Engine Performance problem
1993 GMC Jimmy 6 cyl Four Wheel Drive Automatic
My jimmy has a vortec 4.3 it runs fine for a few miles then stalls and wont start for hours or days. I changed the icm, no help. So I changed the rotor and cap, no help, then coil, no help. So I checked the coil for spark by taking a plug wire and putting a spark plug in it but didnt see any spark. It wont start at all now. Do you know what the problem can be?
Do you have primary voltage to the coil, pink wire, goes hot when you turn on the key? Does the rotor turn when you crank it? The white wire from coil, should have a pulse. Could be issue with pickup coil? I'd check wiring circuits first.
The spark plug you used for testing was grounded to the engine block?
May, 26, 2010 AT 2:51 PM
Went out this morning and it started right up even with the spark plug wire still laying on the valve cover, and yes, it was sparking away. After about 2min it died and now there is no spark. Since it starts when its cool doesnt that answer the questions about the rotor turning etc? And that the wires are working? But what would make it work or not depending on operating temp?
May, 26, 2010 AT 3:04 PM
I'd have to test when the problem is ongoing. Testing when everything works fine, doesn't tell you anything. I already asked about primary voltage at the coil, when no spark, you didn't answer? Maybe somebody else can help you better, have a good day.