RB26dett Idle RPM

Nissan Skyline GT-R idle rpm . Ignition timing is 20 degrees BTDC

An RB26dett has a fairly high idle. Nissan sets it at 950 rpm. On the tach it normally sits right at 1000 rpms, and should be very smooth if the car is stock. 

2568 cc also called 2.6 liters.

Ignition timing is set at 20 degrees BTDC at 950 rpm.

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Rough Idle or High Idle : Nissan Skyline GT-R : RB26

An RB26 should idle smoothly at around 1000 rpm on the tach. There should really be little vibration, or noise, other than what a 25,27 year old solid lifter engine makes.  Which in reality is pretty loud with the hood open.

R32 GT-R Speedometer in miles per hour

Most of the time, if you hear a noise, that sounds like a really bad lifter, it is normally the bottom end on an RB. However, troubleshooting that is a different post.

Troubleshooting a Rough or High Idle Nissan Skyline GT-R

• Observation is key

• It is important to have a look at what a car is doing. Open the hood, look for anything obvious. 

• Once you have had a cursory look under the, hood, make sure you have gasoline( had this happen to me recently), make sure the fuel pump seems like it is running, no crazy amount of smoke out the exhaust, onto the next step

1/2 a tank of gasoline

• MAF

• Are they plugged in?
• Do the hoses look OK? 
• Give them a bit of a tap with your hand, does the idle rpm change?
• If yes, then proceed to MAF troubleshooting page. 

1. 

   MAF with HKS air filters

• Vacuum leak
• There are lots of spots to have a vacuum/boost leak. 
• Large intercooler hoses
• There are the top intercooler hoses that are visible, plus the ones that run though the fenders to the intercooler. If these come off the car will idle rough and spit black smoke out of the exhaust. 
• Around the fuel injectors
• The lower injector bushings can get crispy and shrink over the years. They are rubber and get hot. Sometimes just giving the injectors a twist will reveal an issue. 
• Otherwise a can of brake parts cleaner or the like, sprayed at the injectors, and throttle bodies can reveal a vacuum leak. 
• A smoke test, or pressure test will not always show leaks depending on what side of the throttle bodies its on, and what you plug/disconnect. 
• Throttle plate adjustment
• Three sets of two throttle bodies
• Individual adjustment
• TPS adjustment
• If the car doesn't know it is at idle, you can have some idle instability. 
• It should be appropriately 0.5 v at idle
• It should be approximately 4 v at WOT
• IAC adjustment
• Idle Air Control
• AAC adjustment
• See below.

DO NOT CLEAN OEM THROTTLE BODIES, unless you have a sealer like Tomei Throttle coat to ensure sealing. If you clean the sticky mess off the inside, once you get it all back together, the idle will be high, with no real way to get it to idle lower.  That is without taking it all apart and adding something to seal up the blade edges.

The OEM paper gaskets are thin, and leak fairly easily. We like the Tomei gaskets, they are metal, and will not fail like the stock gaskets. There is one long gasket against the head, and one set of two for each side of the throttle plates, or 6 of them.

14035-05U10 - Long gasket head to balance chamber (these tear if you look at them wrong)

16175-05U70 - Gasket throttle bodies x 6. (one each side of throttle bodies)

We have used this Molykote Dry Film Lubricant to help seal and lubricate the throttle blades. It comes in a spray can. 

AAC Adjustment RB26dett Nissan Skyline GT-R

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