how do you check injectors i think everything is working except my injectors i have power and spark and fuel pressure but no conbustion any idea's ?

unplug the electrical connection. the red wire should always be 12v+ (around 14 volts). with ignition on , the black wire should be 12v negative (around 14 v negative). just unplug one at a time.

With an ohmmeter.To check for power/ground suuply use a noid light.Its like an LED that is injector driver safe.Using a conventional test light will blow the drivers out of the ECM.

NM50 wrote:With an ohmmeter.To check for power/ground suuply use a noid light.Its like an LED that is injector driver safe.Using a conventional test light will blow the drivers out of the ECM.

How about a multimeter? What are the drivers in the ECM? My O2 sensor wire melted to manifold and stayed that way for a couple months. I assume that is a short. My computer did end up being faulty. My new computer seems to be acting up too, though. I dont really understand why computers start causing rich condition and things get worse and worse.

btw, i was getting 12.4 ohms on my injectors.

If you're checking them all because you think they're not operating :

1) Check for power to injectors. KEY ON . with dvom or test light back probe the injectors. If you're just checking for power it doesn't matter what side or which terminal you check. The ECM grounds the injectors so voltage will be the same through out the circuit. Only double check the circuit if you get a low voltge or weak test lamp. BATTERY VOLTAGE SHOULD EXIST.( ok )

2) Check the individual injectors. KEY OFF . Disconnect the injector connectors (although back probing is ok ) Check resistance across the injector. It should read between 11 and 15 ohms.

3) Check for injector fire. With a noid light , disconnect one injector , then crank the engine and see if it flashes. If it doesn't, disconnect all the injectors and check each cylinder/injector circuit individually. If by chance the same test you did on the first cylinder suddenly works with the injectors disconnected, you may have high resistance in the power supply circuit to the injectors. EXAMPLE--A partially broken wire with only a couple of strands will show full voltage , but , won't have the capacity to operate the injector (like: you can't activate a relay with a test light).

4) If all the circuit tests are passed and you have fuel pressure (and you have good fuel pressure and compression and you have good fuel etc. ) You can either pull the fuel rail and check for spray or shoot some flamable carb clean into the intake and crank and see if it has a short start.

That's it for now. good luck.