Vtec cutting power too early

[EG6-NOVA]

Howzit Gents

I am new to the forum and would like some assistance from you fellaz.

I have a Civic Vtec Esi Engine Series D16z6 and when I read up on the car apparently I ought to be able to at least redline at 8000 rpm while the Vtec system kicks in at 5500 rpm contrary to what I read my car seems to have the vtec system kick in a 3500 and cut out at 5500rpm any ideas what could be causing this and how can I remedy that problem.

Your assistance will be highly appreciated.

JDM for LIFE!!

 

[TokyoSkies]

VTEC should engage at 4800-5500 rpm (depending on engine), and your redline is generally 7500 rpm. As far as disengaging, how do you know it's disengaging that early? Is it audibly different at that rpm range?

 

[EG2 LX]

I'm sorry but whoever told you a D16Z6 revs out to 8000 is dumb. You'd blow that motor they aren't ment for that high rpms. Maybe 7400..not 8k though

 

[reg_lus]

If u can redline at 8000 rpm, ur ecu have been tethered. No stock car can go up to 8k rpm. Majority of the z6 vtec
engage at 4800 rpm. And as far as I know stock cut out is at 7200 rpm

 

[EG6-NOVA]

Fair enough gents I understand about the 8000rpm issue
Lets put that aside... I would really like to know why my engine cuts out at 5000rpm as opposed to 7500rpm
Any troubleshooting suggestions?

Thanks

 

[AllegraSwed]

Can you add some more verges in it?

 

[EG6-NOVA]

Can you add some more verges in it?

Nope it totally cuts out and jerks

 

[obracer12]

how can you tell it is disengaging?

Once you reach the 6k+ range the engine tone and speed pick up so rapidly it is just engine noise at that point. With a single cam the engagement is weak to begin with.

How to test if Vtec engagement is lapsing:

Get a non-invasive (no wire cutting) current/voltage lamp, Connect the positive to the yellow/green wire that goes to the solenoid and the negative to the oil pressure sensor ground wire. Mount the bulb close to the windshield with the hood closed (you may need long leads. and take the car for a drive. When vtec engages, the lamp will light. For any reason if the lamp should go out there may be an issue with your solenoid or oil pressure.

This is just an indicator of the load to and from the solenoid. if you are receiving functional tests then the issue may be in 2 places; your head (you'll see it with every gear head, i.e. boost for 5 months think it's great then the urge to turn it up because "the car isn't fast anymore.") or the pressure/filter screen may have a slight clog.

 

[reg_lus]

does it smells bad? and do you feel like you're losing power just driving regularly? might be a clogged catalytic converter if you're using a stock cat?