High Idle when warmed up

[jagonza]

i have a 1977 124, it starts easily and will idle very smoothly from a cold start. it will idle around the 800-900rpm mark cold.

again it starts cold and runs cold very smoothly no issues.

after it comes up to temperature the idle will move up to about 1500-1600rpm and settle there. At this point it still runs very smoothly under load. it does "smell" a bit rich but i cant be sure.

I was going to adjust adjust the idle screw to get down to about 850rpm, is that the right thing to do? or should i adjust the idle mixture screw first then the idle set screw. I have read Artigue's guide , but am not sure which way to go.

my fear is that i have an otherwise smooth running engine and i do more harm than good.

the car has been heavily modified by the PO, electronic ignition, 9.8:1 Compression, no smog pump, no cat, "mild cams" ( whatever that means), "meaner cleaner",

thanks in advance for any help and yes I am a new Fiat owner. I would love to meet up with anyone in Atlanta learn more

[vandor]

Sounds like the choke is not disengaging, or it is not working well and the PO adjusted the idle speed high, so it does not stall when cold.

[jagonza]

thank you for the reply.

I took the air cleaner off and manually pulled the throttle cable with the engine off and cold. the choke snapped shut , i then took it for a drive to get the coolant hot and checked on the choke and it was at least half way open ( i am not sure what full open looks like) after about ten minutes of driving on a 45 degree day. i would guess the choke plate was about 50-60 degrees open - I am not sure if it should be a full 90 degrees open.

i checked the vacuum lines and most of them are capped. i did see one that went to a plastic box about one inch square that is under what i think is the Fast Idle button on the fender. that box had a another fitting that was broken off. not sure what that little box does ?

i did find some lose wires but they dont seem relevant based on the color code for a 1977. however my 77 has the relays under the hood like a 76, so maybe i need to look up the 76 wiring color code ??

[klweimer]

Hi Jagonza,

You really need to go to Brad Artigue's website, where he has all kinds of great info for Fiats. My favorite item is his FIAT 124 Spider Engine Modification and Maintenance guide. Brad is also a regular contributor on this site and recently released a book (available on Amazon) that is a perfect place to start after buying your first Fiat.
http://www.artigue.com/page/2/

Kirk

[jagonza]

yes Artigue site is amazing, he is very valueable !

[jagonza]

so it looks like the fast idle screw need to be adjusted, not the idle screw underneath but the fast idle screw above was adjusted so far it did not allow the normal idle screw to come into play.