Hello my friends, I have a problem with my civic I hope you can help me because I am a little lost, then there I have an mb3 swape b16b, my problem is that sometimes my car drives rich " 10 "in AFR alr that the And set to this range of 15.1, it sometimes drives well and suddenly, the car gets richer after it returns to normal. Idling while driving normally and even accelerating in any case, I have this problem.

Ideas?

sorry for my bad english i'm french

 

What engine management are you using?
Is the engine completely stock or is there something been done to it?
What Engine wire harness was used when the engine was swapped?
You need to provide at least this information to get some responses, otherwise it is only guessing what could be wrong.

 

What wideband are you using as well as what engine management system? (Hondata, AEM, ect.)

 

I have a very similar issue with my Engine, every once in a while after so many miles driven the AFR changes very rich during operation at all loads and rpm, I narrowed it down to my Map sensor because I noticed every time I simply unplug my Map sensor and plug it back in it magically fixes the issue and my AFR and tune is back to normal only after a few thousand miles it returns, I think I may have a faulty Hondata Map sensor, or a short in the wiring. Might be worth a try to check out the map sensor.

 

Datalog the MAP values when the engine performs poorly, unplug the MAP sensor, plug it back in, and datalog the MAP values again. Then compare the data and examine the differences.

 

Great idea! last night in boost I was very rich! in the 9's! but part throttle and idle remained fine, I didn't have my lap top because the battery died, I was bummed because I wanted to data log it. I usually drive around recording the data but my laptop battery drains fast.