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

[scotty nm35]

Or get a MAP based ECU and sell your Z32, sell your BOV

We seem to be going in circles here.

[scotty nm35]

My intake again - the black rubber breather hose on left from cam cover wraps under intake pipe before curling over it to the joiner/entry, courtesy of JEM's 3rd party fabricators ImageUploadedBySAU Community1407278665.866575.jpg

That entry is not pointing at the compressor wheel, half the returned air wants to go back up the intake, through the afm, which will be the cells you are seeing jump.

Simply blocking off the bov won't stop this happening, as the boost will escape back through the turbo compressor, essentially doing the same thing.

[XGTRX]

So is there a temporary fix so there is no recirculation so he can test it?

[scotty nm35]

No, if you disconnect the bov return and vent it, the car will run rich and do the same thing.

Put the stock intake on?

[XGTRX]

Damn.

[Ben C34]

He has already changed ecu once for no gain (really it went backwards) all for the sake of not modifying the bov return

A map based ecu will fix it for good though!

[Dose Pipe Sutututu]

We seem to be going in circles here.

hahhaah as much as I like AFM ECUs they're a pain in the arse

thus, I myself have gone to a MAP ECU..

you can however run atmospheric BOV on a PowerFC and lower the F/C RPM and lean out cells on rows 1~3 to stop it going all rich & shit.. I've done it before with my old R33 and was able to stop it from bogging down and shit

[rondofj]

Mount Z32 on cooler piping like Stao did once? Not a fan of high boost blowing at the delicate sensor.. :S And screw changing ecu again - no farrkin way haha.... $2000 for pretty much no gain just hopefully no bogging down on gearchanges.

[XGTRX]

Yep just dose it and enjoy

[scotty nm35]

You keep talking about major changes that will require retuning, when all you probably need is to angle the bov return a little towards the compressor.

Did the fabricator say he would stab you if you changed it? Why haven't you looked at it after the 100's of times it's been suggested?

[Dose Pipe Sutututu]

the Z32 will blow apart when it gets old.. suggest you don't

[rondofj]

I dont even know whos the fabricator lol.. And - this issue has only been happening with the recent switch to the powerfc this year.. The fact that the piping doesnt look convincingly bad has somewhat held me from doing it too..

And will this solve my intermittent rough running/ lack of power and 20-21L/100kms fuel economy? Don't think so

Edited August 6, 2014 by rondofj

[scotty nm35]

I have made many beautiful intakes, some of which were fail. It takes a fair imagination to design a perfect intake in your head and have it work first time off the bat. Bov returns are the hardest to get right, and they change with some bov's and setups, also depending on the boost you run.

I would be asking for the fabricator's details, as it's in his best interests to get it right and learn from his mistakes. Otherwise I can send you one of my intakes to try out...

[AngryRB]

If some one connect the vacumn line incorrectly on the pump, then you will get 20L/100kms cause instead of allowing only vapour from the tank to the manifold, raw fuel gets sucked thru

under vacumn conditions.

Who did the pump?

[rondofj]

If you were in Sydney then you do my pipe! haha..well I can't try out your pipe, no guarantees it would fit - its one of those 'on-site' jobs aye

[rondofj]

If some one connect the vacumn line incorrectly on the pump, then you will get 20L/100kms cause instead of allowing only vapour from the tank to the manifold, raw fuel gets sucked thru

under vacumn conditions.

Who did the pump?

I did -3 years ago, and yeah economy has always been crap since a long long time, with the Nistune as well, dont know exactly since when. Good point - I didnt even know about the vacuum line just the fuel return and supply line - worth having a look.. What is this vacuum line and does it run from intake manifold?

[XGTRX]

Didn't someone reposition their afm somewhere near the intercooler to solve a similar issue? Can't remember exactly.

[Dose Pipe Sutututu]

If you were in Sydney then you do my pipe! haha..well I can't try out your pipe, no guarantees it would fit - its one of those 'on-site' jobs aye

I bought one and it bolted up to my stock airbox going to a 4" snout of a Hypergear SS2.

However, I liked pigeons and tuuurrkeeys more so I installed a pod filter to attract slarts & cops.

[AngryRB]

I did -3 years ago, and yeah economy has always been crap since a long long time, with the Nistune as well, dont know exactly since when. Good point - I didnt even know about the vacuum line just the fuel return and supply line - worth having a look.. What is this vacuum line and does it run from intake manifold?

Its easy to mix them up, I found this on my falcon, it runs from the fuel tank to the charcoal canister then under vacumn a valve allows the vapour into the manifold to be burnt. Not exactly

sure on the skyline but it would be same or similar. The vacumn line outlet on the pump is designed to not let fuel though, mine wasn't on that outlet, resulted in 20L/100km and the manifold

was soaking with raw fuel, on deceleration the motor choked and lost power til the fuel was cleared out of the manifold.

[GTSBoy]

OK,

So I return to this after quite a few posts, but based on most recent feedback from Ron and various of the replies since I see the following as being the most likely scenario.

1) Sudden pulse of AFM signal upward with consequent increase in ECU load signal up 5 or 6 cells definitely implies it's a reversion problem. Blocked BOV will of course cause that - and you have seen it occur with blocked BOV. Wrong BOV return design will also cause it, and you have seen it with the BOV connected. Therefore....

2) BOV return is not right. The connection from the cam cover hose doesn't matter - only the angle of the BOV return does. I suggest further speculation on the cause of the hesitation problem should be put on hold until someone remakes the BOV return.

3) High fuel consumption. As I see it your coolant temperature is 10 degrees too cold and that could easily cause the ECU to add a bunch of enrichment - especially if it was at the correct temperature while it was being tuned. This should be the work of 5 minutes for Yavuz to look into and report on what the ECU is doing. And to fix it might take only as much as another 5 minutes if it needs fixing in the tune or maybe 30 minutes if you need the thermostat changed.

4) High fuel consumption. The tank breather situation is a bit special on Neos anyway. The stock ECU has a whole bunch of maps (only recently uncovered and correctly identified by Matt at Nistune) around the emissions purge control logic. There is a solenoid valve that is only allowed to open under certain conditions to allow the vapours to be purged. If the PFC doesn't do this properly and/or there has been a physical f**k up of the system with various works (like FFP installations) then perhaps there is an avenue here for fuel consumption to go high. But I would imagine that if the ECU was properly running closed loop and most miles were done under cruisey closed loop conditions then it shouldn't be as bad as Ron reports.

5) High fuel consumption. A f**ked O2 sensor will do this to you. Replace it or plan to live without it. Choose one.

As to Yavuz's statement of the load jump causing R&R - well, it's not R&R because there's no such thing in a PFC unless it is deliberately tuned that way (ie the tuner makes the top end of the maps as mentally retarded as Nissan did!). But I suppose functionally it is equivalent to R&R if those load cells add a lot of fuel and have less timing. Terminology doesn't really matter - I think we can be sure that it's a reversion problem and that you need to fix the reversion!