Vtec not engageing properly

[HiHiVti]

I have an issue that only started in the last day or so...the problem is when I bring it up to 4,800 rpm it crosses over fine but the Gos back out of vtec as the rpm still rises up to the 6,800 when the inlets start sucking air that's works fine but it's still kind of dropping in and out of vtec? Also about 2 days ago the fuel light came on and even with half a tank it still won't go off ... Would this be a fuel issue

[HiHiVti]

Cleaned out the solonoid a lot of dirt , done the gasket around it and changed the oil .... 😎 she's kicking in nicely again , thanks lads

[HiHiVti]

But this vtec is disengaging with throttle fully opened?

[noodels]

could check iabs working as they should,

http://cars.homenetcs.co.uk/honda-civic-mb6/checking-iabs.htm

battery + also unplug/reconnect  ecu,

maybe the vtec earth at the plug there.

other than that

[KiNK43]

Sure your sure it's dropping out of vtec? Not stuttering due to some other problem maybe ignition related???

[HiHiVti]

I was thinking maybe it was an ignition issue? But because it's inly happening while its in vtec stage and working perfect under 4,800 ??? Thanks for that link noodles in going to check that now

[Krzys]

Has it got enough oil in? As if it's low then the ECU will disengage it to protect the motor.

[JK1245]

Had a similar-ish problem on an Accord. You could hear Vtec engage, but power wouldn't change and then all of a sudden it would, but then it would drop again. Turned out the injectors had become clogged because of years of running it on really low fuel. Could try a £7 bottle of injector cleaner and see if that helps at all?

[Krzys]

Wouldn't it also do it if the oil had a low psi due to a dirty filter or the wrong viscosity of oil?

Not sure about the viscosity of oil but certainly low oil pressure would stop it as well.

[HiHiVti]

Tried that injector cleaner with a full tank of petrol and left it run its corse but still no joy now the vtec cross over at 4,800 rpm is completely gone , I'm thinking it's the solinoid

[HiHiVti]

I heard that it could be a build up of oil in the solinoid and also disconnecting the battery sometimes gets the vtec working again if all fails Im out of options only to sent it to a mechanic but my mechanic hansent a clue on how a vtec system works