RB25NEO Timing Issue & IACV Issue

Discuss the RB20, RB25 and RB26 series engines.
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TimTurboZ
Posts: 663
Joined: Mon Oct 06, 2008 8:59 pm
Car: 95 S14 w/RBXX... 65' Mustang GT
Location: Sacramento, CA

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I got my NEO running today and it was idling at 2200rpms, adjusting the CAS didn't help much I maxed it out and it was still on the 6th crank mark (30* oppose to 15*) I figure with my lower CR pistons and premium in the tank it was ok to run. I pulled the plug off my IACV and the idle dropped to 1100. After it warms up it idles at 900. I assume the vacuum function of the IACV still is working because the car runs pretty much perfect beside the high timing.

I set the #1 piston to TDC and crank marks lined up perfect. I know for a FACT I set the timing/tensioner correctly when I put the motor together so don't bother telling me to double check it :slap:

I'm not sure what the function of the electronic portion of the IACV does. I assume I may need a new CAS.

Lastly if I have a poor signal from my MAF could it affect the timing?

Thx Tim


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TimTurboZ
Posts: 663
Joined: Mon Oct 06, 2008 8:59 pm
Car: 95 S14 w/RBXX... 65' Mustang GT
Location: Sacramento, CA

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I realized my variable valve timing may affect the timing, maybe it could be compensating for the IACV signal not going to the ECU...I have no clue how it works on the NEO's besides it's continuous from idle to redline. Car does feel pretty smooth

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TimTurboZ
Posts: 663
Joined: Mon Oct 06, 2008 8:59 pm
Car: 95 S14 w/RBXX... 65' Mustang GT
Location: Sacramento, CA

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If ANYONE has any Info about the NEO and my issue I'd appreciate it :)

Once I get Nistune it won't be an issue but it'd be nice to have it running basically OEM and perfect before I do any mods, could my 11lbs flywheel be a possible cause? My rb20 never had an issue tho

User avatar
TimTurboZ
Posts: 663
Joined: Mon Oct 06, 2008 8:59 pm
Car: 95 S14 w/RBXX... 65' Mustang GT
Location: Sacramento, CA

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Found this today

"Nissans system uses cam phasing to increase low to mid end engine torque.
Optimal valve opening and closure position for a given duration is different for every RPM and load combination, NCVS gives the engine the ability to take these factors into consideration and alters the timing accordingly. This is done using an electronic solenoid which adjusts the rotation of the cam by a maximum of 20 degrees, the solenoid is controlled by the engines ECU."

I guess I can unplug the solenoid and see if my timing is normal. I'm just not sure on how it's all suppose to be stock since theres no info online really :rolleyes:


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