Injector failure?

Jimmy Brooks · Mar 24, 2024

Hey guys, currently chasing a misfire issue with my parents discovery 5 (3.0L SCV6). The issue started with the car making a bucking sensation when accelerating up hill under moderate (3.5k-4k rpm) and has slowly gotten worse over time. The issue always seems to exist when the car is under load. I haven’t gotten the car to shut down a cylinder yet but it did finally throw codes. Unfortunately my IID tool is locked to my LR4 so I had to take it to O’Rielly to check the codes. Here is what was stored. Unfortunately they are only basic codes, not specific ones. Based off the behavior I’m thinking it’s injector, however I will swap a plug and a coil before going to the injector. Anyone experienced anything similar on their SCV6?

ftillier · Mar 24, 2024

Slightly off topic, but I thought the IID Tool could read codes without having to be bound to the vehicle, but not clear them or change settings?

jlglr4 · Mar 24, 2024

Seems like fuel delivery is a logical place to start looking since it’s worse under load. I’d probably be thinking fuel pump before injector, but could be either. Too bad you can’t see fuel rail pressure or fuel trims.

I also thought the gap tool could be used as a code reader on other LRs even though it’s locked, but never tried it.

Jimmy Brooks · Mar 24, 2024

Wow I did not know that but you guys are totally right. Again tho they are still pretty unspecific all suggesting the same thing but that makes it a lot easier because now I can swap the coil and plug with another cylinder and see if the issue follows. Also you can clear codes, you just can’t enable and disable features, and reajust height settings on air suspension but you can do all of the things under service and test and you can see all live values. Thanks, massive help!

Jimmy Brooks · Mar 24, 2024

Swapped the coil and the spark plug and cleared the codes to see if the misfire would follow but strangely enough the issue is now gone… drove the car 30ish miles today with frequent moderate accelerations and I couldn’t recreate the issue. It’s really weird but the issue was also routinely and very consistent with the correct input so I’m pretty stumped. I did put a bit of BG44k in the fuel tank a while back but the issue continued to get worse and it’s probably been filled up 4-5 times since then. Could that and a simple code clear have solved the issue? Just pretty confused…

Longtrail · Mar 25, 2024

Could it be some sort of electrical gremlin whereby re-seating, moving, etc. has caused the fault to disappear? At a stretch I could imagine moving the coil and plug could reestablish a better ground? It's weird!

Injector failure?

Jimmy Brooks

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