Timing about 30 degrees past the last mark?

[evolution23]

FIXED! - Issue was misfiring which was causing the shuffle. re-gapped to .8mm, taped some cracked coilpacks and its running better than ever now!



Alright i will try to make this as clear as possible... warning, a bit of reading ahead..so to start. I have been getting turbo shuffle in gears 3 - 5 under load while boosting for a few seconds. example.. traffics slowing, i dont want to gear down, guy infront of me changes lanes and theres no one for a mile now. I accelerate from 1800 (or so) rpm in 4th gear, ngines under load, turbos spool, then it feels like im hitting 100mph burts of wind every 1/2 second (or like the car is "chugging" and cant seem to get going). This only happens will under boost for a few seconds. i can boost great from 1 - 3 if im just getting up to speed from a stop. At first i thought boost leak.. then i thought coilpacks/spark.. neither made much sense. To me it seems like turbo shuffle from the wastegate opening and closing or something along those lines. Maybe someone can correct me if im wrong here?

Anyways, today i went to adjust my base timing and upon checking with the timing light it seems my base timing is approximately 20 - 30 degrees past the last timing mark (far right). i believe the last mark is 40 degrees, which would put me at 60 - 70 degrees right now. The car runs great (aside from the issue in the first paragraph) and idles/runs with proper a/f readings, CAS is centered and can be adjusted either way, timing belt was just put on about 1000kms ago and was set at TDC and all 3 marks were aligned with the belt markings. So what could cause the timing to be out this far? The only 2 possibilities i can think of are..

1. the timing belt is backwards, but this im sure would have destroyed my engine, and it would have never run? let alone as smoothly as it idles and runs now.

2. the motor is completely stock aside from 750cc injectors.. ECU has been chipped and tuned by the previous owner to compensate for the overkill. Timing may have been set like this in the ECU tune to compensate for 750cc injectors?

Any input is appreciated. It does not feel like a misfire at all, it feels like the car starts to "chug" along and cant get going, only while under load, at full boost (12psi), and after boosting for a few seconds. Thanks in advance!

[Dragon Humper]

Are you taking the reading from the "loop" at the back of the engine near the ignitor? If yes, stop that, bad monkey...lol. That spot is notorious for skewed readings for some reason, mine is out about 20 deg or so as well. Take the reading directly from the #1 coil harness up front, use the white wire.

Shuffle has many causes, do a shuffle search to find all the dirt on that. Dividing the "twin turbo" manifold that connects the two turbos together is supposed to help a lot.



Jon.

[evolution23]

Are you taking the reading from the "loop" at the back of the engine near the ignitor? If yes, stop that, bad monkey...lol. That spot is notorious for skewed readings for some reason, mine is out about 20 deg or so as well. Take the reading directly from the #1 coil harness up front, use the white wire.

Shuffle has many causes, do a shuffle search to find all the dirt on that. Dividing the "twin turbo" manifold that connects the two turbos together is supposed to help a lot.



Jon.

Yup i definitely was using the loop on the back! Would the shuffle be caused by the non-divided pipe? almost seems like the wastegate is opening and closing on me which i read could be caused by incorrect base timing.

[nimblestix]

Divided pipe makes a world of difference. If you can power through the shuffle until its gone then that's most likely the issue here, if not then I'd look at timing/tune.

Come by and we can test the timing with an actual plug wire on #1.

Timing belt was installed correctly and all timing marks were set to tdc.

Sent from a galaxy far, far, away.

[NismoS-tune]

The Y pipe is a minor culprit but not under load all the time unless you have too humor twin (like -10s). Soulss like a timing issue. I'm set to 15 deg now and no shuffle but I was initially at 15 ATDC (the ati degree stick is backwards lol) so I had shuffle all the time. You'll still get some shuffle until your modify your y pipe or get a real Y pipe.

The best and most accurate reading is with a spark plug wire on #1 coilpack. Then you'll know your true degree

I have an HKS racing chamber for sale. Used for 2 weeks. It replaces the stock Y pipe and is much better than a modified split Y pipe.

[RWD_GTR]

mine does this too.... sounds like a subaru. i thought injectors and coilpacks. post up what you find out.

