Jump to content
SAU Community

Power Loss On Downshifts, Bouncing Idle And Slight Hesitation At Specific Rev Point -R34Gtt


Recommended Posts

To properly check tdc you need a dead stop in the plug hole, or a dial indicator with a long plunger. Looking at it isn't good enough.

Does the PFC display what timing it is running? You should look at it , and if says 20 set cas to read 20 etc...

It always says 15 on the commander (after warming up n idling), even when I set it to 20 yesterday (with TPS off), TPS connected it reads 15 at crank AND power fc as well.

Omg did you not read anything?

Irrespective to what is set on the CAS the ECU won't show what's set. It will always think it's 15 even though the CAS has been dialled to 30

To properly check tdc you need a dead stop in the plug hole, or a dial indicator with a long plunger. Looking at it isn't good enough.

Does the PFC display what timing it is running? You should look at it , and if says 20 set cas to read 20 etc...

^^ I do not know what is this. Dead stop/ dial indicator. haha

At some point you need to make a call and take it somewhere to get it sorted.

If all of this is going over your head just save the hassle and pay someone.

If you don't know what a dial indicator or dead stop (also called piston stop) is, Google it! Google how to check tdc. It's not hard.

Edited by Ben C34

Why pay someone with no guarantee of a proper fix?? When its more rewarding and easy to ask, learn, try etc. And spend money buying my own tools/equipment rather than pay a workshop's labour. I would only go to a workshop after I have exhausted all avenues, tried everything and got as desparate as a cheap crack whore..

And I have already mentioned many times that the bov entry/power loss on shifts is a problem that doesn't really bother me anymore - I can live with it. Lets take this out of the equation, it will be my last fix.

Lets fix the timing first! hehe.. at least I discovered it was the timing that was causing power loss after all.

Edited by rondofj

Well so long as you are having fun with what you are doing that's all that matters.

Keep in mind by cranking in heaps of extra timing your risking popping your engine , which would cost more than getting someone to fix your current problem. I'm sure your tuner would freak out if you told him you added 6 degrees to the map and messed with the cas.

And by the way, didn't you cause the power loss by messing with the cas?

Edited by Ben C34

That last sentence makes me actually worried, just reading it on page 17 of this thread..

One does not simply add 6 degrees to the map and mess with the CAS :P

  • Like 1

My guess would be Yavus set timing at 20deg with TPS connected and you have played with it at some point then reset it to what it should be, try setting it to 20deg with TPS connected and see how that goes

And I wouldn't be surprised if that puts the bolt on the CAS back in the middle

Because then you might muck around with something else, make it a bit lean and BANG... For this critical stuff you are paying a workshop for labour that includes knowledge, wisdom, and a system of doing things properly. One of your mistakes might cost you your engine, a good workshop won't make that mistake.

  • Like 1

Well so long as you are having fun with what you are doing that's all that matters.

Keep in mind by cranking in heaps of extra timing your risking popping your engine , which would cost more than getting someone to fix your current problem. I'm sure your tuner would freak out if you told him you added 6 degrees to the map and messed with the cas.

And by the way, didn't you cause the power loss by messing with the cas?

This is a strange one, I thought that as well, but it wasn't immediately too obvious on that day, maybe 2-3 days later, could have been my mind playing games.. I do think its the messing with cas, I keep saying before it was on the centre of the three bolts when i last set timing, and before I took it off to put Wolverines one in, now its almost fully clockwise at the same timing.

Could it be because I messed with the TPS before that and then brought it back to 0.41V @idle which is what it originally was. And thats all I messed with. And lost that white TPS plug cap.

Cranking extra timing on the pfc brought my power back to what it was before, maybe a bit sharper now, and it doesn't ping/knock at this level, does it mean its still unsafe? Dont understand this one. But crank up 1 more degree and it will knock at high rpm in 3rd.

Edited by rondofj

My guess would be Yavus set timing at 20deg with TPS connected and you have played with it at some point then reset it to what it should be, try setting it to 20deg with TPS connected and see how that goes

And I wouldn't be surprised if that puts the bolt on the CAS back in the middle

^^ THIS seems like the most likely thing that has happened. Will be trying that. What do the others think?

Stock ECU has ignition ramp to stabilise idle, thus when TPS is at 0.45v aka throttle off.. closed loop idle/o2 is enabled - this is why on a stock ECU when you're trying to set your base timing you'll notice it jumps all over the shop.

PowerFC I believe does not have ignition ramp to stabilise idle, so there's no need to unplug the TPS to set base idle and/or the base timing.

based on my logging I've found the idle control does.... I don't have 15 degrees set anywhere on my map yet log monitor shows 15 at idle.

I still dont get how cranking up the maps 6+ degrees can be detrimental to my motor as it doesnt knock at that level and goes hard like before?

Because you don't KNOW that it's not knocking. You are trusting very unreliable knock sensors to tell you that it's not knocking. It could well have more knock than is healthy and you can't hear it.

You have arbitrarily advanced the ignition 6 degrees everywhere and you DO NOT know for sure that it was actually retarded by that amount. It may well have NOT been retarded and in fact has some other problem causing your poor performance. The combination of the possible other problem + 6 degrees extra timing might not be real healthy.

Just because it now goes hard again doesn't mean that all is well with the world. It might, but it is not bulletproof by any means. And unless you can do a few of the basic verification checks that have been outlined you are flying very blind.

Edited by GTSBoy
  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
×
×
  • Create New...