Carbon Build-Up On Injectors

[tony0000]

Hi. I had to replace the fuel injectors on my low mileage 135i (N54) because of carbon build-up. Going forward, how can I lower the risk of this happening again? Any suggestions? Additives?

Thanks,

Tony

[MarcoZandrini]

What brand/s if gasoline do you buy? How does the engine perform? Does the engine consume oil?

[dworthy]

+1

I am thinking a lot of short trips, and low rev's out of the motor can carbon up an engine.

[tony0000]

Hi. Thanks for your response. I don't buy any particular brand of gasoline (but I always use the highest octane at the pump). The engine performs well and doesn't consume oil fast (I change/add oil according to schedule). There was a small idling issue, but I think that because of the build-up.

[shadowpuck]

does it consume oil, and what schedule are you using for maintenance?
also, what is your driving like with this vehicle - short trips? weekends only, etc?

[tony0000]

+1

I am thinking a lot of short trips, and low rev's out of the motor can carbon up an engine.

Yeah, I'm sure that's part of it. I confess to a having made a high proportion of short trips with the (obviously mistaken) idea that keeping the mileage low would be good for the car. I'm now taking it more frequently on longer highway jaunts. Gas bill is going up, but better than new injectors!

[tony0000]

does it consume oil, and what schedule are you using for maintenance?
also, what is your driving like with this vehicle - short trips? weekends only, etc?

I do a 10 minute drive to work a couple of days a week and I do a 5 minute drive to the gym a few days a week. I also do about 3 hours highway driving a week. Yeah, I going to have to use my wife's car for the gym! But I at a certain point, you just have to live your life . . . .

[pbonsalb]

A lot of N54s have had some or all injectors replaced. This is anecdotal, but I bought an 08 E61 535xi as a CPO with 30k miles in January 2011. I ran only Mobil 93 pump gas. My wife mostly drove the car but I put a JB4 on it and floored it when I drove it. Mostly 2ndary roads and highway. 155 was as fast as I drove it. Have it to a friend a couple of years ago but I still maintain it. 155k miles now. I did pull the injectors years ago when doing the valve cover gasket and they were not all the same index so at some point early in its life when it was under warranty, a few were replaced. I did all the work myself from 2014 on and did not replace any.

Drive it any enjoy it.

[tony0000]

A lot of N54s have had some or all injectors replaced. This is anecdotal, but I bought an 08 E61 535xi as a CPO with 30k miles in January 2011. I ran only Mobil 93 pump gas. My wife mostly drove the car but I put a JB4 on it and floored it when I drove it. Mostly 2ndary roads and highway. 155 was as fast as I drove it. Have it to a friend a couple of years ago but I still maintain it. 155k miles now. I did pull the injectors years ago when doing the valve cover gasket and they were not all the same index so at some point early in its life when it was under warranty, a few were replaced. I did all the work myself from 2014 on and did not replace any.

Drive it any enjoy it.

Yeah, I think that "Drive and enjoy it" is the moral of the story. When I bought my '08 135i last year, it had only 34k on it, which seems very low. Wanted to keep it like that, but I think I am going to be taking a lot more fast-lane joy rides. Still I wonder if any additives might help . . . .

[shadowpuck]

absent of any other info, so, just general/random recommendations/guessing - i recommend driving the vehicle so that it completes a warm up cycle - full cold to full warm and then at full operating temp for more than a couple of miles or so.

i also do not do much driving anymore since i no longer have to go into the office for any reason. dropped my yearly driving by 80%, at least.
so, i've been making sure i do a lap, as i call it, where i let the car (an '03 330 zhp or a Jetta TDi) warm up completely, then i give it a few runs on a highway lap, then i run my errand or whatever. i tend to pay more attention to this during the winter.

i've tended to avoid almost all additives simply because most don't really help - they don't hurt, but they do cost extra for little proven results.

i have heard folks i trust recommend techron and/or one of the lucas product (i think it was their injector cleaner/top end fluid) but i've had little to no personal experience with either.

on my street driven cars, i run top tier fuel and make sure they are driven - bmws (heck, most modern cars) do not like sitting.

[tony0000]

absent of any other info, so, just general/random recommendations/guessing - i recommend driving the vehicle so that it completes a warm up cycle - full cold to full warm and then at full operating temp for more than a couple of miles or so.

i also do not do much driving anymore since i no longer have to go into the office for any reason. dropped my yearly driving by 80%, at least.
so, i've been making sure i do a lap, as i call it, where i let the car (an '03 330 zhp or a Jetta TDi) warm up completely, then i give it a few runs on a highway lap, then i run my errand or whatever. i tend to pay more attention to this during the winter.

i've tended to avoid almost all additives simply because most don't really help - they don't hurt, but they do cost extra for little proven results.

i have heard folks i trust recommend techron and/or one of the lucas product (i think it was their injector cleaner/top end fluid) but i've had little to no personal experience with either.

on my street driven cars, i run top tier fuel and make sure they are driven - bmws (heck, most modern cars) do not like sitting.

Good thoughts. Thanks for the advice!

[dworthy]

It takes an average of 10 minutes to fully warm up an engine. So just as some context, you have to drive the car hard once a month if you are doing short trips during the week. Look up "Italian Tune-up" and that's about what needs to happen to keep the carbon at bay.

[tony0000]

It takes an average of 10 minutes to fully warm up an engine. So just as some context, you have to drive the car hard once a month if you are doing short trips during the week. Look up "Italian Tune-up" and that's about what needs to happen to keep the carbon at bay.

Thanks. I appreciate the specificity of your response.