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Discussion Starter · #1 ·
So i fired up my car the other week and noticed on cold, idle was way up at 1800 rpm

Also i had consult plugged in and reading AAC at 2%, is that 2% open or 2% closed?

Also when setting the TPS voltage to get the ecu to show a Throttle Closed condition i had to set the TPS voltage as low as 0.36V its usually 0.4 ish Volts

Its got me thinking is the throttle bodies fully closed? Do they need setting?
 

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See now I've been having the same issues. My idle sits at 2000rpm and no matter what I do it won't drop.
I've pulled the O2 sensors.. no change.
I've removed bumper and dowsed EVERY joint with carb cleaner.. no change so it's def not an air leak.
I've set the throttle body stops which was a pain in the arse but it's done.

I've checked timing it's good and stable.

I've checked voltage of tps and it's at .42v so pretty darn close to recommended .44v I think.

I run two vta bovs. The only thing I can think is that the return pipe that normally feeds back from the recirc valves to the other side is causing an issue but those holes are blanked off and they aren't leaking so I'm not convinced it's that.

I've now come to conclusion the stock gtr ecu is utter shite and needs binning which I need to do anyway as I wanna run a link. That way I can ditch the afms.. ignore the stupid crappy O2 sensors and not worry about stalling due to bovs.

Mine is and r32gtr too btw. Full engine build recently.

Hope you get some answers mate cos it's giving me the red ass personally.
 

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The only thing I've noticed that makes a small difference is the idle control valve screw. Unplug... fire up car.. adjust screw. Plug back in. I got the idle down to about 1500rpm but a quick bit of throttle and it went all over the place then stalled.

Oem ecu sucks goats balls. ****ing it off asap. Afms and nb O2 sensors and inability to deal with intake pressure drops due to a split second of bov being open shows how ****in outdated it is. MAP based tuning is the way forward.
 

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Have you tried taking the ICV off, give it a clean out and replace with a new gasket? Also check that the lines feeding it do not have any splits in them. I had a similar idling problem. Sometimes would just idle high and then other times hunt like crazy. I removed, cleaned and replaced the ICV with a new gasket and problem was solved.
 

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Previous owner of my 32 got keen and removed/cleaned the throttle bodies.
Ruined the seal to the spindles and removed the "dirty" throttle plate seals so she always idles high.
Vacuum leaks mean high idle.
What I also found was the PFc could not control the idle as well as the stock ecu, so she's back on the stocker until I find the energy to tackle that job.
I can live with a 1200-1500 idle.
 

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See now I call custard on that theory. The reason is I cleaned my throttle bodies as they were utterly filthy and gunked up and when they were snapped shut no carb cleaner leaked at all past the plates so I'd say they're quite airtight really.
I've cleaned the icv and fitted a new gasket and I have fitted a full silicon pipe kit underneath the plenum so all the hoses are new :)
I have heard vta bovs cause the oem ecu to idle high for no apparent reason. Makes no sense to me but are friend removed his blitz bovs because of the same prob and it's sorted now.
I'm gonna sort myself a link ecu out and go from there.
I'd be over the moon with a 1200 rpm idle :/
 

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Try increasing the tension on the spring for the BOVs. I have the Blitz ones and they are very easy to do. I had to adjust mine when I very first put them on about 10 years ago when the car had a standard ecu. I would guess the VTA ones should be as easy to adjust. If not enough tension on the spring, the plunger can easily be opened a touch when on vacuum idle, causing a leak and therefore problemos. It is worth a try amigo...unless you have already increased the tension on the plunger springs to maximum.
 

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INterested in this as I have a HKSFcon, TO4Z turbo and my car sits at around 1300 rpm. I dont see why any of these should sit that high. My R33 sat nicely at 900rpm for 7 years.
 

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Hehe thats what im getting aswell Ant, a link G4.....cant b arsed with this AFM crap
Don't think a Link G4 will magically fix your issues. It is only as good as the person you have trusted to do the work. Also nothing wrong with air flow meters problem is people are too lazy to fully calibrate them and take the easy route and go map and even then they do not bother with part throttle and optimising the map for road use.

I am a big fan of a properly mapped oem ecu and air flow meters. You do not see Nismo going for link or after market ecus on their Z tune.

Do you honestly think a UK tuner would be able to get a map better than Nissan or Nismo or even Mines?
 

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Discussion Starter · #12 ·
I doubt anyone knows the car better than Nismo and Nissan, no arguing there...

My point is that the old ECU is 80/90's transistor technology and by the time youve invested in either Nismo AFM's or Z32's and a power fc (again old ECU technology) you'd be better of upgrading to faster ECU's, larger memory, that can handle more inputs, offer closed loop control functions, boost control etc I think is a better long term investment

My idle issues have no bearing on choosing my ECU at all... I dont expect just a choice of ECU to sort out what is probably a Vacuum leak somewhere in my case...
 

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Don't worry about the TPS voltage.
The TSP idle switch should be on at idle.
Have you removed the AAV pipe from the bottom of the plenum to see if that shitty valve actually shuts? Remove the pipe, whop a bit of gaffer tape over the outlet under the plenum and pop the pipe back on. This effectivly blocked that pipe.
See what happens.
 

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I just block it off. If you start the engine and remove the pipe you can put your thumb over the end and see the revs rise and fall. This indicated that valves is seized. Without removing the intake system you cannot access it. It's a crap design.
 

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I doubt anyone knows the car better than Nismo and Nissan, no arguing there...

My point is that the old ECU is 80/90's transistor technology and by the time youve invested in either Nismo AFM's or Z32's and a power fc (again old ECU technology) you'd be better of upgrading to faster ECU's, larger memory, that can handle more inputs, offer closed loop control functions, boost control etc I think is a better long term investment

My idle issues have no bearing on choosing my ECU at all... I dont expect just a choice of ECU to sort out what is probably a Vacuum leak somewhere in my case...
Even so a 90s ecu mapped by Nissan Nismo will give you that perfect feel and drivability over a modern ecu mapped by a mediocre mapper fact.

But have a look at the usual stuff AAC, vacuum pipes Cas sensor, tps etc. also check for bad earth.
 

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As said.. nismo afms, new o2 sensors and wotnot end up costing near enough the price of just getting the link and doing away with it all. Also the link deals with boost control on board as opposed to standalone boost control unit.. I'd rather have the ecu do the lot really.
 

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Even so a 90s ecu mapped by Nissan Nismo will give you that perfect feel and drivability over a modern ecu mapped by a mediocre mapper fact.

But have a look at the usual stuff AAC, vacuum pipes Cas sensor, tps etc. also check for bad earth.
Any particular point on a 32 gtr for a bad earth ? I've checked all the bits mentioned and cleaned em. Cas sensor is great, tps voltage is all good and where it should be .44v
I had the bumper off and dowsed the fmic hard pipe kit with carb cleaner while on idle and it did nothing :/
 

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You may need to adjust the "flats" but that's not something I would do yourself maybe speak to RBmotorsport or RK about having it done.
Good luck trying to sort it.
 
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