What engine test can be used to pinpoint the cause of a low cylinder compression test reading?
Running a compression test or dynamic compression test is an important, but little-used and often overlooked engine diagnostic tool. Why is this test so significant? It can be used to pinpoint the cause of a misfire when all the usual tests return normal results.
How do you test for a fuel injector leak?
To do the test, with key ON engine OFF, presurize the fuel rail, then pulse the injector using the pulser for a specific period of time. The longer test is more accurate. Do the same for all cylinders and record the lowest pressure drop. A 1 PSI different between injectors is enough for you to flag it as clogged.
Can a fuel injector be tested under pressure?
Fuel injector leak testing should be done under operating pressure. The average DIY fuel injector cleaning project and most automotive repair shops does not have the proper diagnostic equipment or the ability to test leaking injectors or clean them properly.
How to test a cylinder for a misfire?
MotorWeek’s Pat Goss (RockAuto.com is a MotorWeek Sponsor) shows what to check first when a cylinder misfire code shows up on an OBD scan tool. This includes how to test modern coil on plug ignition coils with a spark tester (available under “Extras” at RockAuto.com). Loading…
What can cause an OBD-2 engine to misfire?
On OBD-II cars, the OBD-II system will not only identify misfires, but also coil and injector problems. Consequently, if the (MIL) lamp is on and you find a code for a misfiring cylinder; and a second code indicating an injector fault for the same cylinder; bingo, the engine probably has a bad fuel injector.
What does it mean when your fuel injector is leaking?
Leaking fuel injectors can cause Oil Thinning At engine shutdown the fuel pressure should maintain operating pressure or just below that for a substantial period of time. Fuel injector pintle, ball or disc seat leaks as well as the bottom O-ring leak on a side feed injector will cause fuel to escape into the intake manifold.
Fuel injector leak testing should be done under operating pressure. The average DIY fuel injector cleaning project and most automotive repair shops does not have the proper diagnostic equipment or the ability to test leaking injectors or clean them properly.
Can a cracked fuel injector cause an engine fire?
Any external fuel injector leaks such as a cracked fuel injector body or bad fuel injector O-rings can cause an engine fire at any given time. At engine shutdown the fuel pressure should maintain operating pressure or just below that for a substantial period of time.
How to diagnose a hard to find misfire ( GM 4.3L )?
Removed the spark plug wire from the #1 spark plug. Attached the spark tester to the spark plug wire. Grounded the spark tester with a battery jump start cable directly on the battery negative (-) terminal. Had my neighbor crank the engine while I observed the spark tester. The result was: I had spark!