1JZ boosts horribly when cold

[88mkIIIproject]

even on 50-60 degree days, before my 1j reaches close to NOT, or has run for 3-5 minutes, it sputters out horribly when the turbos start to spool. Under 2500-3,000 rpm, the engine runs completely normal, accelerates fine, and then sputters when it reaches + boost.

now when it is a really nice day (above 70?), or even on some random colder days it will boost completely normal, after running for a minute or two from a cold start. once it warms up, the engine runs perfect all day.

any ideas?

thanks

 

[AF1JZ]

Mine does it as well. A lot of cars kinda studder when they are dead cold. Even my IS300. It's never good to drive a car when it's cold.

 

[88mkIIIproject]

Mine does it as well. A lot of cars kinda studder when they are dead cold. Even my IS300. It's never good to drive a car when it's cold.

i try not to drive the car when its cold, but how long does an engine need to warm up before its not 'cold' anymore? it seems like 3-5 minutes is a lot to me (unless warm means once the thermostat has opened), or maybe i just need to buy a remote start and play it smart..

 

[AF1JZ]

I let my cars/bikes run for at least 5 mins for driving it.

 

[88mkIIIproject]

thats a good routine, i'll have to just remember to give myself more time...and also remember what an awesome engine I have, and its worth it to keep it happy lol.

are there any mkIII plug and play remote starters??

 

[OneJoeZee]

I don't have a problem with my car running strange when cold. I get in and drive. :dunno:

You should be able to get in and drive. Good idea to wait until its at NOT to do full throttle runs but it shouldn't act funny just boosting around a bit.

 

[AGlobalThreat]

You should NOT boost the engine when it is still cold.

You should also not let your car sit for a while at idle to warmup.

Read this: http://www.supramania.com/forums/showthread.php?t=48156&highlight=manual+drive

 

[OneJoeZee]

It was like 50 early. Really cold like the arctic circle. Shit's wack.

 

[OneJArpus]

eh 50 thats it, i love 50 lol thats not cold lol

 

[88mkIIIproject]

You should NOT boost the engine when it is still cold.

You should also not let your car sit for a while at idle to warmup.

Read this: http://www.supramania.com/forums/showthread.php?t=48156&highlight=manual+drive

thats a good thread, it does make sense...wouldn't have thought so at first.

here's a good link from it:

Yup, owners manual says, and I quote, "After the engine warms up for about 10 seconds, you are ready to drive. Do not race a cold engine. If the weather is below freezing, let it warm up for a few minutes before driving. Do not leave the vehicle while the engine is warming up."

So any ideas why my 1jz would be boosting bad, even after driving it for a few minutes? and when i say boosting bad, i mean right when it starts to boost, at half throttle, it sputters...

 

[OneJoeZee]

What's the condition of your plugs and your 02 sensor?

 

[Jostar]

You shouldn't boost in a cold motor, I have seen a few evo motors that did that & they ended up with crack pistons, They cracked cause of thermal shock, So i rather wait for my car to warm up & then go.

 

[88mkIIIproject]

What's the condition of your plugs and your 02 sensor?

new ngk's, not sure about 02...engine ran the same before and after plugs were changed.

it also cranks over for a few seconds before starting most of the time, forgot to mention that. it usually takes a good 2-3 seconds to start most of the time, other times it starts right up.

even when i have been driving it all day, it will still take longer to start up.

 

[Tim]

Yah, my car is the same way, even my last 3 mitsubishi eclipses were also the same way. I have to give my car at least 10 min of warm up so it doesn't break up in boost. My car even got a lot worst cold when I installed cams. I just give it a good 10min warm up, and I am cool:naughty:

 

[bloodasp90]

heres just my $.02, but even in the military, we have to let our trucks run for atleast 2-5mins before we go to full throttle to build up the air system, ive even been told by the guys here in japan (currently stationed) that in cold they said (10C) you should run your car for about 2-5 mins to let the materals in the block to expand, but after that, it can, but not likly to happen, but you could hert the head cause the lack of oil (only some engines) but i dont think that it would be the case for a 1jz..

