How to diagnose a problem that only occurs intermittently?
One strategy for diagnosing a stalling problem that only occurs intermittently is to wait until the problem gets worse before you attempt to diagnose it. It’s always easier to find a part that has failed than to find one that works most of the time and only acts up occasionally.
What causes a car to stall after replacing the relay?
Replacing the relay usually cures the problem. Another cause of stalling that is often overlooked is bad gas. Moisture sometimes finds its way into underground fuel tanks, and engines don’t run very well on water. Sometimes alcohol additives may not be properly mixed, or may separate from the gasoline in the presence of water.
What causes intermittent stalling in a car engine?
More Causes. One of the more unusual causes of intermittent stalling we’ve heard about is a defective vehicle speed sensor. When the vehicle stops moving, the PCM may not engage the idle speed motor (carbureted engines) or idle air bypass motor (fuel injected engines) so the engine will idle normally.
What causes a no spark condition open loop?
If after unplugging the 4-plug connector there is no spark or the spark still looks weak, this tells you that the problem is in the major ignition components like the stator, coils, cdi, spark plugs, spark plug wires, possibly a short in the wiring harness, a bad trigger coil or on EFI models your Injector Coils are bad (they measure 19-20ohms).
When does a car engine have no spark?
If a connecter becomes 100% disconnected or if a wire gets cut then the switchwill no longer turn off the engine but the engine will still start and run. Diagnosing no spark, weak spark or intermittent spark issues
How to diagnose no spark or weak spark?
Diagnosing no spark, weak spark or intermittent spark issues First is separating the issue between switches or the primary ignition components like the stator, cdi, coils, trigger coil or possibly plugs or plug wires or plug caps.
Can a spark plug make a motor run poorly?
Spark plugs with the gap set too small on them can make the motor run poorly. If you have no spark and your trigger tests ok, your stator tests ok and you have tried a new set of coils then we’re possibly looking at a bad CDI box. There is no real good way to test the CDI other than swapping the box out with a known good CDI box.