Strange loss of performance until 1/4 throttle when cold

[Cubes]

Usually when I first start mine in the morning it feels a little dead (like a flat spot) unless I give it a decent amount of acceleration.

Funny thing is when it is feeling dead boost also comes up quite quickly but doesn't appear to make the car go at all then I press the accelerator just that little bit more and it starts accelerating decently with a ever so slight hessitation. During this in first and second I can see a bit of smoke swirling around the arse end of the car in the revision mirror it looks like a real dark grey colour I can also almost see the black. Fuel?

This morning I didn't want that fuel cloud behind the car as a copper was right up my clacker as soon as I pulled out the drive way.

So i took off real slow not hitting boost in first or second and the car felt really dead..

Cruising on 60km's it requires more than normal acceleration when cold for some reason but this time maybe because I didn't blow the crap out by hitting a little bit of boost and making the cloud it started to miss and caugh.

I had to accelerate to just past 1/4 to where it started to take off and made the cloud a little.

It was then fine but still with a small flat spot or dead spot that can actually make the car make boost when cruising.

Any one have any ideas? AFM maybe?

The cars idle does bounce ever so slightly.

[002 NVS]

My R32 felt the same, only when you first take of in the morning...

Do you let the car heat up for 5 mins or so before you start driving??

I doubt it is a problem?? if so can't be anything serious as mine did the whole time i had it...

I never used to bring my car onto boost until the temparature was up to where it normally is anyway, but it was definitely sluggish when u go through the gears, and seems to hit boost faster once you get to a certain point.. I didn't have any smoke though??

[gtrhybrid]

your car is in close loop which runs it really rich and allsorts of other stuff to be safe on cold internals. Notice it will snap out of it when the temp guage is 2/3 the way to normal operating temp.

[Cubes]

It is getting way worse now though and is starting to blow dark grey/blackish smoke in the revision mirror.

The smoke doesn't seem to be as bad when I warm it up for 5 mins or so but I can't always warm it up especially when its been sitting at uni for 5 hours then I need to jump in it to move to the other side of the uni find a car park and have 10 mins to do it..

Its not just in the mornings but the mornings it is at its worse.

I replaced the thermostat with a VL RB one that was dodgy and wouldn't close properly so it caused the car to constantly run near the cold line. I then cracked a top radiator tank so i sent it in to get fixed. I also bought a genuine RB20DET Nissan thermostat. When I got the car back it would sit on the same temperature.

The difference is now that it has the traites of a car without a thermostat or a car that has a thermostat fully open as in the hot weather on idle with the aircon on it now slowly creeps up to hot. I.e the water is flowing to fast to be cooled.

So.. When I rip the motor out in a month or two i'm going to check it then go back and blast the hell out of the idiot that said to me when i called back and enquired "Oh yer i remember that as the bloke fitted everything up then i walked past and saw it sitting on the dash, so i said to him he had to rip it all off again and slap it in" My guess is he may have done that but the bloke thought.. fark it, where's the nearest bin.... its near 5pm. which it was.

but yer it does snap out of it once a few kays down the road but its starting to blow a hell of a lot of black smoke in the morning and if i don't make it hit boost and blow the smoke out it makes it run really really bad to the point where it is missing constantly.

oh yer.. Closed Loop mode is when the car is cruising or idling or light throttle even and it leans out the mixture depending on the car right up to 16:1.

[WazR32GTSt]

i don't know about the smoke symptom, but as far as the hesitation when cold i USED to have this problem.

Q) How did i fix it?

A) my one of my knock sensors was unplugged! how stupid... so i plugged it back in, reset the ECU, and problem solved...

check your knock sensors or run an ECU diagnostics...

[Cubes]

So where abouts is this knock sensor?

[MetBlue_GTST]

Joel, your still running standard ECU right?? Well by the sounds of it, the car is running rich while the engine is warming up... Generally when engines are cold they require more fuel to get them going, then when you plant your foot, the AF ratios will be rich, hence cloud of smoke... Thats what it sounds like to me anyway...