[steveo1502]

I did this divided pipe mod a while ago, it helped a bit with the shuffle, but it diDnt totally get rid of it, I didn't cut the pipe though, I cut and bent a piece of aluminum to fit perfect inside the pipe, and epoxy in place with some metal epoxy or something . 2 yrs and still holding strong, some day I'll get a tig and do it right.. I've also had problems with my timing being way off, was on an rb20, car would run fine, but the mark wasnt even close, it was my cas, replaced it and all good, but dosnt make sense how the timing mark Was way off but it still ran fine

[evolution23]

Alright so the wire loop on the back of the engine was my problem with setting the timing but not with my issue. used cyl 1 and easily set the timing to 20deg. Took it for a spin and not only is it still shuddering/chugging/releasing, but its also misfiring badly now at 20deg so i centered the CAS again which is about 25deg of timing and it seems to run good (0 - 2 misfires id say in a pull now back at 25deg compared to an unknown amount of misfires because i cant count that many that fast at 20deg). So i dont think timing is my issue here. Something is releasing while under load and boost, to me it seems like a wastegate as it only releases for maybe 1/2 a second and does it continuously until i let off of gear down. Can definitely hear a whoosh whoosh whoosh every time it releases which is why i would say its seems like the car is "chugging" along trying to get going. and you can definitely feel it in the car every time it does it. it feels like im running over a cat or dog or hitting 15 small hedges in a row causing intermittent jerks of the car lol. idk how else to explain this. its damn annoying when trying to accelerate in 4th/5th gear on the highway.

[Skym]

The loop of black wire on coilpack loom goes to cylinder 1 and is where the ignition timing info from ECU goes through. Basically a timing light should pick up ECU adjusting ignition timing + or -5 degrees via idle stabilisation tables on ECU. If base ignition timing is way out, then the bearings in CAS have failed (common problem when CAS gets old) and needs to be replaced (as mentioned above).

Shuffle can be caused by the internal wastegate actuators not being at same psi on both turbo's causing inbalance of exhaust gas through turbine housings on both turbo's. Also can be caused by engine not being tuned properly (not all of the cylinders are producing same amount of exhaust gas), maybe problems with MAF's if don't have near to same voltage, leaking injector, bad injector loom, leaking intake manifold gaskets (causing a rough idle), lazy o2 sensor, just to name a few problems that could cause it.

If changed position of CAS and it improved, I would suspect camtiming is out (block or head could have been skimmed which would retard the timing).

When internal wastegate actuator fails (spring) you hear a rattling sound from wastegate hat moving around on back of turbo. Also when you pull the internal wastegate actuators off, put a vacuum hose on bulb part and T in a boost gauge. Then carefully apply compressed air to vacuum hose, you'll probably notice the internal wastegate arm behind bulb moves at a lower psi. The range should be 9.94psi-11.36psi for R32GTR internal wastegate actuators. The internal wastegate actuators should be at a similar psi to avoid shuffling. If have to, buy rebuildable internal wastegate actuators and use 2x good springs that are at same psi.

[evolution23]

Car is now boosting great, no shuffle at all, 0 misfires. It feels a little laggy and unresponsive at 3000rpm and 5psi but i think that might just be the timing needing a little tweak. However i am now boosting at 10psi instead of 12psi and im not sure why this has changed.

Anyways, the problem was indeed due to misfiring. in 4th/5th i guess i couldnt hear the car misfire but i did another compression test to see if everything was still good that way, cylinders ranged from 163 - 170psi so i regapped the plugs down to .8mm and ran 3 layers of electrical tape around 4 coilpacks with hairline cracks. Threw it all back together and it hasnt shuffled/chugged/whatever you want to call it yet!

[NismoS-tune]

I have 6 used but good coil packs for grabs if you want your sportscar to not have jimmy riggin tape around your coils lol

[evolution23]

I have 6 used but good coil packs for grabs if you want your sportscar to not have jimmy riggin tape around your coils lol

Ah i think it'll be fine. seems to run amazingly smooth now while driving/boosting so these will work for now! Thanks anyways!