Mini Cooper Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
I've been noticing some bucking around 1500-1800 rpms. It doesn't matter which gear or mode I am in. It's a 2017 Cooper S with 55k miles and the only change from stock is a Dinan axle back exhaust. I only run 93 octane and the air filter is new. could it be the plugs?
 

·
Registered
Joined
·
16 Posts
First thing I'd do is give your sensors a clean (particularly mass airflow) and rule out any/all potentially malfunctioning sensors. Do you have access to a scan tool of any sort, even if it's just a smartphone app? It's possible it could be plugs, but without knowing more its also just as possible that it could be fuel filter or a number of things. with 55k miles I'd be hesitant to suggest HPFP, but stranger things have happened in the world of BMW.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
First thing I'd do is give your sensors a clean (particularly mass airflow) and rule out any/all potentially malfunctioning sensors. Do you have access to a scan tool of any sort, even if it's just a smartphone app? It's possible it could be plugs, but without knowing more its also just as possible that it could be fuel filter or a number of things. with 55k miles I'd be hesitant to suggest HPFP, but stranger things have happened in the world of BMW.
thanks for the suggestions Nick, I do have a scan tool, but I haven't had any error codes. What kind of info can I get from the scan tool? what is HPFP? The weather is supposed to be nice this weekend. I will try cleaning the sensors , I don't have a garage :(
 

·
Registered
Joined
·
16 Posts
thanks for the suggestions Nick, I do have a scan tool, but I haven't had any error codes. What kind of info can I get from the scan tool? what is HPFP? The weather is supposed to be nice this weekend. I will try cleaning the sensors , I don't have a garage :(
No worries, always good to check active codes and memory on your tool in case the car itself can point you in the right direction. HPFP is the high pressure fuel pump, it’s one of two fuel pumps (low pressure is the other). Is your area / region etc known for having potentially dirty fuel?

Either way, you probably have the best idea about what the car is doing right now having driven it and experienced it. If you believe it’s plugs, it’s worth a quick look if you have the tools so wouldn’t hurt to pull them out and inspect. Don’t be surprised if they are fine though, because I think a plugs issue would also have symptoms in other parts of the rev range, not just in the 1500-1800 range.

The engine obvs needs spark, fuel and air and one or more aren’t perfect right now causing the bucking. If you can rule out spark and air problems, commonly being dirty plugs and dirty sensors, then at least you know it’s worth digging deeper and going through the longer process of trying to diagnose a fuel related issue.

In all honesty it’s probably not HPFP if you’ve got no codes but a quick look at the fuel filter might be worth the time.

it’s quite normal for the scan tool to not do all the diagnostic work for you, so don’t be alarmed that the car hasn’t even identified an issue yet.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #5
No worries, always good to check active codes and memory on your tool in case the car itself can point you in the right direction. HPFP is the high pressure fuel pump, it’s one of two fuel pumps (low pressure is the other). Is your area / region etc known for having potentially dirty fuel?

Either way, you probably have the best idea about what the car is doing right now having driven it and experienced it. If you believe it’s plugs, it’s worth a quick look if you have the tools so wouldn’t hurt to pull them out and inspect. Don’t be surprised if they are fine though, because I think a plugs issue would also have symptoms in other parts of the rev range, not just in the 1500-1800 range.

The engine obvs needs spark, fuel and air and one or more aren’t perfect right now causing the bucking. If you can rule out spark and air problems, commonly being dirty plugs and dirty sensors, then at least you know it’s worth digging deeper and going through the longer process of trying to diagnose a fuel related issue.

In all honesty it’s probably not HPFP if you’ve got no codes but a quick look at the fuel filter might be worth the time.

it’s quite normal for the scan tool to not do all the diagnostic work for you, so don’t be alarmed that the car hasn’t even identified an issue yet.
thanks for your thoughts NIck. I will continue troubleshooting as I have time. This is not a major issue for me now. just a little annoying. I'll post anything I discover.
 
1 - 5 of 5 Posts
Top