Alfa Romeo Forums banner

1 - 3 of 3 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter #1
Have been fighting this problem for a month now with no avail. I have a 1980 Spider with a Merriliplex ignition. It has two magnetic pick ups in the distributor. The coil stopped sparking after I changed a leaking oil pressure sender (I know, it hasn't got a thing to do with the ignition). Tested all the ohms, current, and grounds, and found the original system to be all within range, except for the secondary coil reading. According to the manual, it should have 10K to 11K omhs between the HT and negative or positive poles on the coil. I had a reading of 7.8K ohms. I called International Auto, and they advised that it was probably the coil. So I bit the bullet and bought the "new" dry coil they recommended and bought another single trigger to replace the double as per their suggestion as well. $200 later, I got the parts and decided to test the new coil. Secondary reading was lower than my original coil at 5.6K ohms. Installed the coil, no spark. So I went to my back up plan of installing the single trigger. Installed it to spec, tested the ohms at 726 Ohms which was within the 700-800 ohms it called for and cranked the motor with again, no spark.

I'm not an Alfa expert, but I do know my way around cars and ignition systems. But just to make sure I didn't miss anything, this is what I get:

Readings from the tigger 726 ohms, range 700-800
Readings from trigger to dist body, infinity ohms (no continuity)
12.8 volts to positive side of coil
Good grounds on motor and Finned coil housing
Primary coil readings .75 ohms
Secondary coil readings 5600 ohms

Old coil had the ignition module, condesor, white Tach wire on the negative side of the coil, and ignition switch power and the ignition module was on the positive side.

The new coil has just the ignition module and tach wire on the negative and ignition module and switched power on the positive.

I have check all connections for continuity and correctness and I am completely out of solutions. I even swapped out the battery with no luck and disconnected the oil pressure switch. I'm hoping someone can find something wrong I did but I'm out of answers. Anyone? Please? Thanks Allan
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
Is there battery voltage at the coil positive terminal with key on and when engine cranking?
 

·
Registered
Joined
·
36 Posts
Discussion Starter #3
Hi Jim, I believe so, I used a test light between the positive and negative sides of the coil and it lite up while cranking, with a pulsing glow. But I think I understand your line of questioning. I'll put a volt meter on the positive side tomorrow and see if I am getting a full 12 volts. But I have to say, the engine cranks enthusiastically so I didn't think about a possible short while cranking. Thanks and I'll let you know. Maybe if the ignition switch is shorting out the coil lead, I'll string a positive line directly from the battery to the coil and see what happens, Allan
 
1 - 3 of 3 Posts
Top