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

[rondofj]

Overrun/overrev on downshift.

Also, and by the way, when you say "wedge" do you mean the ridge of high timing running along the top, or do you mean the little dip right at the end closest to the viewer?

that little dip in orange and yellow closest to viewer - just two values of 30 affect this.

[GTSBoy]

See, I think everyone else thought you were talking about the ridge.

[rondofj]

Nope, had a play in Excel, those two values of 30 are a big jump from the adjacent LHS values of 40 & 43, making them say 38, 39 smooths it out, the tuner was probably eating his pizza and forgot that - but then again I doubt these two odd cells will do 'anything' to how it drives.

Saying that - what do you guys think of that purple 'hole' in my fuel map (mid rpms, low/mid load), is it dodgy or kinda ok? These are values from 84-94 on this area of the table

Edited August 20, 2014 by rondofj

[GTSBoy]

Lean cruise.

[Dose Pipe Sutututu]

Fuel map looks fine. RB25 motors like less fuel around 50kPA when compared to near absolute or 0 kPA

Also around that area timing starts to decay when compared to higher vacuum areas.

It's normal man, you can't just look at the fuel map and go "oh mah gord deres a fuel hole"

Simply put it the motor isn't needing fuel around there to hit stoich.

[rondofj]

Cool man I take up your offer of swapping afms in the weekend, but I think I will need it for at least a coupla hours to test in diff loads/conditions if thats ok? And also if u can come for a quick drive to monitor things who knows u find something I didnt. And James Squire will be there too so dont worry.

[iruvyouskyrine]

Datalogit kit is money wasted just to diagnose a problem/quote]

You won't do this but you will buy a new ECU? And the old ECU had data logging? And you don't like how the car drives and this issue has been happening for moths and you have spent countless hours trying to solve the issue?

Ok.

[rondofj]

Oops. Where did I say I will buy a new ECU?

[iruvyouskyrine]

You went from NISTune to a Power FC.

[rondofj]

Yep bought not 'will buy' as you said, will never buy a new ecu again unless different stock car haha

[iruvyouskyrine]

Whatever. You still already bought it to try and fix this issue. Good luck.

[Ben C34]

So eventually when you manage to log what's happening, and see that the ecu Is jumping cells, due to the afm being affected by the bov return, what are you going to do then? The afm can't be faulty only when lifting off the throttle.

The only two options here are shit tune or an issue with the bov return. The tuner is well respected, and it's pretty hard to do a shit tune on a power fc after I'm sure he has done 100s. So that leaves the bov return.

[XGTRX]

So eventually when you manage to log what's happening, and see that the ecu Is jumping cells, due to the afm being affected by the bov return, what are you going to do then? The afm can't be faulty only when lifting off the throttle.

The only two options here are shit tune or an issue with the bov return. The tuner is well respected, and it's pretty hard to do a shit tune on a power fc after I'm sure he has done 100s. So that leaves the bov return.

I am sure you mentioned this on page 2 of this thread....

[rondofj]

well as I've said a few times already - I'm not too concerned with the power loss on shifts right now (its a MINOR issue and is most likely the bov return as others have said). What I am concerned about is where has my power gone the last 3-4 weeks without changing anything and the rich running (fouled plugs, fuel smell, fouled O2 sensor)/ fuel economy is my main problem that I'm trying to fix. We will see about the economy on my next fill-up as I changed the O2 sensor - but expect bugger all difference.

Which leaves AFM as suggested by some.

And tune? Well you've all seen my tune now haven't you, are you able to tell if its shit or not cos I have no idea

[rondofj]

So eventually when you manage to log what's happening, and see that the ecu Is jumping cells, due to the afm being affected by the bov return, what are you going to do then? The afm can't be faulty only when lifting off the throttle.

The only two options here are shit tune or an issue with the bov return. The tuner is well respected, and it's pretty hard to do a shit tune on a power fc after I'm sure he has done 100s. So that leaves the bov return.

well as I've said a few times already - I'm not too concerned with the power loss on shifts right now (its a MINOR issue and is most likely the bov return as others have said). What I am concerned about is where has my power gone the last 3-4 weeks without changing anything and the rich running (fouled plugs, fuel smell, fouled O2 sensor)/ fuel economy is my main problem that I'm trying to fix. We will see about the economy on my next fill-up as I changed the O2 sensor - but expect bugger all difference.

Which leaves AFM as suggested by some.

And tune? Well you've all seen my tune now haven't you, are you able to tell if its shit or not cos I have no idea

[Dose Pipe Sutututu]

Your tune, timing figures look safe, fueling is hard to tell without a wideband... you need logs.

[XGTRX]

So you want to fix the problem without doing what you really need to do.. that is log data... Interesting

[XKLABA]

Reversion will cause the symptoms your are describing

Its hard to look at a tune map and know anything about it without seeing its effect on the motor

Your timing isn't to far out there, maybe a bit advanced at high rpm low load but nothing that is going to cause the issues you are describing

Disconnect your BOV from inlet pipe and vent to atmo and see if power lose is still there, that will either confirm or rule out reversion

[rondofj]

Yep will do that cheers. Meanwhile figured out how to do a map trace. Still a noob u see .

See pics -1st one is a 10-12min cruise to shops, parra to granville in syd, traffic lights, stops max 50/60km/h NO boost.

2nd one is same drive back with three 2nd/3rd gear pulls at 21psi max. So does it look like its accessing the right cells or has it gone a bit gay?

Edited August 23, 2014 by rondofj

[Dose Pipe Sutututu]

Looks fine, however with logs with a wideband connected to it will easily show you what's going on.

It's hard to say what it is and not doing because the load axis is an interpretation of TPS and AFM voltage