All the ways. 16v , example. 8v , skip test 4 , and only check the 1 injector, and the injector is 1 ohm not 10 ohms.
Assumes fuel pressure in 30-40 range ,ever at near 60 psi.
1: Fuel pressure leak down injectors unplugged, pass or fail.?
If the leak down fails , there is good chance the injector leaks, block the return line, under pressure just 1 second (helper) after turning key off, if the leak down still happens the injector(s) are leaking.
2: Injector ohms 10-15 ohms, good, open or shorted bad. (disconnect the connector , insert ohmeter (resistance range switched, on any DMM)
3: Wires good. LOOK ! (at injectors, front of right of motor , firewall connector and ECU ?) damage is easy to spot, just LOOK.
4: 12vdc on all 8 pins of injectors , KEY ON. all must be equal ! , KEY ON, not running, and all connectors attached.
If not equal and test 2 passes above then the wires are bad or ECU is bad. (skip on 8v)
5: Check ECU for shorted output drivers , with an ohm meter. "infinity" with injectors connectors , unplugged , ring out the non blue-black wires, using an ohm meter, key off. Infinity is the expections.
On 8v motors both wires on the injector must read infinity.
if that fails, ECU is bad, unplug ECU , if still fails,then harness is bad, you missed the damage checks.
6: All 4 injectors click cranking.? right? (1 on 8v) if not ECU and injectors are not working.
7: The NOID LAMP test , must be out (no glow) on ALL 4 injectors , one a time, KEY ON? no cranking. injector unplugged.? ( if not that is harness or ECU short)
The connection on test 7 is at the injector harness connector. never the injector.
8: The NOID same connections , but now you crank engine, do they flash? no flash or glow is bad wires, (open) or bad ECU.
It goes with out saying, if all tests pass and the injector leaks or dont squirt , the injector is bad.
If the Injector pulsewidths (lean or rich) are wrong at idle or at 2500 rpm, then the ECU has bad sensor input or fuel pressure is wrong.
If injector pulsewidths are perfect (and AFR is wrong) then the injector is bad (clogged partially is usually the case, send them out for cleaning) Witchhunter.com is best.
PCM=ECU=ECM , AFR is air fuel ratio. NOID is a tool that check injector signals (a $2 lamp)
rev 1 ++++ 3-12-2011