Car Performs Better After 2-3 Min Idle Warmup

[Brezza]

my car is a little sluggish until it comes up to temp then it is great.

i usually if i really have to drive it cold i just keep it in one lower gear and drive at slightly higer rpm with little load as possible.

so for example 3rd gear at 50 or 60km/hr

the temp does goe up a little faster and because there is less load on the motor it doesnt have to work so hard.

on my GTR its all due to the Nistune ECU being in cold start mode.

[stolen-gtr]

thanks for all the replies...

i understand that the engine will obviously not be the same when its cold (mafia explained this well)

ill try lay this out a bit better as it may have been mis interpreted slightly...

scenario 1:

start car, let idle for 2-4 mins - driven extremely gentle - no load etc (like paul said). driven for 15-20 mins until full operating temp, engine feels perfectly normal and responsive like it should.

scenario 2:

start car, drive within 30 secs of starting - still driven being extremely gentle, minimal load etc (like paul said) . drive for 15-20 mins like this until full operating temp is reached, engine still feels sluggish like it did when it was first started.

my understanding was that once it has reached full operating temp, it should be the same always no matter if it was driven straight away being babied around, or let idle for a few minutes.

basically i would just like to know what the difference is between these 2 scenarios after the engine has reached full operating temp...

thanks for the help i dont want to start any wars here lol, sorry if i have repeated myself

[89CAL]

if you have stock ecu try ressetting it? sorry if youve said its aftermarket and ive missed it but if its stock ecu just try to reset it.

Its simple enough to do and theres alot of silly little things the ecu learns or whatever it does that are fixed with a simple ecu reset.

might not fix it at all but its worth a try for the 5 mins it takes to do

[stolen-gtr]

if you have stock ecu try ressetting it? sorry if youve said its aftermarket and ive missed it but if its stock ecu just try to reset it.

Its simple enough to do and theres alot of silly little things the ecu learns or whatever it does that are fixed with a simple ecu reset.

might not fix it at all but its worth a try for the 5 mins it takes to do

sorry yep i should have mentioned its a rb20 nistune ecu..not sure if that changes anything?

[89CAL]

it could... I dont really know anything about nistune, I wouldnt think it would have anything to do with the loss of VCT but yeh not sure have to find someone who knows a bit about nistune, maybe theres something in the tuning that will fix it?

[Marcus89]

as the others have said, just drive it normally (dont load it up, dont bring it on boost) until the engine is warm

wamr is considered around 50deg water temp - or when the water temp guage on the dash starts to move

Or not water temp gets up in about 2-3 mins in my car but oil temperature isn't up to 70 degrees (lowest value on my stock oil temp gauge r34) until closer to 10 minutes of driving

[Marcus89]

sorry yep i should have mentioned its a rb20 nistune ecu..not sure if that changes anything?

Nistune utilises the factory cold start function so if it is something strange the ECU has learned over time reset may be good although i have no idea what the go is with resetting it when you have Nistune already installed and what not should be the same but don't take my word for it

[GTScotT]

sorry yep i should have mentioned its a rb20 nistune ecu..not sure if that changes anything?

it could play a part but its highly doubtful, as the current tune is more than likely built off a stock map with stock cold start config

[Dose Pipe Sutututu]

I have proper reasoning

If you're running a powerFC the person who tuned it probably hasn't adjusted the Water temp vs Fuel Correction table so when the car is cold, it's running lean as fk and hence feels nice and punchy, by the time the car has warmed it is running at optimal fuel mixture.

When I first got my car and installed a WB I noticed that when the water temp was at 10, 30, 50 degrees the A/F was like at 14.5 nearly stoich which should only be at operating temps.

now it's rich as fk when its cold

water temp @ 10 degrees = 13.0 A/F

water temp @ 30 degrees = 13.5 A/F

water temp @ 50 degrees = 14.0 A/F

water temp @ 80 degrees = 14.7 A/F

[paulr33]

on my gtst after 3.5 minutes of operating the water temp is 45deg, oil pressure is good and reacts to engine load

at this point its ok to drive the car normally and load it up a bit. i certainly wouldnt smash every gear to redline but its perfectly normal to load it up and bring on some boost if you want afer this warm up time. my gtst is 13 years old, 225,000 kms on the clock so i dont see any point running for 10 minutes in baby mode then loading it up

[DuFFR32]

I have EXACT same issues with cold start. My ecu is nistune rb20det, so im guessing its a kinda choke mode its going into. Sometimes when i start the car its fine and then 10m or so down the road it goes into this mode and if definately makes you put the throttle on more to get the car moving, its actually harder to drive because you dont want to go into positive pressure (boost) but still have to get the car moving while looking at the boost guage trying not to let it get above 0psi

My care feels like a slug when in this mode and turns off when temp gets halfway and runs normal again,

My bet is its something to do with a Nistune setting. Id love to find out how to fix this problem!

can a nistune ecu be reset?

[zoomzoom]

Probably late notice in the thread but boosting on a cold engine and warming an engine by idling for many minutes is bad bad bad bad bad.

However I have noticed the car ran much better on cold after cleaning the AAC.

[KiwiRS4T]

I always warm up cars by driving them (like the OP without hammering it from the off). Other possible problems faulty temp sensor or too heavy grade oil?

