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Discussion Starter · #1 ·
Hi all, I've been dealing with this issue for a while, and now I finally have the time and funds to tackle this issue.

Background: 1977 Alfetta Sport Sedan with a 1981 Spider motor swap after the original motor blew. After the swap (done by local reputable Alfa specialist) I was driving on a straight-away, and the car sputtered (as if it was out of gas) to a stop. Gauge showed between a quarter and half tank. Haven't been able to get it started since. It cranks, but will not start.

My initial thought was a fuel issue:

-Added 4 gallons of fuel
-Replaced rear and front fuel filters.
-Replaced fuel lines.
-Tested fuel pump
-Confirmed adequate fuel pressure

Still no start.

-Tried starting fluid - no start.


This leads me to believe it is a spark issue:

-Cleaned the plugs - no start
-New plugs
-New wires
-New battery fully charged at 12.6V and drops to 10.9V while cranking.

Still no start...

Stumped! Any suggestions on what's next?
 

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Look inside the distributor cap. I've seen the carbon button in top/center fall out. And I've seen the rotor lose its tip.

I don't recall if there is a fuse for power to the coil. But that could be worth checking. And if you have the bullet fuses with an aluminum strip consider replacing them even if they look good. The brass strip fuses are better - somehow the aluminum strip can appear OK but fail to allow electrons to flow.

And if all the above checks out, it's possible the ignition switch may have failed. It might be making contact in the start position but not the run position (the contacts that sends power to the coil for ignition). I don't have an Alfetta wire diagram but it is likely the same/similar to the Spider's (sketch below from shop manual). See if you get 12V when the switch is turned to 'on' (run).
 

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No spark is most likely but I would verify it first by pulling a plug, laying it on the valve cover and cranking the engine. Bright white/blue sparks are good, dull red/pink sparks are bad.
What kind of ignition do you have - points, marelliplex, .....?
 
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Discussion Starter · #4 ·
I will take a look at this today. I forgot to mention, I installed a new ignition switch when I bought the car - it had no keys. Would this cause the car to sputter and stop? Thanks for your reply!
 

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Look inside the distributor cap. I've seen the carbon button in top/center fall out. And I've seen the rotor lose its tip.



I don't recall if there is a fuse for power to the coil. But that could be worth checking. And if you have the bullet fuses with an aluminum strip consider replacing them even if they look good. The brass strip fuses are better - somehow the aluminum strip can appear OK but fail to allow electrons to flow.



And if all the above checks out, it's possible the ignition switch may have failed. It might be making contact in the start position but not the run position (the contacts that sends power to the coil for ignition). I don't have an Alfetta wire diagram but it is likely the same/similar to the Spider's (sketch below from shop manual). See if you get 12V when the switch is turned to 'on' (run).
Super write-up. I spent weeks trying to figure out what made the darn thing would occasionally start then die off a few minutes later. Removed the distributor cap and surprise surprise, there was the center pin (carbon bit) sitting over the rotor... The cap had a small crack and the spring was pushing the small pin out of contact untill it eventually fell out. Replaced the distributor cap (and eventually moved on to more "manly" problems like cracked crankshaft ).
Another couple of instances which had me stomped were when it would misfire and stuter in mid-race on its maiden track day ... Turns out mechanic had managed to brake the sleeve on the wire feeding the bottom of the dizzy and left one of the two wires with just enough contact to leave his workshop and embarass me the next weekend on the track...
With the gtv fuel pump, it would cut out in the middle of a busy intersection in mid-traffic then jump back in full vigor the minute I decide to replace it. Turns out the lead wire had been pulled almost completely out and hanging by a couple of threads which eventually let go. Some cleaning and silicon/rtv and the pump was back in action (so far)...
Let me just add that a visual check is fairly easy by just holding the spark plug cable a few millimeters above the cam cover and see if it "sparks" while a helper turns on the ignition switch (use a screw driver if the sleeve is too deep).
Same thing with fuel supply, just stick the feeding hose into an empty plastic bottle and confirm fuel delivery. Hose Fuel line Auto part Pipe Auto part Fuel line Fuel pump

Sent from my F8332 using Tapatalk
 

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I don't know where the washer came from. But it looks to me like there are cracks or carbon tracks around the center button. These can allow the electrical energy to 'leak' to places instead of to the rotor and on to the spark plug wires. I suggest a new cap. And rotor - sometimes a cap from one manufacturer and a rotor from another don't play well together. Either the gap from the rotor tip to the spark plug terminals can be too big (making the spark have to jump extra distance) or too small (and the rotor tip can whack the terminals breaking one or the other or both).
 

