GT-R Timing???

[GodziRRa]

Hello Guys!

I have a new actron timing light for my D.I.Y purposes. Today I tried playing with it using the small timimg loop. And to my surprise my timing was like 30 degrees! The last of the small timing lines to the right! I tried flipping the inductive sensor over but the results were the same... So confused.

If the timing was really 30 degrees will it have some ill effects with engine?? Is this what you call off timing? Sorry not that knowledgeable yet on our car yet. Maybe this is the source of my cold starting problem. I have a Jap mechanic taking care of it before, but we have parted ways for months so I'm totally clueless.

Well hope you can help me gurus. And a Happy and Blessed New Year to us all!

[GTR-Dad]

Be careful where you're picking up the signal. The loop at the back of the ignition harness is not a good spot to use. Better to either get a short plug wire and run it between #1 (front) coil and plug and put your pickup there OR put the pickup around the hot wire leading to #1 coil and push the pickup right up against the coil.

30 degrees advance at idle would probably cause you more problems at WOT and high rpms.

d

[GodziRRa]

I see. How do you do that putting a short tension on the # 1 cylinder between the plug and the coil pack? I have a used tension wire here, do I have to cut it and fit it in between? I wanted to use the loop since it's very simple to do and besides that is what Nissan recommends. Although it is quite hot in that area when engine warm, not easy to clip the loop without saying "aww". Doing this w/o gloves of course. hehe.

And another thing, how do you properly adjust ignition timing? While doing it, some say unplug the TPS, some say the AAC valve, some don't unplug anything at all.

Oh so 30 deg. advance will not have bad effects on cruise driving? And by the way mate, when your head gasket is 1.2mm thick or you have higher lift cams... will the optimum timing degree change? If so, will it be advanced or retard? I've heard about that before also.

[Dragon Humper]

If you didnt unplug anything then 30 deg sounds about right. Unfortunately my PowerFC sets to 20 deg with or without the IAC ( idle air control) plugged in so I can't say how much more timing the ECU will ad normally. 30 deg is what I would like to see though, makes for a happier engine at idle.

Pull the IAC plug and check the timing with the inductive pickup of the timing gun clamped around the feed wires to the #1 coil, you don't need to use the secondary side (at least my gun worked just fine off the coil harness). You should see 20 deg.(with the IAC plug off), if you plug the IAC back in and you now see 30, that's a good thing.



Jon.

[Skym]

Unplugging AACV is for when adjusting idle rpm (stops ECU playing with idle rpm). Unplugging one of the plugs on TPS stops ECU using idle tables (idle stabilisation tables can make the ignition timing fluctuate + or - 5 degrees) via it doesn't use idle contact inside TPS (there's WOT, idle contacts). The other plug on TPS should be the 0-5V plug.

The HT lead way with adjusting base ignition timing is shown in this manual on page 10 -

http://www.linkecu.com/support/documentation/g1-engine-management-documentation/gtslinkinstructionmanual

From what I understand, the reason why is ECU can adjust ignition timing up and down (idle stabilisation tables) + or - 5 degrees (depends on how it's been set by tuner) and timing light picks up on this via the wire going to coilpack number 1. Using the HT lead gives stable ignition timing on timing light, not - or + 5 degrees which makes it difficult to set accurately (also timing could be out due to old wiring). From what I understand, ECU idle stabilisation tables adjust's ignition timing to match o2 sensor making ECU adjust A/F ratio.

With solid 30 degrees, sounds like tuner has disabled o2 sensor due to engine having cams (running engine richer throughout powerband to match the extra air in engine that's provided by cams), raising idle rpm (how high depends on specs of cams) to make sure engine idles, which should result in higher base idle ignition timing.

GTS RB engine has 15 degrees (manual), 20 degree (auto) degrees BTDC (Before Top Dead Centre) for base ignition timing at around 650rpm when engine is warm. GTR RB engine idles at 950rpm, so base ignition timing should be higher to match. If engine has cams idle rpm is probably higher than 950rpm and ignition timing, fueling adjusted to suit.

Also from what I understand, adjusting camgears (adjustable camgears) out of factory specs requires adjusting CAS, ECU ignition timing to suit which would result in different settings.

Best to consult a tuner (local or overseas via email) before adjusting anything.

[NismoS-tune]

Be careful where you're picking up the signal. The loop at the back of the ignition harness is not a good spot to use. Better to either get a short plug wire and run it between #1 (front) coil and plug and put your pickup there OR put the pickup around the hot wire leading to #1 coil and push the pickup right up against the coil.

30 degrees advance at idle would probably cause you more problems at WOT and high rpms.

d

Like Dan says, forget the loop, it's too weak. I bought a short plug wire from Napa ($10) and clipped it there. 20 deg advanced is where you want to be stock ifI recall right. My car for what every reason was suggested to 12-15 advance but that came from people who say my 9.7-10.5 AFR at w0t is ok...

[GodziRRa]

Thanks for all the tips guys!

I've finally done it right... I guess. Well I just got an old tension wire and cut one side of it going to the coil pack num. 1 and get timing. And... voila! Timing using that method shows around 17-18 degree retard, I just loosed the CAS bolts and advanced it a bit to get it at 20 degree. I unplugged the AAC valve while doing this, and checked it again w/ AAC plugged in because have read the FSM and it did not state anything being unplugged while adjusting ignition timing. And weird thing also when I flip the inductive clip it still shows the same reading. But when I tried using the grey loop again, no matter what flipping I do it still read 30+ advance.

So maybe my Actron Timing Light doesn't work on the RB26?? I've heard that some modern timing lights isn't compatible w/ the RB26, it was said that "the timing light was picking up on the increasing current in the LOW tension lead at the very beginning of the dwell. And it would fire the light. So I was getting a light that was occurring SIGNIFICANTLY before the actual ignition event". Maybe it's smart for Nissan to sell those RB tension wire adapter for timing puposses only.

[GodziRRa]

By the way guys how do you read timing degree properly?? Reading it standing up front facing the cam front cover or you shoot and read it on a semi side position (on the right left lamp side aread)?

I just noticed the edge of triangle shaped point / guide of the marks is somewhat positioned on the side if you look at it closely. Because obviously these positions will give you a +/- 4 degree difference. So how to you read it gurus?

[Jasper]

Hi i need some help i have a datsun 260z wiyh a RB26dett engine stock
Running aftermaket ecu 0.8 bar boost
Timming is at 22degrees full boost and 10.9A/R in 4th gear full rpm
Does it sound fine?