Timing adjustment

[NISMO_RB25]

Please excuse my ignorance with this question.

I have never had to adjust or check timing before on any car. My RB25 seems to be running ok, but I want to double check before I do any further modifications.

Does anyone have a good link they can post on how to do it properly and what type of gun to use? Or does anyone want to write something up on it?

Thanks guys.

[Joe]

You need an inductive timing light, the only way to do it that i know of is to remove the coil pack cover, on the #1 cylinder (closest to radiator) the big white wire. clip the timing light clamp around that. (im pretty sure its that wire, if it dosent work try a diffrent one. there is no harm done if you use the wrong one)

disconnect the TPS sensor, dont know why but i think it has to do with the spark control that the ECU uses.

point the light down at the crank pulley, i B E L I V E the crank pulley mark should be at the 3rd mark from the left. that would be 15 degrees BTDC.

anyone verify this? its been a while for the RB since ive timed one. they are a ***** to time right. i never got mine at a perfect 15 degrees.

[GTR Shop]

Pull the TPS plug before you go top time it.

End of the day, set upr base and mark it.

Take the car to a dyno and dial in timing 1 deg at a time until you get it to det (prob ~5500-6000rpm)The pull it back 1.5 deg.

Timing makes a big diff in power on RBs.We've got an 20kw atw on a RB20 and 12kw atw on a RB25 (higher comp)

[NISMO_RB25]

Thanks guys, I really appreciate it.

[goofynick6]

I was told by someone on here 2 things:

Don't disconnect the TPS

Timing is 20 deg's at idle.

What's true?

Nick

[fly240]

I need to check on my timing too. If anyone has any experience on rb timimg please let me know too.

[Joe]

I was told by someone on here 2 things:

Don't disconnect the TPS

Timing is 20 deg's at idle.

What's true?

Nick

i know you disconnect the TPS, and i know base timing is 15 BTDC. 20 is too far advanced.

[goofynick6]

QUOTED BY CARL H in another post:

with the rb20 you do NOT need to disconnect the tps, this only sends the ecu into some weird mode (possibly limp home mode).you first need to adjust the idle, and thats controled by the AAC valve that is on the back of the intake plenum.once that has been lowered change the timing to 15 degrees btdc, that will be 3 marks from the 0 degree mark as it is increments of 5.

Nick

[vududoc]

Base timing valuesWarm up carDisconnect AAC RPM should be 750 +/- 50 rpm set by idle screw15* BTDC....more aggressive @20*BTDCTPS .45-.5 at idle Better results .45vplugs 1.1mm better results yeilded @ .8mm

[Joe]

QUOTED BY CARL H in another post:

with the rb20 you do NOT need to disconnect the tps, this only sends the ecu into some weird mode (possibly limp home mode).you first need to adjust the idle, and thats controled by the AAC valve that is on the back of the intake plenum.once that has been lowered change the timing to 15 degrees btdc, that will be 3 marks from the 0 degree mark as it is increments of 5.

Nick

im not gonna sit here an argue, just wait till you try to time it with the TPS connected. the timing jumps around because thats what its supposed to do. when the ECU is in limp mode its running a base timing. thats what you are setting.

[goofynick6]

I'm not saying it's right or not, I'm just quoting him in case he had some good info. I think unplugging the AAC is right, because I have the RB20DE (not T) manual, and it doesn't mention the TPS at all with timing, but does mention unplugging the AAC.

Nick

[Joe]

*shrugs* ive tried to time a few RB's and none of them will with the TPS plugged in.

[WDRacing]

I've done it both ways, tps connected and disconnected. But it makes sense to me to disconnect the TPS and set the AAC idle for 750. I used 20* BTDC only cause we ran 100 octane gas in Japan. 15 is all you want with anything in the low 90's.

I don't think the AAC valve has to stay disconnected, it just needs to set to 750 for timing at idle.

I love when guys have a jacked up idle but try to set base timing anyway...lol.

Brian

[fly240]

Hi, sorry to be so dump, but i have never done timing before. Can any body give me a full definition of the (TPS) is?. Thank you

[goofynick6]

TPS = Throttle Positioning Sensor and it is located on the side of the throttlebody. It senses how much load is on the engine.

Nick

[fly240]

ok, but i think on my throttle, i have the plug but no wire, will that be ok on the timing. thank you

[NISMO_RB25]

I had a friend help me check it today. It is a little past the third mark from the Red mark, which I believe to be about 16-17. I am comfortable with that, but I have a question.

Now that I know how to check it. How would you change the timing?

[IvoryJ30t]

moving the cas.

clockwise-retard counterclockwise-advance

[NISMO_RB25]

Thank you.

Can you do it while the car is running?

[IvoryJ30t]

yes

[Ender_Zero]

so where is the Crank Angle Sensor on these motors?

[goofynick6]

Right on the front, hooked to the driver's side cam.

Nick