Jump to content
SAU Community

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


Recommended Posts

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 :Dattachicon.gifImageUploadedBySAU 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.

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!

We seem to be going in circles here. :P

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

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.

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?

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 :unsure:

Edited by rondofj

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... ;)

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?

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

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?

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.

  • Like 2

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.

  • Like 1

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!

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

    • Hi, is the HKS  Tower Bar still available ? negotiable ? 🤔
    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
×
×
  • Create New...