Power loss once up to running temp

[DirtyE30]

hi all,
have a early 90s 1uz in a e30 bmw, manual 5 speed using 40 40 40 pin ecu.
all in all engine runs pretty good, doesnt throw any fault codes.
but i noticed it seems to run a little better when cold (driving). the motor runs pretty good but never perfect and tonight i was trying to work out why it runs better when cold.
I got a spare ecu temp sensor i had and pluged it in and left it external to the motor (just sitting on top) to see what it would go like and f**k what a difference! so much more throttle response, low and high end power! i couldnt believe it! only problem is it still idles high like its cold (obviously) and is not really a "fix" to my problem.

any ideas?

cheers,
buck.

 

[sideshow]

Have u tried not going full throttle off the mark
I always found the 1uz to go better with half throttle
Then gradually give it more
Maybe u have sheit cold air intake
Maybe it's the diff ratio
U can always hook up a relay which switches between the two
Temp sensors at idle to full throttle
U might have other issues but it's common most cars go better
When cold as they run richer
Newish cars have been anal probed by the good old fking
Greenies to make the world a better smelling place
So they make the motors run lean and hot as fk to make emissions
Low
Maybe I would borrow a stock std Lexus with 1uz and try doing
The water temp swap trick on it
If it runs better than what u have found is true
If it doesn't have much power difference then maybe u have an airflow
Meter issue or something else wrong
But u need to try your trick on a std setup lexus or Toyota
This way u have something to go by

 

[samsdad]

I have 3 doing this ATM and one is my own (90 Surf with 91 UZZ31 Soarer engine and ECU) the other two are a stock 1993 UCF10 LS400 and a 1999 Hilux with UCF21 Celsior engine and ECU. Our former workshop loan car which is a 1991 UCF11 Celsior (lent to a customer but money came back rather than the car as his wife loved it) is not doing this. So as an experiement we got a UCF11 ECU (fully refurbished) and fitted that to the LS... No difference. On my Surf and the Hilux larger fuel pumps have been tried with no change along with changing air flow meters etc. All have new caps, rotors, plugs, leads, O2s (both sub and main) and fire no codes. All once warm seem to miss and stutter below 3000rpm with no power yet once above that perform like a cat off a hot tin roof. All when plugged into the scanner on Data show lean mixture as well. Running 91/95/98 octane fuel makes little difference and they seem worse on 98. It's almost like they're going into "Knock mode" and pulling the timing back. So that brings the question. Is the fuel quality a bit wanting? or do we have a collection of UZs with faulty knock sensors?

 

[sideshow]

arent i fking glad i dont do much diagnosing on these 1uzs since ive moved heheheeheeh
i dont have access to the parts like it did at sss heheeeheh

 

[samsdad]

Yeah rub it in... Not to sound rude but you must be like a "pig in sh!t" now without all the stress. Hope things are going well for you

 

[sideshow]

yes im not making much money but my body feels relaxed heheheh
slowly getting more work fixing stuff not many can do
just need to figoure out the shops that pay and ones that dont pay hehehehe

 

[samsdad]

I hear ya. My body is starting to pack it in after 25 years of "spanner chucking". Couldn't even pick up a cup of coffee last sunday and the beer later in the day.....

Time for something new