CAT IVA (Intake Valve Actuator) Defined...Kind of

I'll be the first one in line beating on their doors

 

I have been a engine tech with carter and milton cat for 10 years, working on kcb(c13) bxs (first gen c15 accert) mxs (2nd c15) when they first came out. The definion of acert is Advanced Combustion Emissions Reduction Technology. In short it means a number of different systems or technologys (software, VVAs, 2 turbos, etc.) put together to meet EPA regulations starting back, I think in 98. Now, VVAs lower combustion ratios in cylinders when not needed, like going down hill or under low loads. They crack open the intake valve lower the combustion ratio. lower combustion ratio means less fuel, which means cooler cylinders and better mpg. How I found this this forum is I was looking for anyone that has been have problems with dropped intake valve with the VVAs(found nothing on cat site.) Backing off VVAs settings will cause problems, you will have a check engine light with codes of VVA not responding, etc. which will derate your engine. Messing with the setting may also cause valve and piston contact, internal engine damage is expensive for a experiment

 

My question to you is are the vva letting in combustion gases or clean cool air and if they are working properly they should help in lowering the egt

 

Clean air, on 04 acert(04-07) (bxs,mxs,nxs,kcb) engines there are no exhaust gases in the intake system, dual turbos are there for higher boost pressures to push more cooler air though the cylinders when both valve are open. Even if the piston does push some air back into the intake with the VVAs it would be clean air because the exhaust gas where pushed out on the exhaust stroke and valve over lap.

NOW, if you have a 07 acert(07-10,11)on-highway engine(sdp,lee,c7s), Cat did not run "EGR" they used there own system CGI, clean gas induction. they pulled exhaust gas after the dpf diesel particulate filter. Now you might have some black in your intake pipes but if you have alot, you might have a bad DPF pushing raw exhaust gas back into your intake. VVAs have nothing to do with CGI and it is a different system.

 

I set to .040 never have problems because there still working just not as much so not as much compression lost.

 

I eliminated mine cut the wires. Makes less boost, same power, way cleaner oil samples.

 

Partially. The CO2 part!

 

Which wires did you cut and did you get check engine light.

 

Yes I did get a check engine light. The guy who tuned my ecm took care of all of that crap. Changed injection timing and no resistor on temp wire either. Took Care of it all with his laptop in 5 min.

 

Can the VVAs be turned off with the ECM without cutting any wires or backing them off?