Hey guys i have just started tuning my bolt on jdm b18cr and i have a problem with afr going lean after vtec. It only happens when i hit vtec and i go back to the low cam (cruising), before it engages vtec afr is around 14.6 to 15 but after vtec it will go to high 16 to low 17afr. I have tried new wide band o2 sensor, checked for vac leaks with no luck. I am tuning with crome free, Any questions or info i left out i will do my best to provide the info to the best of my knowledge. Any help is welcome and very appreciated thanks in advance.

 

Add fuel in vtec map?

 

This ^

Post a screenshot of your fuel maps

 

Hey man, glad to see someone else start to get into the self tuning realm, always good to see. Anyway, your problem is just that you are lacking fuel values in your High cam map. The solution to this is just to tweak your high cam fuel map to get things where you want them. Ideally an all motor stockish B18C likes high 12's low 13's at WOT in VTEC. As was said above, post a pic of your current fuel maps and some of us can help you easily figure out how much fuel to add. On a side note, I would stop going WOT with your current map immediately. Those are some very lean AFRs at WOT in VTEC and could easily cause damage with repetitive occurances.

 

its not lean until i come out of vtec. When im in vtec my afr is between 13 and 13.4 for wot vtec and low cam is a touch richer at wot. when im crusing before i hit vtec its at 14.0 to 14.8 depending on load. like i said only after getting into vtec does it do this it does not matter if im at partial throttle going into vtec or wot it will go lean, but as soon as i come to a stop the afr goes back to 14 to 14.5 at idle it is only lean in the first 5 columns. when i add fuel to the map in those areas its at like 11.0 to 11.3 on low cam but when i go into vtec and it switches back to the low cam the same lean condition happens. i checked timing which is good, swapped out ect sensor, and map sensor. i have the o2 completely disabled i have tried different fuel multipliers, less timing, not sure whats going on but im building a short block so this is just to learn on till i get that in the car. i am using crome and free log till i can get neptune and the demon rtp. thanks for the replies any other insight is very appreciated.

 

what fuel injectors do you have?are they clean?

 

You said that you have the O2 sensor completely disabled, do you have the closed loop operation disabled as well?

 

it has stock 240cc injectors and they should be clean. what do u mean disable closed loop, in the options for crome i disabled the o2 heater, and disabled oxygen sensor(open loop).

 

That's what I was referring to.

Where this is just a stock engine with stock injectors and bolt-ons. I would try enabling closed loop and see what happens during your closed loop operation. If it goes back to seeing stoich AFRs then you are missing something in your fuel maps in your open loop tune.

 

it does the same exact thing

 

just wanted to update the post i think crome was just buggy because i ended up picking up a demon rtp and neptune and dont have a single prob. before i got the neptune setup i tried making new maps with p30 and p72 base code to start ive taken tuned maps and work off them and it always did the same thing going into high rpm it would be fine but if i went back to crusing it would be very lean but before going into high rpm afr was where it was tuned for. ive made 4 or 5 base maps on neptune all run the car ok and i have 2 other tunes that are more than good for a daily but still tweaken them hear and there. Not any lean problems at all on any of the neptune maps. Thanks to everyone who offered a suggestion. SOLVED