TurboCharged 1UZ : hesitating while accelerating

[jessy]

Hi everyone,

I am in the process to finish my 1UZ TT swap inside a 240sx S13 with a HKS map, but I have a little problem, and I would like some experts to help me if possible

Here is the thing :
My 1UZ is turbocharged (twin turbo, TD05 from Mitsubishi) and I have a TPS from a Q45 Nissan.
My engine starts up without any problem, and idles at around 850-900 rpm.
When I try to accelerate, I can see in the datalogging the TPS position increasing (in % of opening state) but then engine hesistates a lot, and doesn't know what to do
If I go like idle state/full throttle all the way, it accelerates well but then hesistates again...

Besides, the water temperature is indicating 130 degrees Celsius all the time !

So I tested with a multimeter the water temp sensor (I tested it at the pins of the sensor, and at the wires coming into my ECU) :
It indicates 2.42 kOhms when cold and is going lower when engine gets hotter.

Which values should I read from this water temp sensor ? (it is the green one, 2 wires sensor )

This might be the source of the problem, but I am not sure of it, it is just that this doesn't appear to be normal to me...

Thank You in Advance for your help

 

[Lambo]

1UZ temp sensor

hi Jessy, this is from a sc400 1992 manual it should help

Regards
Lambo

 

[stevechumo]

Are you using original Lexus MAF for the 1UZ?

 

[poweredby1uz]

same as above?

Do you have any pics?

 

[jessy]

@Lambo : Thank You very much Sir ! This points out exactly what I was afraid of : my sensor is working as expected ...

@stevechumo & poweredby1uz : I do not use a MAF sensor. It is actually managed by a MAP sensor and Boost sensor.

Here is pics of the engine setup in my car (some vaccum lines are missing in the photos, this are some early shoots of the swap) :

My HKS ECU is indicating 130degrees when I am connecting the water temp sensor to the ECU and 0 degrees when I am disconnecting the water temp sensor...
Values taken at the wires going to the ECU are as good as the values taken at the pins of the water temp sensor.

When disconnecting the Water temp sensor and accelerating, the same hesitation occurs... So something else must disturb the ECU... I still have to figure this out... But I have no clue so far...

 

[jessy]

Some news :
I replaced the water temperature sensor, but still not get any values at the ECU...
Though, I discovered that there was a line coming out of the throttle body that was a vacuum...
I have seen this diagram :

I capped the vacuum coming out from the Throttle body. (don't know if it is good to do so though...)

Now the engine is accelerating quite well when accelerating slowly.
But when I go from totally closed to wide open throttle, engine hesitates and does not accelerate well.
Besides, I have noted the AFR in both cases :
When accelerating well, I am between 11.2 and 13.9
And when it hesitates (strong acceleration) I am at 16+. That indicated that my mixture is lean at this moment.

But there is my question then : what should be my fuel pressure at this moment (strong acceleration )?

In idle mode I am around 40psi at the fuel pressure regulator.
When accelerating it goes up to 45 psi.

So now I have two leads : vacuum misfit, and not enough fuel providing...

Any ideas ?

 

[stevieg]

Get it tuned!

 

[jessy]

The fact is : it is already tuned.
I have a HKS Fcon V Pro (vers 2.1) ECU, and I have the program to read and write the program.

Here is my engine getting mapped by my friend back in Bangkok :

[video]http://www.youtube.com/embed/GZALILL0SZw[/video]

Engine was running fine.

Here is a video after mapping :

http://www.youtube.com/watch?v=J635iKNVUEw

I should post some videos of my current running states so you can see what happens...