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Discussion Starter · #8 ·
I'll order a cap and rotor from Centerline tonight. I'll update after installing the new set. Thanks for your help!
 

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I don't know where the washer came from. But it looks to me like there are cracks or carbon tracks around the center button. These can allow the electrical energy to 'leak' to places instead of to the rotor and on to the spark plug wires. I suggest a new cap. And rotor - sometimes a cap from one manufacturer and a rotor from another don't play well together. Either the gap from the rotor tip to the spark plug terminals can be too big (making the spark have to jump extra distance) or too small (and the rotor tip can whack the terminals breaking one or the other or both).
Yep, that is some definite carbon tracking!
 
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Discussion Starter · #11 ·
No spark is most likely but I would verify it first by pulling a plug, laying it on the valve cover and cranking the engine. Bright white/blue sparks are good, dull red/pink sparks are bad.
What kind of ignition do you have - points, marelliplex, .....?
I have Marelliplex - we made the switch during the swap. Looks like the distributor cap wasn’t addressed though.
 

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Discussion Starter · #12 ·
While waiting for the new parts, connect your voltmeter's red lead to the coil + terminal & the black lead to ground. What does it read when you turn the key to 'on'?
I’ll take a look at this tonight. New parts due to arrive tomorrow.
 

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Discussion Starter · #13 ·
While waiting for the new parts, connect your voltmeter's red lead to the coil + terminal & the black lead to ground. What does it read when you turn the key to 'on'?
Before installing new cap and rotor I tested this. Voltmeter read 10V when key first turned. While cranking it dropped to 7, almost 8V.

New cap and rotor now installed, still only cranking with no start. Anything else I can check before towing to the shop?
 

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Pull one of the plug wires from the distrubutor cap and plug it into the coil in place of the wire that goes to the distributor cap. Rest the plug on the engine and crank it, You should see a bright spark.
If you see the bright spark then put the HT wires back in the original places and repeat the test. A bright spark means that your ignition is OK.
If you have a good spark in the first test and a weak or no spark in the second test then you have a distributor cap/rotor problem.
If you do not have a good spark in the first test then you have a problem with the Marelliplex or its associated wiring.
Marelliplex is simple. The pickup in the distributor send a pulse to the 4 pin module that is on the heat sink causing the module to fire the coil. You should be able to find a circuit diagram if you Google Marelliplex.
 

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Pull one of the plug wires from the distrubutor cap and plug it into the coil in place of the wire that goes to the distributor cap. Rest the plug on the engine and crank it, You should see a bright spark.
If you see the bright spark then put the HT wires back in the original places and repeat the test. A bright spark means that your ignition is OK.
If you have a good spark in the first test and a weak or no spark in the second test then you have a distributor cap/rotor problem.
If you do not have a good spark in the first test then you have a problem with the Marelliplex or its associated wiring.
Marelliplex is simple. The pickup in the distributor send a pulse to the 4 pin module that is on the heat sink causing the module to fire the coil. You should be able to find a circuit diagram if you Google Marelliplex.
alfaparticle: I like this diagnostic; it's a good alternative to using an inline spark plug tester.

One other thing to check: If the distributor was not properly secured, it might have rotated enough to result in a no-run engine.
 
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Discussion Starter · #16 ·
Pull one of the plug wires from the distrubutor cap and plug it into the coil in place of the wire that goes to the distributor cap. Rest the plug on the engine and crank it, You should see a bright spark.
If you see the bright spark then put the HT wires back in the original places and repeat the test. A bright spark means that your ignition is OK.
If you have a good spark in the first test and a weak or no spark in the second test then you have a distributor cap/rotor problem.
If you do not have a good spark in the first test then you have a problem with the Marelliplex or its associated wiring.
Marelliplex is simple. The pickup in the distributor send a pulse to the 4 pin module that is on the heat sink causing the module to fire the coil. You should be able to find a circuit diagram if you Google Marelliplex.
Thank you so much - I’ll do this
 
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