusted-out gas chamber needing replacement... The car is acting like it's starved for gas when tank is full....

Intake (big black plastic thing over the engine) doesn't seem to have anything save a tiny crease on the nipple that could be a crack....

I managed to get a good video of what was happening today when I get to a stop light (I'm just gently giving it gas trying to keep it going):
https://drive.google.com/file/d/1TUY5Xq ... sp=sharing After waiting a few minutes it then restarts fine.

Weird thing is I managed to get home by throwing the car (it's an automatic) into neutral whenever I wanted to slow down and break. That seemingly got me home without any problems.

Now to find the culprit....

[18Fiatsandcounting]

The car is acting like it's starved for gas when tank is full....

I know it sounds crazy, but try running the car with the gas cap loosened a turn or so. It kinda sounds like you're developing a vacuum in the tank which is preventing the fuel from getting to the engine.

Also, when you mention the idle is a little less than 100, I assume you mean 1000 rpm, right? Normal idle speed is around 850 rpm, or just slightly below the "10" mark on the tachometer, but the Fiat tachometers are not known for being that accurate at low engine speeds.

-Bryan

[evrenosogullari]

@18Fiatsandcounting Yes, sorry 1000 (just below the "10" on my gauge).... I think I've been on the wrong path being concerned with the idling rate.

I'm going to take it to my local mechanic Monday. I'm still looking for someone who REALLY knows Fiats in the Manhattan/Brooklyn area. I think I may have found someone near Arthur Avenue in the Bronx but will need to get the car in decent shape to get back up there.

No idea where the leak can be coming from... or air may be getting in? Any suggestions for places to look would be greatly appreciated. Again, didn't see any obvious tubes disconnected under the hood...

[18Fiatsandcounting]

Let us know what you find out from the mechanic. I looked at the video (thanks for that), but it was hard for me to hear the engine unless you revved it by pushing on the gas. However, it did seem like the tachometer was bouncing around but the background engine noise was constant. I could be wrong about that.

So, one possibility is that your tachometer is goofy (can be caused by an ignition problem or a loose wire), although you still do have the issue that the engine dies on you, which is real.

-Bryan

[evrenosogullari]

Yes I believe the engine sound itself was bouncing up and down too then finally shuts off (I'm not touching anything with my foot in the video except the moment when I clearly lay my foot on the gas)

It starts fine... I drive for about 5 minutes then all of a sudden it starts stalling out like that (what the tachometer was doing the engine is also doing i think - unless the tachometer could be affecting the engine). It did it literally as I was driving at top speed (a little scary when going over a bridge or on a highway). I have to stop. Wait a few minutes. Then it's okay for another 5 minutes. I was able to get home by shifting in neutral whenever I want to slow down. Its an automatic. When I stay in drive and gently hit the brake to stop at a light it does this little dance until it stalls out.

Going to take it to the mechanic today but again he's not a Fiat expert! We'll see if he's able to figure it out

[18Fiatsandcounting]

I do recall having another car (not a Fiat) that had a partially bad EGR system, and it would sort of behave like your spider although not nearly as extreme, but it wouldn't stall. The EGR system worked well enough to pass smog tests, but something wasn't quite right in the idle.

-Bryan

[evrenosogullari]

I'm wondering if this could be my issue:
https://fiatspider.com/f15/viewtopic.ph ... 88#p299388

I've ordered a new Air Flow Meter and am going to try replacing that.