ok so i have a 90 crx si with a b16 swap the problem is when i get about 7200 rpms or around there it feels like vtec is cutting out. The oil is full just changed new fuel filter new injectors new plugs new cap new walbaro 255 fuel pump. Ecu is stock not running lean. cleaned the vtec solenoid. I am lost on what to do next any help will do thanks guys

 

check oil pressure? maybe you dont have enough to fully engage it? does it run just fine other than that?

 

and when you say 'vtec feels like its cutting out", does it sound like its turning off and on? or does it just make the WHOLE engine cut out? if the vtec solenoid was engaging/disengaging, you would hear the difference in engine tone, not the whole engine cutting out..

 

any CEL's??

 

right oil pressure is good. um feels like it gets under a load engine isnt missing or anything just looses power in that rpm range. No cels

 

hmmmm.... is your ignition timing right? if, for some reason, your dizzy came a lil loose, it may have advanced your timing, causing knock, which the knock sensor picks up, and then retards timing (a byproduct of which is losing power)..

thats just a wild speculation.. i would just check the ignition timing, and maybe test the knock sensor (if thats even possible)

 

good ideas but no i just redid the timing for that idea. knock sensor is new from honda when i swapped everything. it has not skipped a tooth on timing either. im really lost here

 

hmmmm.. maybe bad ECU? have you tried a spare one? i know you probably dont have one.. lol.. but its a thought... Bad ECU's do odd **** when going bad...

what has changed since this happened? like, what ALL have you replaced?

 

Did it ever work correctly?
With my friend's swap,They had given him an ECU for an automatic..

Under the top ECU cover it will say AT or MT on one of the circuit boards..

 

well, the ecu would not cause that to happen if it was for an auto.. i dont see how the maps for timing/fuel, etc. would cause the engine to be rude at 7,000+ rpm

but yeah.. he does have a point.. has it ALWAYS done this?

 

Well its a manual Ecu. And its weird I think it sounds the same but just loose power like it was disengaged or something. And sometimes it will Rev upto 8 just fine

 

ehhh... do you ACTUALLY HEAR vtec disengage? im sure you know the sound of it kicking in well... baaaaaaaaaaaaAAAAAAAHHHHHHHHHHHHH
^vtec on

does it sound like BAAAAAAAAAAAAAAAAAaaaaaaaaaaaaaaaaaaaaaaaAAAaaaAaa aaaaaaaaaa
^vtec off

hahahaha.. i know its an odd way to ask.. lol