Anyone know how to diagnose a leaking fuel injector?

2007 R56 MCS, 120k km

Long story: have misfire, confirmed plugs and coil packs are good, after 2 mins of cold start idle I pulled the plugs to inspect and cyl 2 spark plug is soaked with gas. Confirmed cyl 2 has spark (so the wireharness and signal from ecu is good). Thinking that I have a leaky injector or no compression, I don't have a compression tester.

Codes:
P2783 Misfire Multi Cyl Error
P277B Misfire Cyl 4 Error
P277F Misfire Cyl 2 Error
P2781 Misfire Multi Cyl Max
P2779 Misfire Cyl 4 Max
P277D Misfire Cyl 2 Max

 

Have you considered removing the fuel rail. Pretty simple, I think there is only 2- #25 star headed bolts and the rail pulls out. Then you can remove the connection plugs on each injector and use external 12V at the plug. There are several good videos on You Tube how to test them. You can test the injectors to see if they are leaking by pulling the rail and leaving the injectors plugged into the connectors for each injector. Now have someone cycle the on/off switch inside the car. When the ignition is turned to on position it turns on the fuel pump to supply fuel to the rail. If on leaks-by, you will see it on the nozzle of the injector. At the end of the rail they have a fitting similar to the air valve on your tire (I don't remember it's name at the moment, think it's a Schrader valve). Depress it and it will leak down the gasoline (catch it with a cloth) pressure inside the rail. Recycle (turn on) the car ignition again (not start mode). It should re-pressure your rail. Now if you have a leaky injector you'll see it.

After you watch some of the You Tube videos, I can give you pin numbers of each wire to test them at the DME. If you have a volt meter when you can read on/off voltage.

Hope this helps.

Briscoe

 

Thanks very much for the detailed explanation Briscoe!

While you were typing that up, I was checking the compression....which is zero on Cyl#2 and explains the gas on the plug. So I have another issue that I will have to diagnose: burnt #2 exhaust valve, blown head gasket, or something on the bottom end.

sani

 

Sorry to hear brother. That's a bummer. I don't know if I wouldn't put a rebuilt engine in it, rather than go through all the trouble. Somebody did a terrific post on how to pull an R56. The most detailed account one could ever ask for.