Symptoms: cranks strong, fires, and then dies as the ignition key switches from starting to running. (Note that if you replaced your stock starter with a gear reduction starter and did not wire-in a solenoid to bypass the ballast resistor when cranking, then your symptom will be simply crank with no start).
Diagnostic: Clean gas in the fuel filter. Airways were unclogged. I had a blue-white spark between the cylinder head and the screwdriver I stuck in the primary wire from the coil when cranking. Didn't get shocked this time. lol
But I decided to check coil on the meter anyway. Coil checked out with 1.6 Ohms internal resistance. The ballast resistor also checked out with 1.6 Ohms resistance, but the reading was hit and miss, ranging from infinite resistance (open circuit) to the correct value. And readings were all over the place. I initially assumed this was just because my leads had trouble finding good clean contact.
I would have started looking elsewhere for the problem, but in TunerStudio* I noticed tach values jumping a lot during cranking. My tach signal comes from the coil positive, so I knew something was going on in that neighborhood.
So I swapped the coil with an extra from the parts bin: same thing. Swapped the ballast resistor from another parts bin: Vroom!
Lesson: When you crank and the engine fires but dies right away (or doesn't fire), put the ballast resistor on the list of things to check, even if it kinda passes the Fluke test.
* I run a fuel-only Megasquirt fuel injection system that talks with TunerStudio. A lot of tuners use it, and it might also work with the Holley system a lot of people are putting on their 2Fs. Here, TS wasn't necessary to locate the problem, but it kept me looking in the right place.
Diagnostic: Clean gas in the fuel filter. Airways were unclogged. I had a blue-white spark between the cylinder head and the screwdriver I stuck in the primary wire from the coil when cranking. Didn't get shocked this time. lol
But I decided to check coil on the meter anyway. Coil checked out with 1.6 Ohms internal resistance. The ballast resistor also checked out with 1.6 Ohms resistance, but the reading was hit and miss, ranging from infinite resistance (open circuit) to the correct value. And readings were all over the place. I initially assumed this was just because my leads had trouble finding good clean contact.
I would have started looking elsewhere for the problem, but in TunerStudio* I noticed tach values jumping a lot during cranking. My tach signal comes from the coil positive, so I knew something was going on in that neighborhood.
So I swapped the coil with an extra from the parts bin: same thing. Swapped the ballast resistor from another parts bin: Vroom!
Lesson: When you crank and the engine fires but dies right away (or doesn't fire), put the ballast resistor on the list of things to check, even if it kinda passes the Fluke test.
* I run a fuel-only Megasquirt fuel injection system that talks with TunerStudio. A lot of tuners use it, and it might also work with the Holley system a lot of people are putting on their 2Fs. Here, TS wasn't necessary to locate the problem, but it kept me looking in the right place.
