1994 Buick Lesabre Electrical / weak spark problem

1994 BUICK LESABRE
Avatar
OLDTIMER10
  • MEMBER
  • 4 POSTS
Electrical problem
1994 Buick Lesabre 6 cyl Front Wheel Drive Automatic 175k miles

Spark plugs (new) show weak, arching, yellowish spark. Not a sharp, blue snap as normal.

Tested wires, ICM, coils, crank sensor etc.

Unplugged PCM connector & checked with test light from BAT+ to the PCM connector Pins # B11,B12,B13,&B14.The test light lit bright on each.

Checked with voltmeter from Pins #WC7,WC8,&WC9 to ground and have 11.5V

From whence does this failure come?
Nov 9, 2008 at 11:33 PM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Tested wires, ICM, coils, crank sensor etc.

What was the coil primary and secondary windings resistances-what is the voltage on the coil's positive terminal when key at run position
Nov 9, 2008 at 11:58 PM
Avatar
OLDTIMER10
  • MEMBER
  • 4 POSTS
Primary side is zero Ohms with continuity. Secondary's are within range.
Nov 10, 2008 at 12:10 AM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Do you have an HEI distributor or DIS See below info and also check the distributor pick-up coil


https://www.2carpros.com/forum/automotive_pictures/12900_d1_3.jpg


https://www.2carpros.com/forum/automotive_pictures/12900_d2_3.jpg


https://www.2carpros.com/forum/automotive_pictures/12900_d3_1.jpg

Nov 10, 2008 at 12:25 AM
Avatar
OLDTIMER10
  • MEMBER
  • 4 POSTS
I believe it is a DIS waste spark system.

Coils have been load tested independent of engine with same weak spark. Also tested new coils with same weak spark. I believe I have a grounding problem. Can you tell me the locations of ground straps from engine to body?

thanks
Nov 10, 2008 at 10:48 AM
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Check ground point G120 above the AC compressor


https://www.2carpros.com/forum/automotive_pictures/12900_pcm_ground_1.jpg

Nov 10, 2008 at 2:01 PM
Avatar
OLDTIMER10
  • MEMBER
  • 4 POSTS
Removed wires, cleaned and applied dielectric grease at G120.

Also, checked b11-b14 with multimeter which check ok.

Thank you
Nov 10, 2008 at 2:10 PM