Code Help!

[Mike.]

Hey guys,

I randomly get the 118001 and 118101 codes...I'm at a loss for what to check because it happens randomly..could go for 2 months with nothing, it pops on (no performance loss) and I clear the code and go about my day. There is no pattern that I can find, Maybe its the intakes?

I run E30 flex fuel tube by Alpine, and, I have MST intakes. could it be the intakes? I had a shadow code of these before I switched to the flex fuel tune, but now the CEL comes up on the dash.

I can clean the MAF and make sure its seated correctly...any ideas?

[TheMaster1971NL]

I think the Mixture is to lean.

[Mike.]

Originally Posted by TheMaster1971NL

I think the Mixture is to lean.

i would agree but a quick search states the intakes may throw this code. If this was tune related,wouldn't it come on all the time?

[Fred E]

Originally Posted by Mike.

i would agree but a quick search states the intakes may throw this code. If this was tune related,wouldn't it come on all the time?

Not necessarily. There could be a lot of factors that cause the mixture to be lean enough for long enough to trigger the code, including certain types of driving events or even ambient air temperatures. If the tune has not been adjusted properly to account for the intakes, the code will continue to randomly show up.

[Mike.]

Originally Posted by Fred E

Not necessarily. There could be a lot of factors that cause the mixture to be lean enough for long enough to trigger the code, including certain types of driving events or even ambient air temperatures. If the tune has not been adjusted properly to account for the intakes, the code will continue to randomly show up.

Originally Posted by Fred E

Not necessarily. There could be a lot of factors that cause the mixture to be lean enough for long enough to trigger the code, including certain types of driving events or even ambient air temperatures. If the tune has not been adjusted properly to account for the intakes, the code will continue to randomly show up.

Interesting. I had a hunch it might have to do with the air temps. I feel like when it's hot and humid and the car bucks it'll ding the CEL. I guess I can speak to my tuner and see what he has to say too.

[TopJimmy]

Originally Posted by Mike.

Interesting. I had a hunch it might have to do with the air temps. I feel like when it's hot and humid and the car bucks it'll ding the CEL. I guess I can speak to my tuner and see what he has to say too.

I googled and found this BMW Notice on those 2 codes. Looks like the fix I found involves a SW update. I would not do this update for fear of locking the DME, and would simply clear the codes out with BM3.

https://static.nhtsa.gov/odi/tsbs/20...47072-9999.pdf

[Mike.]

Originally Posted by TopJimmy

I googled and found this BMW Notice on those 2 codes. Looks like the fix I found involves a SW update. I would not do this update for fear of locking the DME, and would simply clear the codes out with BM3.

https://static.nhtsa.gov/odi/tsbs/20...47072-9999.pdf

of course I get the prissy baby DME haha

I'm going to clean the MAF, and make sure everything is attached correctly and go from there I guess.

[Mike.]

going to bump this- i have isolated the incident to when i got WOT.

I am almost 100% sure its the intakes. Sucks cause I really loved the sound. Last bit of testing is doing a log, which in my only achilles heel because my alpine tune does not come with logging software, so I think my only option is MHD logging.

[AlmondJayRoM3]

Originally Posted by Mike.

going to bump this- i have isolated the incident to when i got WOT.

I am almost 100% sure its the intakes. Sucks cause I really loved the sound. Last bit of testing is doing a log, which in my only achilles heel because my alpine tune does not come with logging software, so I think my only option is MHD logging.

Without going too in depth, it could be either a loose fitting somewhere allowing unmetered air to get sucked in the car (i.e. vacuum leak) the intake, or the tune or some combination of the three. Need to eliminate any intake leaks and data log to be sure.

Aftermarket intakes tend to cause CELs because of variations in size. If the size of tube that the MAF sensor goes in is different than stock, then you are effectively changing the airflow/volume ratio. With a larger size tube the MAF sensor will measure a lower velocity for an equal volume of air. This will be caught by the O2 sensor lambda and fuel trim adjusts accordingly to maintain target air:fuel ratio. The CEL will trigger when the fuel trim goes out of specification and will throw a lean code (or rich if the intake constricts flow, but not as common).

Ideally the tuner will account for this but it's not always the case and will vary based on which intake is used.

[Mike.]

Originally Posted by AlmondJayRoM3

Without going too in depth, it could be either a loose fitting somewhere allowing unmetered air to get sucked in the car (i.e. vacuum leak) the intake, or the tune or some combination of the three. Need to eliminate any intake leaks and data log to be sure.

Aftermarket intakes tend to cause CELs because of variations in size. If the size of tube that the MAF sensor goes in is different than stock, then you are effectively changing the airflow/volume ratio. With a larger size tube the MAF sensor will measure a lower velocity for an equal volume of air. This will be caught by the O2 sensor lambda and fuel trim adjusts accordingly to maintain target air:fuel ratio. The CEL will trigger when the fuel trim goes out of specification and will throw a lean code (or rich if the intake constricts flow, but not as common).

Ideally the tuner will account for this but it's not always the case and will vary based on which intake is used.

thanks for this info.

So far the connections look snug. I'm going to check over that nd clean my MAF sensors. The intake is an MST open intake, I think it may be a combination of the tune/intake. I downloaded MHD so hopefully we can figure this out with a log.

[TopJimmy]

Originally Posted by Mike.

thanks for this info.

So far the connections look snug. I'm going to check over that nd clean my MAF sensors. The intake is an MST open intake, I think it may be a combination of the tune/intake. I downloaded MHD so hopefully we can figure this out with a log.

Mike, I got MAF Implausibility errors with my MST when logging WOT for Paul. When I switched back to stock boxes it stopped. Paul said I could ignore or clear those codes and not worry, and that stock boxes were better for IATs. I went back to stock because I race for times, but for street the MSTs would have stayed on since they sound good. As long as the errors didn't hurt anything…

[slaughter.mode]

Have you smoke tested your intakes? Cleaning the MAF helps. A lot of intakes place the MAF in a position to give these codes. My AFE & Dinan did not but I haven't ventured into that brand.

[Mike.]

Originally Posted by TopJimmy

Mike, I got MAF Implausibility errors with my MST when logging WOT for Paul. When I switched back to stock boxes it stopped. Paul said I could ignore or clear those codes and not worry, and that stock boxes were better for IATs. I went back to stock because I race for times, but for street the MSTs would have stayed on since they sound good. As long as the errors didn't hurt anything…

I remember you saying this, and that's what i thought could be the problem. The piece is coming tomorrow to log so we will see. If this is tune related I may jump ship back to RK tunes.

Originally Posted by f82.959

Have you smoke tested your intakes? Cleaning the MAF helps. A lot of intakes place the MAF in a position to give these codes. My AFE & Dinan did not but I haven't ventured into that brand.

I have not, I have to look for a kit I have never done that before

[Mike.]

edit-getting a new log. the one I uploaded made no sense

[Mike.]

a little lean perhaps? https://datazap.me/u/mike11940/log-1...10-17-23-24-25

what do you all think

[Dasky_spas]

What was the end result? I thought 180001 and 180101 were cats operating below efficiency, or no cats.

[Mike.]

We messed around the tune and it went away. Don’t have a definitive answer. Sometimes if I mess up the e45 mixture it will come back, but I don’t think I’ve seen it for about a year.