1986 328 loud engine clicking sound and stalling. Diagnosis?

I had very similar symptoms recently with my 1985 308, the motor of which is very similar to yours. I attacked a number of things in what I thought was a logical order and the problem was resolved. Unfortunately, I'm not exactly sure what fixed it. (My guess is a failing crank position sensor.) I had the intermittent clicking sound as well and it also sounded to me like spark arcing. Why don't you try to get the car started in the dark to look for arcing? If you don't see any, I'd be glad to take you through the steps that I followed.

 

Consider getting a stethoscope from harbor freight etc to help isolate the nosie .. I find them very helpful ..

https://www.harborfreight.com/mechanics-stethoscope-63691.html

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Have you looked to see if the belt is rubbing against the coolant pipe?

 

Pull the plug leads off the plugs and look for holes/ burn marks on one or more of the extenders.

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Very difficult to diagnose from the video. As suggested, a stethoscope would be good to isolate where the ticking is coming from. You could try the poor man's stethoscope - a 2-3 foot piece of hose. Hold one end at one ear and direct the other end to different areas. Not as precise as a real stethoscope but often good enough! Isolating the location of the sound would be a major aid!

FWIW...from the audio, it doesn't sound like arcing to me. Arcing has more of a "SNAP" sound than what I'm hearing. Of course, that could simply be the way the phone(?) mic is picking it up. But it sounds more metallic-like to me. The pattern also doesn't sound like secondary arcing - three tics, then a delay, three more, etc. Also, it is much slower than engine RPM whereas arcing would be expected to occur with every firing cycle of the affected cylinder(s). Distributer cap arcing, could be more random, but again, the sound seems wrong to me.

Slap a stethoscope (or hose!) on there and see what you come up with!

 

In the meantime still inspect the plug extenders. Burn through is very common, will cause a misfire & may well make a noise.

Should take you about 5 minutes to pull the lot

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The clicking sound sounds like classic belt slap, might just be the ac belt, it can make this sound after a few years of age but would go away after the warm up period. It is because of a hard plastic spine in the belt that it can do this when cold. Might be completely unrelated to the drivability problem you are having. When was the ac belt last changed? Turn the ac on and off and see if the snapping sound changes when the ac compressor is under load.

The other cause of arcing has been noted, but ruling out spark arcing is an easy thing to do, remove each plug wire (and the extender attached to it and the plug) and you will see a black mark on the extender where there is arcing if that is what is happening. It is a common problem with the extenders. Do this with a couple of the easy to access ones as a start and see how things look.

Beyond that, the usual approach to diagnosing these things is to rule out plain and obvious issues, like split or leaking vacuum hoses, check a spark plug to see if it is fouling or the gap has widened too far out of spec, checking electrical connections, basically easy to do inspection type things that do not take much labor and help rule out some basic things and cause you to look around and inspect things carefully. The engine seems to run smoothly enough in the video, but then there is some surging near the end of the video, which suggests a fueling problem rather than spark.

I am going to make a wild guess that one or both of the check valves for the air injection system have corroded and the internal rubber diaphragm has failed, sucking exhaust gas directly into the intake and screwing up the fuel air mixture. These things should be replaced routinely, but rarely are unless one fails. Here is an old thread on the item...https://www.ferrarichat.com/forum/threads/air-injection-system-328.389754/ The OEM part for this is ridiculously priced, but this is the same item functionally (and looks pretty much the same) and works fine on my 3.2 Mondial which has the same engine as yours. https://www.amazon.ca/gp/product/B000C7Z9U2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

It sounds like static electricity. The stalling part could be related if too many cylinders do not ignite every cycle.

I also agree that belts might make this sound too, but I vote for the extenders ...

 

As I mentioned, I had exactly the same situation as you describe. There was a good deal of variation in late 308 and early 328 motors, but if yours is very similar to mine I suggest checking the following: vacuum leaks certainly; auxiliary air valve; disconnect cold start valve to see what effect that has; disconnect oxygen sensor to see what effect if any that has; check grounds to Digiplex boxes and run new ones in any event.