 

[dugums]

I always just get in and drive. I keep the revs LOW (near the warmup range) in all gears until I am up to temperature.

I guess I don't understand how driving it at low revs is much different than standing still at those same low revs (for the motor) :dunno:

 

[Rich]

sounds like it's drowning on fuel > O2 sensor, intake air temp sensor, something like that could be fubar which makes the ecu enrich the mixture.

as for the other stuff; after a cold start, only wait for the oil pressure to rise, then engage the clutch and drive off and stay below 2500/3000rpm untill your oil is at NOT. Letting your car idle untill it warms up is wasting fuel/time.

Engine wear ONLY occurs when there's no oil pressure, as soon as you have pressure the wear stops as there is an oil film between axle and bearing caps. The reason you should not rev high or put a big load on the cold engine is because the oil film protection/lubrication works on flow, not on pressure as is widely misunderstood. Ever noticed your pressure drops when oil warms up? So if lubrication would be about pressure, then you should be able to put a big load on your engine when it's still cold because you then have high oil pressure...
So no, it's about oil flow. When oil is cold it is thick and doesn't flow enough to lubricate the bearings when under stress > high revs/big load, cavitation can then occur and then you WILL have metal to metal contact which destroys bearings.
That is the main reason not putting stress on a cold engine. However, cruizin below 3000rpm is not putting any more stress on the engine then when you let it idle. The oil warms up more quickly when driving and also, your gear box oil warms up, which is not the case when you let it sit and idle.
Furthermore the quicker your engine warms up, the quicker it will leave the cold start enrichment dumping fuel into your engine and dilluting your oil.

It also has nothing to do with clearances getting into spec when warming up, at least not in our engines, it does play a role in ultra high performance engines like F1 and funny car drag monster engines, but not on our engines which are designed for daily use. There is enough clearance on our engines to never be an issue, remember toyota (and all other car manufactorers) tests cars and engines from polar to desert conditions and they should start and go in all these conditions, that's what it's designed for.

So, many reasons to only let the oil getting to pump around and start driving asap.

and btw, I like driving in the cold, MORE POWAH!!

 

[bloodasp90]

and btw, I like driving in the cold, MORE POWAH!!

ohh how do i know that feeling in my skyline, opps did i just say that, DAMN JAPAN!! EVERYONE OWNS A SKYLINE, what a shitty car..

 

[Rich]

I just noticed I forgot to explain why I said "dumping fuel into your engine and dilluting your oil.

When the engine is idling, there is very little load on the piston rings, they're just rattling along up and down and the seal is at it's worst. This in combination with the cold start enrichment makes fuel and harsh gasses slip by the rings which end up in your crank case, where the oil reserve is.

Driving at low rpms puts enough load on the rings for them to seal which prevents dilluting your oil.

 

[88mkIIIproject]

I just noticed I forgot to explain why I said "dumping fuel into your engine and dilluting your oil.

When the engine is idling, there is very little load on the piston rings, they're just rattling along up and down and the seal is at it's worst. This in combination with the cold start enrichment makes fuel and harsh gasses slip by the rings which end up in your crank case, where the oil reserve is.

Driving at low rpms puts enough load on the rings for them to seal which prevents dilluting your oil.

thank you for the input, everything you explained made a lot of sense. i bet my oil is real polluted right now, i will have to change it asap.

Is the only way to check my O2 and other sensors by hooking up a data-logging tool that can see if these sensors are responding to engine variations?? Or is there a better way to determine whats wrong??

The slow starting seems to get a bit worse on cold starts, and it almost feels like it is missing when real cold...any ideas?

and yes, I love driving my warm 1j in the cold because of the extra power too :biglaugh:

thanks!