d15b p28 how does this work?

[puttockc]

I am a noob

My car has a p28 ecu, not sure if its modded or not, cannot figure out how to tell

I am getting 18 mpg

would this be caused just by having a d15b and a p28 together? I plugged in one of those computer and it says no codes are registering and the O2 sensor has 4 wires coming off it, it looks kinda jerry-rigged going into the ecu but I have never seen another ecu so... yeah

the second part of the question is how can I tell for sure whether my d15b is the kind with the multiple vtec stage or the single stage

someone said that if I had the wrong ecu for the multiple vtec would only engage the more powerful stage

my engine tends to engage vtec at 5500 rpm and feels powerful as hell, but the only other car I have ever driven flat out is a diesel jetta

so.. how can I tell what I actually have running and would having a p28 in combo with a d15b (either kind) cause 18mpg fuel economy


Thanks in Advance

-Clueless Noob

 

[AHHVTEC]

how many vtec solenoids does it have

 

[puttockc]

I have no Idea how to tell,

I know it has one connection which if unplugged would cause I power cut at 5500rpm which I assume disconnects vtec

 

[AHHVTEC]

well if its a multi stage vtec it will have more than one vtec solenoids