Have you opened your distributor caps to see how things look inside? Check grounds and connections to coils.

Have you used a timing light to check timing on each bank? In my case, the front bank seemed to have erratic timing.

I was going to have my Digiplex boxes rebuilt anyway and went ahead and had it done. Even though my crank position sensors showed the appropriate electrical resistance, I replaced the two (there are three in total) which are not horribly difficult to get at. One of those "serviced" the bank of cylinders which seemed to have erratic timing.

I was told by the rebuilder (Dave Feinberg) that both Digiplex boxes tested okay on the bench. But that does not mean that they are necessarily okay in operation. Also, despite the fact that the crank position sensors at the appropriate resistance, that does not necessarily guarantee that they are okay in operation.
With all the checking of other bits, nothing seemed amiss. My problem came on suddenly as well and when all was put together with the new boxes and sensors, my problems were solved – both the idle issue AND the mysterious clicking. My guess is that the problem was a sensor or Digi box.

I am not necessarily saying that you have the identical problem, but hope this is helpful. I was beginning to think of fuel issues, but remember that "90% of "fuel issues" are actually ignition issues."Good luck.

(I have an apartment in New York City as well, although my cars are in Eastern Long Island, so I understand what you mean about the garage.)

 

I was thinking the rpm at 1000 is about 17 revs per second and two for each spark. It is similar to some of the spark sounds in the video.

 

My mysterious clicking, which at least seems similar to what's described, came and went with my ignition/idle problem. There was no other mechanical issue. That's why I would still wonder about "spark sounds."

 

I have not seen the extenders in black on the late cars, they are usually red, I think black was for the older 308's, maybe others can chime in if there is a technical difference? As for the check valve, you could remove the hose on one, and while the engine is running there should not be exhaust gas coming out. Sounds like you can still start the car to do some checks?

 

My '85 308 has black extenders. Of course I don't know if they are original. They have close to zero resistance. I bought new red extenders, which I have not yet installed and they have 2000 ohms resistance. Supposedly this is correct for late 308's and, I am guessing, early 328's. When I asked Sarasota garage guru David Feinberg about this, he said what seemed to me to be high resistance is advantageous, since it apparently extends the spark time.

 

+1 correct extenders for a 328 are red as far as I know. I think the difference is something to do with resistance

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My experience was the original QV extenders are resistive (around 2k ohms) and the 328 red extenders are 0 ohms. I have never had any issues after I replaced the original QV extenders with the later style. Several of my QV extenders were defective.

 

Usually you need some resistance in the circuit from the coil to the plug and back. This will allow for a nice, good duration spark. If the extenders, the coil or HT lead is resistive, is a matter of design choice and to minimize RF interference. Not sure how the 308 vs 328 design is in this respect.

Of course, any cracks in the extenders or insulation issues with the HT leads will create shortcuts for the energy from the coil. Maybe use some Kapton tape on the extenders to see if there is a difference.

Note that Kapton tape is not good in moist environments or where the tape may get knicked. It can easily develop cracks over time. Then they will not insulate anymore and turn into a conductor instead.

 

I know we are on the issue of extenders. But it seems to me that degenerating extenders would start with a single cylinder misfire and gradually move on from there. That doesn't seem like the problem here.

 

I should've mentioned previously that you should check your alternator. Start the car, rev it a bit and then put a voltmeter across your battery while the car is idling. On the late 308 you should get 13.7 V and I believe it is the same for your car. I have it on good authority that a failing alternator can cause strange ignition problems on these cars that can be hard to diagnose.

 

A helpful troubleshooting technique for me is to pull the spark plug extenders slightly off the spark plugs so that they are detached from the plugs, but still in close enough proximity that the spark will jump and the engine will still run. Then I crank it up. I then can use insulated pliers to pull each extender away from each plug momentarily one by one as the engine is running. You’ll soon find if you have a “dead” cylinder. This way you can pinpoint where the trouble lies.

 

Don't fool around with all this troubleshooting until you isolate the sound (stethoscope or whatever). ONCE you know what component(s) is producing the noise, you can proceed with effective/efficient repairs!!