Hi folks

Sorry if this is covered elsewhere but a quick search didn't show anything...

My VTEC seems to have gone a bit "soft" over the weekend. There used to be a more pronounced change in engine noise and more performance, but now the change has become more mild to the point of being imperceptible some times.

Any ideas on what might be causing it? The oil is full and there are no error codes currently...

Thanks

TM

 

Getting use to it and going deaf?

Air filter clogged up?

Cat blocked?

 

Haha could be showing my age yes!!

Will check air filter - has a new "sports cat" from DMS about 6 months ago, guessing there is no easy way to find out if there's a problem with it? Pulling nicely and running smoothly lower down the revs...

Cheers

 

Is the engine at correct temperature?

 

I have found the differences in ambient temperature can also have an effect, as can the fuel you're running. Is it just the changeover that feels 'soft' or the big cam performance as a whole?

 

Depending on the previous history like regular oil changes the vtec filter can get partially blocked, also if the engine has had a flush can sometimes partially block the filter, not having the correct oil can effect the change over, but the simple ones are to make sure everything has reached temp on colder days

 

The car won't VTEC till its up to temperature, if its just in general the ECU learns your driving style and adjusts fuelling accordingly. Pull the ECU fuse (or disconnect the battery if you have the radio code) for 5 mins put it back start up and let it go through two cooling fan cycles, then take it out for a good thrash, it will re-learn its fuelling and give you the VTEC beans back.

As per Datona-Daves comment, make sure you have enough oil, low oil will stop the VTEC working and is extremely bad for the car, keep it topped up to the top X on the dipstick, each X = 100Ml.

 

I'd start with the basics, is your throttle opening fully (i.e. has the cable adjuster slipped ?)

 

Thanks guys. This was throughout a long journey so at the proper temperature, with full oil. Generally performance seems slower than usual, feels more like just an extension of the pre-vtec performance and it doesn't sound as good. I've got some good things to look at there:
-I've put a small amount of 10w synthetic in rather than 5w, which might not have been wise?
-The throttle link was pretty loose previously and is right on the end of the screw thread (i.e. can't tighten any more) - I might can check that as the world's easiest problem to fix.
-I'll look to see if next door's cat is living in my airbox or something
-Then there is the non-OEM 'sports cat'...
The car has done 89k so there's a chance some of my sensors are getting old too I guess?

Cheers!

R

 

Pop one of these into your oil, it will re-invigorate your floppy VTEC solenoid