Cold start idle speed

[Patrol 1993]

I have a 93 model 4.2 liter fuel injected petrol Patrol.
When I start it from cold the engine revs up to 1200 rpm for 5 or so minutes until it warms up.
I am not familiar with the way it is meant to work but 1200 rpm straight from the start seems a bit fast for an engine that is cold.
Is this normal? if not what should the engine rpm be on cold starts.
Do I need to adjust it and how is this done?

Any help is appreciated.

Thanks Neil.

[Bigcol]

it will be the choke, that adjusts it to run richer, to help bring the motor up to operating temp

1200 does sound a tad high, I would have thought only about 300rpm more than idle

if you have a long piece of tube, when you first start it up, put one end in your ear, and with the other end, stick it around the inlet manifold and such, see if you can hear any "sucking" noises
might be a vacuum leak, making it rev higher.....?

[Patrol 1993]

Hey Bigcol,
Tried the hose / tube idea and all I could hear is engine noise.
Thanks anyway for the suggestion.

Neil.

[Bigcol]

well, thats got me stumped,

being fuel injected, makes it harder for sure

have you taken the MAF (Mass Air Flow) sensor out and cleaned it? - it may be thinking its not getting enough air until warmed up
you need the proper MAF cleaner (some say its about $30.00 from suprecreep) but it will last a long time

[no eye deer]

Mine runs at 1100 rpm at first-when cold.

[Bigcol]

how long for no eye........?
2 or 3 mins, or longer?

[Patrol 1993]

I wonder if there is a listed RPM the engine is meant to run at when cold?

[threedogs]

My 3ltr Di has a fast idle switch, it revs at 1200 rpm
Do the petrol have similar ????

[Bigcol]

Im not sure TD, as my old GQ with the TB42 was a carby
never got around to thinking about putting fuel injection on it

[no eye deer]

Yeah BigCol, about 2-3 minutes. Its in pretty good nick, so guessing it's normal.

[Patrol 1993]

Hey Threedogs,
Where is the fast idle switch.

Neil.

[Patrol 1993]

I rang my local Nissan service center and they said that 1200 rpm sounded okay.
That other vehicles had a cold start rpm of 1500 or more.

Neil.