Hey everyone… been having some trouble with my engine misfiring and the catalytic converters going bad. I’ve already replaced the cats, upstream and downstream sensors, spark plugs, and coil packs. Only thing I haven’t done yet is the injectors. I’m a diesel mechanic, so I don’t know much about gas engines. How many injectors does this engine actually have? I’ve heard 6 from some people, but others say it’s 12. If there are 12, where would the other 6 even be located?
The 2.7 Ecoboost uses a dual injector system. There are 6 direct injectors under the intake manifold and 6 port injectors. If you have a good scan tool, you can check the freeze frame data from when the misfires happen. The engine starts on direct injectors, idles on port injectors, then switches to both at certain points, and runs only on direct injectors under high load. I usually force the engine to run on just the port injectors or just the direct injectors during a full throttle sweep to figure out which set is causing misfires. But you’ll need a decent scanner to do that.
@Maria
I’m getting these fuel system readings:
FUELSYSA_B1: 0%
FUELSYSB_B1: 100%
FUELSYSA_B2: 0%
FUELSYSB_B2: 100%
Tyler said:
@Maria
I’m getting these fuel system readings:
FUELSYSA_B1: 0%
FUELSYSB_B1: 100%
FUELSYSA_B2: 0%
FUELSYSB_B2: 100%
If those readings are at idle, that means the fuel system B is your port injectors working at 100%.
@Maria
Those numbers don’t change at all, even when I rev the engine or let it idle.
Tyler said:
@Maria
Those numbers don’t change at all, even when I rev the engine or let it idle.
Might need to have someone drive while you watch the scan tool readings in real-time.
@Maria
Haha, I actually thought about mounting the scanner in my phone holder for the ride home. I’m used to TEXA software for diesel trucks, so these OBD2 scanners are new to me. Are there any other fuel values I should be watching for misfire issues?
@Tyler
I’d check the low-side fuel pressure actual vs what the PCM wants, same for the high-pressure rail. If you can, try commanding the engine to run on either just port injectors or just direct injectors—that’ll tell you which system is giving you trouble.
Could be the MAF sensor acting up. Any check engine lights?
Chloe said:
Could be the MAF sensor acting up. Any check engine lights?
Only showing misfires on cylinder 2 and 5.