Engine Holding Back When Cold

[agentx]

Hi guys, my r32 gtst has an issue where it just doesn't feel like revving / driving smoothly till a certain RPM. this ONLY happens till the engine is cold and the problem is gone EXACTLY after the temperature reaches the normal half way mark. Till it reaches there, the car doesn't pull right until I rev it over 2500ish RPM - after that it drives better (but I think it uses too much fuel as I can see black smoke on high revs). On Low RPMs, it feels like something's pulling the car back.

I spent 400 bucks on brand new coil packs as someone suggested that could be the cause but turns out it wasnt ... can someone please guide me to what I can replace next to try and find a solution?

Its got a dr drift ECU with a bigger turbo but stock fuel pump and mostly everything else is stock.

Thanks for your time guys!

[krzysiu]

My r33 only did that on the stock ecu. Ran like ass till it was warm. Powerfc and coilpacks it never did it again

[MBS206]

O2 sensor would be a starting point, and water temp sensor too.

[SargeRX8]

Isn't the car still in warm up mode? I wouldn't say sensors because, well, you said after its warm it works fine. f**ked sensors wont work, especially when warm, it will just shit everything. What kind of oil are you using?

I tend to find when its really cold my car is ugly to drive, I just let it warm for about 5 minutes before I drive it.

[boiracer]

do the o2 sensor anyways if you havent. pull the AF meter out and clean it.

by the sounds of it you need to get it tuned if you have black smoke poring out the back that you can see.

other than that its a good idea with any engine not to push it too hard while cold. but you shouldnt have to wait till its on the half way mark.

how big is the turbo??? its not just turbo lag is it? has the car been doing this since you got it? or is this a new development?does it idle normal?

Edited March 18, 2011 by boiracer

[agentx]

wow so many replies in a few hours

Its not just running like cars run when cold - its 100% an issue. It idles perfectly fine, it started happening a few months ago all of a sudden, turbo was put in around 2 months before this. Its a TR43.

I really should look at the AFR's before replacing the o2 sensor yea? since if im running super rich, it can mess the sensor up again?

water temp sensor should be fine because the car shows correct temp and has a gradual increase all the way to half way?

[t_revz]

wow so many replies in a few hours

Its not just running like cars run when cold - its 100% an issue. It idles perfectly fine, it started happening a few months ago all of a sudden, turbo was put in around 2 months before this. Its a TR43.

I really should look at the AFR's before replacing the o2 sensor yea? since if im running super rich, it can mess the sensor up again?

water temp sensor should be fine because the car shows correct temp and has a gradual increase all the way to half way?

im only guessing/remembering but i thought there was a temp sensor for gauge, one for ecm, and a switch. maybe not...its late

[DVS JEZ]

Did u get a tune when u Put the new turbo in?

Sounds like the tune might need a touch up.

[blind_elk]

water temp sensor should be fine because the car shows correct temp and has a gradual increase all the way to half way?

There are 2 sensors - 1 for the gauge, and another one to tell the ECU what the coolant temperature is.

Really, you shouldn't be pushing the engine before it is warmed up properly (and letting it idle for several minutes first WILL NOT warm it up).

AND IT WILL HAVE NOTHING TO DO WITH THE O2 SENSOR!!!!!!!!!!!! For the 2,345,987th time, the ECU only reacts to the O2 sensor on constant throttle / cruise conditions. Under acceleration, the ECU ignores any input from the O2 sensor.

The engine is cold, it isn't working to optimium - live with it!

[Spark911]

my 34 gtt seems to hold back if you get in it and pot it around from the moment you turn the key. 5mins later - gone. remember these cars are nearly all 10+ years old - the systems/diagnostics (in standard ECU form) aren't as advanced as we once used to think they were

[SargeRX8]

my 34 gtt seems to hold back if you get in it and pot it around from the moment you turn the key. 5mins later - gone. remember these cars are nearly all 10+ years old - the systems/diagnostics (in standard ECU form) aren't as advanced as we once used to think they were

What the f**k? Any car Ive ever driven would be shit house when its cold. Take care of your car. No matter how new age or old school your car is, it still needs to warm up. Just because you run castrol GTX and that old man says you don't have to warm it up, does not make it true. Everything has a peak operating temperature, whether it be mechanical, natural or organic.

Another note to add is that the O2 sensor does not become active until a certain temperature threshold is reached. This is so the car can ignore the O2 readings while its warming up, and it just keeps adding fuel til its warmed up. A good idea is about 3 - 5 mins idle in drive way to get oil moving around then about 3 minutes of easy driving. After that your water temp should be around 50 - 60c and oil pressure should be a smidge under 4 at cruise speed and around 6 under load.

