Hey Guys-
I've had an issue since day 1 with my GSR that I'd like to resolve if possible. When I transition from boost to vacuum without completely releasing the throttle, my car jerks or "bucks" HARD... so bad that I can feel the shock through the drivetrain. I've owned the car for 2 years now and I'm starting to get some noise and a "loose" sensation in the drivetrain that definitely has me concerned.
I owned an X MR previously and never it never had any hint of this issue. I'm 100% certain it's not the tune because again, the car has had this issue since it was fresh off the showroom floor.
Is there a fix for this via tuning? I did mention this to the guys at Road Race Engineering (tuned both of my cars) at one point in time but they had no clue what I was talking about.
Thanks!

 

Manual or auto?

Stock BOV or aftermarket? If aftermarket, is it a recirculating BOV?

Any other mods?

How many miles when you bought it?

 

Manual (GSR). Synapse DV recirculated with bolt-ons and a tune... again, I've owned the car since it had 000004 miles it has done this since day one through every stage of modification. A buddy of mine has a 2014 GSR and his car does the same thing.
I'm hoping it's an error in the factory ROM and someone has figured out how to correct the issue.

 

Mine used to do that only on 5th gear and WOT. I have a 08 x GSR, the dealer had a TSB for this and flashed my ECU and took care of that problem. You said your car is tuned, so it should have taken care of that problem. What I would do is to clean the MAF, check spark plug to make sure the gap is not closed, you don't know how many times I've seen that. Also take off the aftermarket BOv and try the EOM one.

 

^Sounds like that may be a different issue. At WOT I have no issues.... only when I transition from boost to vacuum and it happens in any gear.

 

This usually happens to me when I release the throttle slow in high gear. If I let it go fast so that the BOV purges all pressure it's fine.

 

Use the yellow spring in the Synapse and reduce your Tip-out Fuel Enleanment values to 0.

 

I "fixed" this issue a long time ago with my Synapse unit. I had to cut the yellow spring down a bit. It's been so long I don't remember how much of it was cut.

 

+1

mines the same way especially if im driving up a hill. if im on or off the gas its fine its just when im barley on gas and its right at the trasition of boost and vacume

 

Is this for every cell? As in, set all values to 0?

 

since this is also usually a 5th gear issue thing one thing i've noticed is if im just crusing at a constant speed which is when this would normaly happen if I turn on the cruise control it wont do it.. just a fyi

 

if you put in tighter motor mounts that might help, but really, any manual car will do that

 

What's more annoying is the bucking in first gear when creeping along.

 

the loose sound could probably be a u-joint if it sounds like a two hammers lightly smacking each other.


also, the 'bucking' you feel... does it happen when say...you're in like 3rd running maybe 4k rpms and you gas it a little, then let off...then you press the gas and the car jerks for a second?

happens to me too, no clue why, guessing its something with the boost or w/e.

 

Yes! My car will buck under those conditions. Sometimes more... sometimes less. And in just about any gear. I also get the bucking in first gear while creeping, but the load (and boost) conditions are different there so I'm not sure if it's the same issue.


Cravnpup.. have you adjusted the tip-out fuel enleanment values on your ROM? I got a PM from another member suggesting that, plus some info from another site where a member saw some improvement by making the same adjustment so I'm thinking about giving that a try. I'd like to hear from someone that has done it to their car first though!