Cadillac Owners Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
1993 SDV is turning over and getting fuel, but spark is very weak. Replaced battery and coil to no avail. What's next? I'm pretty clueless on GM ignition systems, having been a lifelong Ford guy.
 

·
Registered
94 Fleetwood Brougham
Joined
·
7,534 Posts
Is timing off? The HEI is a mean distributor. More power than almost any car ever needs. Can arc gaps at 0.080" in a single bound.... (Olds V8's in the 70's were 0.080" gaps factory....)

Is the carbon button under the coil present and in good shape? It is a resistive part to keep down RFI. Make sure the grounds are good between the coil and the metal bar that connects the coil frame to the HEI connectors in the cap. Clean any rust on it.

Are you getting 12V to the HEI? Check the BAT terminal, the fat red wire coming in. Check and check under load (engine cranking). You can run a new wire from that term to the battery, but that will have to be disconnected to shut the engine off if it works.
 

·
Registered
Joined
·
305 Posts
Plus check the resistance of wires. New wires are between 4 and 8 kOhm. My old ones were 5 -11.3 kOhm. My old plugs (original with 140.000 m !) had 0.075 gap but car ran just fine. The gap is supposed to be 0.06.
 

·
Registered
94 Fleetwood Brougham
Joined
·
7,534 Posts
I think GM specs no wire should ever be greater than 15K no matter the length.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #5
N0DIH said:
Is timing off? The HEI is a mean distributor. More power than almost any car ever needs. Can arc gaps at 0.080" in a single bound.... (Olds V8's in the 70's were 0.080" gaps factory....)

Is the carbon button under the coil present and in good shape? It is a resistive part to keep down RFI. Make sure the grounds are good between the coil and the metal bar that connects the coil frame to the HEI connectors in the cap. Clean any rust on it.

Are you getting 12V to the HEI? Check the BAT terminal, the fat red wire coming in. Check and check under load (engine cranking). You can run a new wire from that term to the battery, but that will have to be disconnected to shut the engine off if it works.
Carbon button appeared to be in ok shape. That spring coming up from the rotor looked flimsy, but it stood upright. I replaced the metal bar when I replaced the coil, so it's good to go. Timing should be ok. It was fine one day and the next it wouldn't start. Not that I think it should matter for anything, but 2 days before it started doing this I replaced the radiator due to a leak.
 
1 - 5 of 5 Posts
Top