Rb20 Spools As Though Brakes Are Held On

[ae86 boy]

Hey y'all. Lately my car, an r32 skyline has started behaving weird. When driving along at say 30kmph in 2nd gear, and the accelerator is applied ever so slightly, that car seems to bog down, the turbo starts spooling yet the car isn't picking up speed, probably even slowing a tad. It feels as though the brakes are being applied and the accelerator floored. ATM I'm thinking maybe faulty afm? Any thoughts...?

[Moodles2]

Slipping clutch perhaps

[ae86 boy]

Clutch is fine. Thanks for your input though. Even when in neutral and the accelerator applied ever so gently the revs don't rise and u can hear the turbo start to spool a small amount.

[34GeeTeeTee]

Are all the cooler pipes etc secure? Its not a boost leak hence the reason you can hear it spooling etc?

[ae86 boy]

Cooler pipes are sweet. Can also see it making boost on the guage.

[R31Nismoid]

Just because something is "working" does not mean there is not a problem.

Could be a leak on the cooler piping. A car will still make boost etc even with a slight leak.

[GTScotT]

ive actually had this happen to me intermittently, on my SR.

its happened when i free rev the motor, it will start to rev then the revs will stop and the turbo will start to work EXTRA hard like its spooling its ass off. id only be 'touching' the throttle from under the bonnet, and its making out like its in 4th gear up a hill...

Its only done it a few times so im honestly yet to work it out.... If anyone has input i also want to know? Im thinking its a restriction somewhere, like a blocked/collapsing exhaust OR something in my cooler. But the exhaust is pretty much a straight pipe, so i doubt that one.

LE WEIRD,

[Dose Pipe Sutututu]

perhaps use a timing gun and see if the timing is right, there's a chance it could be SO out of whack, the timing has been retarded so much there's crap all power, but there's loads of heat through the exhaust spooling the turbo.

never know right? easy to check anyways

[BOOZTJUNKEY]

Do this ^^^^^

if u can hook up a consult an run for errors that would help aswell

Does the car blow much greyish smoke on boost or under WOT

Try spraying butane gas or aero start around ur silicone hoses and vacuume lines while it's running .

if there is a leak the idle will pick up when u spray round the leak

[DVS JEZ]

Guys this happens on nissan ecu's when in cold enrichment. The car feels like its being pulled back by a trailer then it feels likethe trailer comes off and the car goes again. This normally dissapears when the car is at operating temp.

Does this sound like ur issue?

[GTScotT]

very close to it.

ill blame my tuner lol

OP can change his coolant temp sensor

[RDIRTY4]

Do you have an apexi pfc? If so, is there any chance you accidentally changed the afm settings? Just a thought... Happened to me before.

[R32Abuser]

Guys this happens on nissan ecu's when in cold enrichment. The car feels like its being pulled back by a trailer then it feels likethe trailer comes off and the car goes again. This normally dissapears when the car is at operating temp.

Does this sound like ur issue?

Jez,

To your knowledge, using a NISTune, can you disable and/or modify this feature? Its a complete pain in the arse on my car and makes the car drive like a bucket of shit when cold.

Attached is my log file.

This log file is with the car stationary and idling. You can see that as soon as I "blip" the throttle, the timing gets pulled from 40 degrees down to 10 degrees (at one point) and then shoots back up a moment later.

Have you found a way to fix this? Or as Pete has wondered, is it "hard wired" into the ECU?

Cheers,

David

ecutalk2142012.xls

Edited May 2, 2012 by R32Abuser

[R33 Eddy]

check timing lines up with Crank and Cams, your timing belt may have jumped a tooth or 2.

[Rolls]

I also had this problem and went to see Pete at nistune here in Adelaide when I had a road tune done, he was unaware of it being an issue but he looked at some of the cold coolant temp trim tables and set all the cells to 20 degrees in one of them, it completely removed cold start ignition trim doing this, means it drives like it is hot when you first start it, we did this just as a test to see if this was the correct map to edit, I will be getting him to put some sane values back in there next time I get it tuned so there is a cold start ignition trim, just not the pull all timing and build 2psi in neutral cold start it was before lol.

I will find the exact name of the map next tiem I talk to him, it was a 2D graph map with ignition vs temperature or something like that and it only went up to 2800rpm which is where it kicks out of cold start if you load it up.

My cold start was so bad I needed 50% throttle to drive the car in winter, and this was right on the threshold of kicking out of cold start so in winter when wet trying to pull onto a main road the car would pull all timing, spool up massively, then break into wheel spin, then stall up again making it quite dangerous to drive safely when trying to accelerate with moderate acceleration up to speed.

The only bonus of the old coldstart is my car would get up to running temperature in ~2km, now in 5km it doesn't even get off the gauge.

Edited May 4, 2012 by Rolls

[mico]

mine does his with djetro. slowly building revs at around 4k upwards. wot not a problem, but sucks when u come to a hill and all u can do to get up is go wot. it could be the switch from vaccuum to boost but i dont think so. unless my boost gauge is inaccurate.

[ae86 boy]

gtscott - thats the exact thing thats happening with my rb!!! and just like yours it isnt happening all the time - just sometimes, took it for a drive this morning and didnt have the problem?

as for timing - if this was the problem surly it would mean its happening all the time not just sometimes? hence why i think its electrical

dvs jez - sounds exactly like whats happening, computer is a nisstune, however the problem will be there even once the car is hot sometimes...

im going to clean the afm, check all the connections are good - my prusumption at this stage is a faulty wire thats sometimes shorting out/disconnected hence the random times it lags the way it does

[Rolls]

Just hook up ecu talk, it is obvious it is a tune issue as when it happens it fulls all timing back, it either happens or it doesn't.

the fact that changing the values in that table removed it 100% is pretty good evidence to me, the fact it doesn't always happen might indicate your temperature sensor is damaged.

Edited May 6, 2012 by Rolls

[jeffworld2]

I would suggest a new cold start valve.

Try logging aac and see what its doing. It might be 100% open just to get the idle up and then has nowhere to go from there.

FWIW mine has nothing under the plenum, now that its cold in the mornings it will idle at about 5-600rpm (GTR) and then 'warm up' to its usual 1050. During this time i have the same symptoms as you guys. If i had aac or air regulator i should see it idle more consistently and probably not pull timing to match what must be a weirdly low afm voltage for that afr

[Manuel Kasko]

Got the exact same thing with my 33 feels like shit to drive when cold

Frees up around 3500 rpm but below that you feel like your driving a truck up a hill

Makes it impossible to drive the car around the busy streets when its cold.

I have to baby it so bad I find myself getting overtaken by people walking haha.

Learnt to deal with it as Jez said it seems to be a problem with all RB Ecu's or Nistunes

Wouldn't mind finding the fix if the guys at nistune are able to help