[Cubes]

Yer I am running the stock ecu and a Bosh 910 pump. I may end up running twin Bosh 910's or just a single Bosh044. The noise of the 044's is what puts me off however.

I might try disconnecting the external bosh fuel pump and see if it makes anydifference. BUT it is running inline after the stock fuel pump so will that cause any flow restrictions to worry about.

Before I slapped the pump on it was still running mega rich up top and would still pick up around 15rwkw by tuning the final af's to around 12:1.

It does worry's me as I'm dropping a rebuilt motor (3ltr) in it soon and the mega rich start up is bad for the run-in as it washes the oil off the nice new honed bores.

That has cost me close to 2k for the head/work and around 3-3.5k for the bottom end.

[BOOSTD]

haha, I know what it is-mine does the same thing. Fuel mixtures are wrong untill the Oxy Sensor heats up and allows the ECU to go into closed loop and control the mixtures.

[Cubes]

ahh so the pre-heat is nacked on my o2 sensor possibly.

[Steve]

Joel, I have heard alot of guys mention that when they put an aftermarket or larger fuel pump in the car starts running a bit richer. Perhaps that is why it is worse than it was before?

Also, as your car may be a bit richer than normal, it is possible that the plugs dont like it? When was the last time you had a look at them? and if you need some NGK bcpr6es plugs I have some spare coppers sitting in my garage that you can have as I have just had mine upgraded to platinum 7s. They are in good cond and free to good home:)

Perhaps its a combination of a few things adding together and making the whole outcome worse.

[BOOSTD]

yes, my car ran richer with my new fuel pump.

[gtrhybrid]

to check the smoke start your car when cold and when It is smoking go and smell the exhaust and if it smells like gas your having richness smoke. If so then you might have some bad sensor like afm or o2 for example thats making you run extra rich.

[gtrhybrid]

knock sensors are on the block under the intake maniford. One listens for cyls 1 2 and 3 and the other listens for 4 5 and 6. Kind of a bi**h to get too.

[gtrhybrid]

Probably not the knock sensors unless you have a check engine light.

[Cubes]

I've had the fuel pump on it for some time now.

The problem has got worse since I changed my plugs which was less then 5k ago. Previously I had the bcpr6es but they had the v groove in the electrode i think it is. This time round I wasn't able to find any one the standard electrode. I slapped them in and instantly noticed a loss of power with a slight hessitation.

I had to drop the timing right back to standard for it to rev out nicely without falling in to a hole.

Maybe I just got a slightly dud plug in there that is playing up a little. I might just play it safe and put the new motor in after i've replaced the afm with a z32, replaced the o2 sensor and got the powerfc in there. Then get it run in on the rollers with a light tune.

I've also noticed since i've been running coppers that the idle isn't as smooth as the plats. Unless that is the nature of the slightly colder plug?!?

[Roy]

I think the colder plug is whats causing the rougher idle...

...and my thoughts are the RB20 is simply playing up as it knows its off to the dog house when you betray it for a heavy breathing 3.0L RB.

It must feel so betrayed after taking all those whippings from its master not to be rewarded with a big bad turbo:D

[rb20-calais]

lol

[adam 32]

i had this same problem, and it got alot better when i changed the plugs and cleaned all electrical connectors ie AFM, TPS, Coils and Ignition module...

but yeh it always goes away once warmed up, but got so bad i couldnt even drive the car when it was cold! the exhaust had a much louder drone to it and there was no throttle repsonse around 2000rpm. sound like the same problem youre having - im not sure exactly what fixed mine, but thats what i did...

[Cubes]

Yep thats it adam... the exhaust does go a little louder and the turbo starts spooling but nothing happens.

Lol Roy... I'm getting a powerfc before the RB30 goes in so i might plug it in and see how the stock settings on the powerfc run.