[rob82]

What the f**k? Any car Ive ever driven would be shit house when its cold. Take care of your car. No matter how new age or old school your car is, it still needs to warm up. Just because you run castrol GTX and that old man says you don't have to warm it up, does not make it true. Everything has a peak operating temperature, whether it be mechanical, natural or organic.

Another note to add is that the O2 sensor does not become active until a certain temperature threshold is reached. This is so the car can ignore the O2 readings while its warming up, and it just keeps adding fuel til its warmed up. A good idea is about 3 - 5 mins idle in drive way to get oil moving around then about 3 minutes of easy driving. After that your water temp should be around 50 - 60c and oil pressure should be a smidge under 4 at cruise speed and around 6 under load.

3-5min idle - f**ke that! Drive the car as if its a car, std engine or not. 10sec of idle is heaps to get the oil moving. Then drive the car as usual not hard until up to temp.

e

Now while the 02 sensor wont start working until about 50deg C what it learns in closed loop it will apply before the 02 sensor starts working. So if you have a f**ked 02 sensor and it learns the maximum fuel trim it will apply this correction when cold also. What is the eninge like when its upto temp? Does it use lots of fuel?

[agentx]

3-5min idle - f**ke that! Drive the car as if its a car, std engine or not. 10sec of idle is heaps to get the oil moving. Then drive the car as usual not hard until up to temp.

e

Now while the 02 sensor wont start working until about 50deg C what it learns in closed loop it will apply before the 02 sensor starts working. So if you have a f**ked 02 sensor and it learns the maximum fuel trim it will apply this correction when cold also. What is the eninge like when its upto temp? Does it use lots of fuel?

Yes I'm barely getting 6-7 km/litre. I didn't get a tune because I was a bit short of cash and I was running only 8 psi (yes i know i should get one asap). As for "living with it" just because its old, i refuse to believe that the skyline will just drive like this because its old / thats what they do when the engine is cold. This is NOT normal behavior, its not that its not running a 10 sec quarter when its cold, there is genuinely a problem. It feels like someone was pulling on the car in the opposite direction and then released all of a sudden when it reaches 2500ish rpm.

Sounds like the first thing I should do is get a tune and THEN sort the issue out (I don't think a tune is the answer, but it removes another problem that needs to be fixed before this).

Dr Drift - where are you

[Psymon]

My 32 used to do this when it was fairly stock. I just used to take it easy until it was warm and it was fine. It went away when I had it tuned to suit new turbo and injectors etc.

[ohno1]

car switches from cold map to hot map @ 60deg water temp

[Sarumatix]

Totally sounds like a stock RB20 tune (and my horribly tuned RB26 before I got a remap) with a bigger turbo on the cold start map. I have this too on an auto RB20 with GT2860rs) and the car hates driving at anything less than 4000 rpm. Checked with tuner and found that all parameters were safe. If you plug Consult in you will notice timing is heavily retarded during cold start at low revs. Let the car warm up and it will advance the timing and run fine.

This is the stock map, there are two solutions.. if you can live with putt putting around on cold start (the first thing I have to do in the morning is go up a large hill.. so I go up at about 30km/h) ignore it. Otherwise get your local reputable tuner to remap (cold start on my 26 is almost imperceptible now).

[RB25PWR]

My stock 33 does this also, the car just needs to warm up dude. Just grandma it until it's warm...

[bubba]

Sounds exactly like cold start.. it doesn't take long to get up to temp when driving so just baby it until it's up to temp.

If you're trying to give it beans when it's cold then you have no mechanical sympathy and shouldn't be driving a skyline.

[agentx]

I guess I still haven't explained it properly - I've been driving turbo cars for 9 years now, I'm not trying to drag race people when the engine is cold ... its NOT that its just running a bit off ... there's an evident jerk when i go over 2500 rpm THATS how much its being held back - you can sit here all day and say thats how skylines drive when they're cold but thats NOT what this is. It was driving perfectly fine when it was cold so for everyone who says skylines drive like shyt when they're cold - you need to get it checked out and sorted, because it drove perfectly fine till a few months back.

Apologies if this sounds a bit abrupt - but I can't make it any more clearer then this! Thanks alot for the helpful tips above though, will take it to get tuned first and then look for a solution.

[Tangles]

replace 02 sensor, clean air flow meter, install new plugs (bcpre6 $20 for the 6), check cold-start on dyno, retune!