[Chibs]

my car is the same... 2-3 minutes of absolute RUBBISH... very rough

Then it drives smooth... and another 10 minutes .... im boostin ! =)

[stolen-gtr]

wow im glad someone has actually experienced the same thing as me!

im not sure if its a coincidence but i went away for a while and disconnected the battery, and when i came back, first start it was really responsive. But now after driving it regularly it seems to be intermittent.

i would guess the way to reset it would be like normal rb20 ecus and disconnect the battery, and drain the backup power from it (sorry if that terminology isnt correct)

so sounds like it could be related to that....but just a guess

I have EXACT same issues with cold start. My ecu is nistune rb20det, so im guessing its a kinda choke mode its going into. Sometimes when i start the car its fine and then 10m or so down the road it goes into this mode and if definately makes you put the throttle on more to get the car moving, its actually harder to drive because you dont want to go into positive pressure (boost) but still have to get the car moving while looking at the boost guage trying not to let it get above 0psi

My care feels like a slug when in this mode and turns off when temp gets halfway and runs normal again,

My bet is its something to do with a Nistune setting. Id love to find out how to fix this problem!

can a nistune ecu be reset?

[mattymagoo22]

People idling your car is in no-way the best way to get your car up to temp, do you really think it takes 30seconds to 10 minutes to get oil pressure, NO! You have oil pressure the second that the oil light goes off on the dash (this light only comes on when the oil pressure is less than 20kpa) it may not be the same as what it reads when warm but you've got pressure.

The only reason you used to warm your car up is so that the fuel coming out of the CARBY could be vaporised and allow the car to be drivable, with out doing this the car would mis-fire, cough, fart and splutter and be close to un-drivable. Manufacturers suggest that you are actually wasting fuel when idling to warm up and suggest you drive it, as with fuel injection the fuel is vaporised the minute its sprayed through the injector, hence the car is more drivable when stone cold. Frictionless coatings, closer machine tolerances and improvements in engine oils all aid in protecting your engine through warm up.

It's been a while since I got to hear from an engineer about the way they tune the ECU for cold start and they were doing crazy things like running super rich like 10.7-11 (i think, maybe richer it been a long time) then bringing them out lean to warm the cat and also making the Automatic hold gears so the engine would rev harder to help get coolant temp up all while the engine was under a given temp. They are using the electrical equivalent of the old air pump used on a 202 holden motor to get past emissions during the really rich part of initial start up.

The longer it takes for you engine to reach operating temp the more it wears. In an ideal world your car would never cool down and the engine life would be drastically increased, however, this isn't practical for everyone who isn't a taxi driver.

I'm not saying start you car and have it bouncing off the limiter but don't putt around not allowing your engine to rev, I agree with paulr33 as soon as the temp gauge begins to move its warm enough.

Cheers.

[stolen-gtr]

what youre saying is fair enough and makes sense, but the point of the question was to find out why it seems different after those few more minutes of letting it sit. you obviously know youre stuff so theres nothing to argue about, and totally makes sense about driving warming it up quicker. now that ive actually seen it make a difference after the battery had been disconnected, im going to assume its something going on with the ecu and cold start...so i guess the best thing would be to do is talk to someone who has an understanding of the tune and cold start settings...thanks for your response anyway its always good to learn a thing or two

People idling your car is in no-way the best way to get your car up to temp, do you really think it takes 30seconds to 10 minutes to get oil pressure, NO! You have oil pressure the second that the oil light goes off on the dash (this light only comes on when the oil pressure is less than 20kpa) it may not be the same as what it reads when warm but you've got pressure.

The only reason you used to warm your car up is so that the fuel coming out of the CARBY could be vaporised and allow the car to be drivable, with out doing this the car would mis-fire, cough, fart and splutter and be close to un-drivable. Manufacturers suggest that you are actually wasting fuel when idling to warm up and suggest you drive it, as with fuel injection the fuel is vaporised the minute its sprayed through the injector, hence the car is more drivable when stone cold. Frictionless coatings, closer machine tolerances and improvements in engine oils all aid in protecting your engine through warm up.

It's been a while since I got to hear from an engineer about the way they tune the ECU for cold start and they were doing crazy things like running super rich like 10.7-11 (i think, maybe richer it been a long time) then bringing them out lean to warm the cat and also making the Automatic hold gears so the engine would rev harder to help get coolant temp up all while the engine was under a given temp. They are using the electrical equivalent of the old air pump used on a 202 holden motor to get past emissions during the really rich part of initial start up.

The longer it takes for you engine to reach operating temp the more it wears. In an ideal world your car would never cool down and the engine life would be drastically increased, however, this isn't practical for everyone who isn't a taxi driver.

I'm not saying start you car and have it bouncing off the limiter but don't putt around not allowing your engine to rev, I agree with paulr33 as soon as the temp gauge begins to move its warm enough.

Cheers.

[DVS JEZ]

its a mental thing i reckon,

put the car on a dyno and see if the tractive effort is different on cold engine with/without a warm up idle, i reckon it will be the same

[KiwiRS4T]

As a matter of interest what type and viscosity oil are you using?

[mattymagoo22]

what youre saying is fair enough and makes sense, but the point of the question was to find out why it seems different after those few more minutes of letting it sit. you obviously know youre stuff so theres nothing to argue about, and totally makes sense about driving warming it up quicker. now that ive actually seen it make a difference after the battery had been disconnected, im going to assume its something going on with the ecu and cold start...so i guess the best thing would be to do is talk to someone who has an understanding of the tune and cold start settings...thanks for your response anyway its always good to learn a thing or two

Yeah for sure, it would be interesting to see what causes this as I'm pretty sure that those ECU's don't learn. You don't seem to be the only one experiencing the symptom though. What are the theory's behind disconnecting the battery and the effects its meant to have?

I tend to agree that it may be placebo effect, but can't really say without experiencing what you're saying.

Cheers Matt.