The Starting Fluid Test
The starting fluid test is usually the first test I run when doing an engine no-start diagnostic since it helps me quickly determine if a lack of fuel is causing the problem.
Now let me tell you that using starting fluid is not the most accurate way to diagnose a bad fuel pump.
But it will steer your troubleshooting efforts in the right direction by confirming whether a lack of fuel is behind the engine's no-start problem or not.
IMPORTANT: If you haven't checked all six spark plug wires for spark yet, please do so before performing the starting fluid test. I recommend using a dedicated spark tester for the spark test.
OK, these are the test steps:
- 1
Remove the intake air duct from the throttle body.
You don't have to completely remove it, since you'll have to reconnect it in one of the next steps. - 2
Open the throttle manually, and spray starting fluid down the bore.
- 3
When you have sprayed a good squirt of starting fluid, quickly reconnect the air duct to the throttle body (you don't have to tighten the hose clamp).
Reconnecting the intake air duct is a very important safety precaution in case you get a back-fire thru' the intake manifold. - 4
Crank the engine once the intake air duct is back on the throttle body.
- 5
You'll get one of two results with this test:
1.) The engine will start momentarily and after a few seconds will die.
2.) The engine will only crank but not start at all.
OK, let's interpret your test results:
CASE 1: The engine started and ran for a few seconds. This test result confirms that the engine isn't starting due to a lack of fuel.
The most likely cause of this lack of fuel is a bad fuel pump.
CASE 2: The engine did not start, not even momentarily. This test result tells you that the engine's no-start problem IS NOT due to a lack of fuel.
It's important to note that this the accuracy of this test result depends on having all six spark plug wires sparking.
If this info saved the day, buy me a beer!
