here is the setup

p72 ecu
hondata s200 w/ boost TUNED
datalogging
rom editor

VTEC will not engage when specified

wen i datalog it says i get vtec spool at the correct time but no vtec pressure so i did the whole flow chart in the helms and found my VTEC solenoid and pressure sensor are both good.

When I unplug my vtec pressure sensor with the P72 ECU I get no code 22 like i should. But when i plug in my P5P (stock ECU) back in (runs like crap with 450ccs) and unplug the same sensor i get the code 22. The OBD1 P72 is from a GSR and they do use vtec pressure sensors just like an h22a4

What gives I dynoed the other day and great power up to around 5000-5500 rpms (vtec set at 5100) and the power just drops and the AF ratio just gets pig rich from switching into the high cam fuel maps and not engageing VTEC. I have open dump from the wastegate so when VTEC hits in a dyno shop it is VERY loud and i couldnt hear crap.

What could be wrong?

edit: i went a step further into the helms and checked the mid rockers for free operation and the lost motion assemblies,


that tell me what i already know that i am not stuck in vtec, but to go to the next step i need to check and see if vtec engages when i hook up the air pressure to the access hole in the front and plug the air relief valve like in the helms and see if the pins lock the mid rocker in. But i have no air compressor is there any other way to check if they are locking in? But that still wont explain the vtec pressure sensor not throwing a code when it should.

I even lowered the VTEC to 3000 and checked to see if i could hear VTEC then and nothing.

One more question what provides oil to the pistons that engage the VTEC rocker? I am not clear

 

First, oil is always there, but when vtec kicks in and the solenid opens, it allows the oil to flow into the rockers .

second, to check if the mechanical part of vtec is working you can bypass 12v. to the solenoid to see if it works, then you could do it with the engine running(at like 2500 rpms or 50psi) and do the same to see if you hear the switch over.
You could also check vtec oil pressure when you bypass the solenoid

third, if everything above checks, then your problem is most likely electrical or its hondata.

 

who put the head together i had that problem
after i fix my bent valves

my dum as put the lose motion device upside down(hey who knew the pointing side goes up)i figure that out my self a year later!

my friend had a car that vtec didn t engage either
but his was because it was looseing oil pressure(a oil plug was missing) rite by the intake cam next to the dist.

 

try changing the spool filters, they could be clogged.

 

It sound like the ECU or Hondata If everything else is OK.
If you open the ECU and have an ohm meter check all the resistors capacitors, ect. if the resistance is good on all of them
here's a site that might help http://www.hondaswap.com/~pills/autotomanual.html

 

part ur car
rev it over 4k rpm then connect the vtec solinoid wire to the battery postive if the engine tone doesn t change (bough)then vtec is not working (also u should hear the solinoid click.)

if the solinoid clicks but u don t get an engine tone change(bough)
u have oiling problems
put a oil pressure gauge to the from of the head by the header
when vtec is engage u get about 15 psi of pressure.