ok i know tthis has been touched many many times before but I like to ask so maybe some new information comes to light,,,,,,

I know for a fact from cold start I should get 1500 rpm then as it warms up settles down to 950 rpm or as discussed with Sabre we will re adjust back down to 850 , i like my idle low as my hayward and scott exhuast is really loud and deep and just vibrates the shit out of anything glass or residential lol (so sorry but i love it) HOWEVER - recently having tried 3 different plastic RS inlets

- i am stuck on 2000 rpm cold start - so you tunr the key it revs up 2000 rpm then splutters at 750 rpm then levels out - i mean it sounds kool lol lke a rally car (any temp below 50 Celsius via scangauge) which is effin loud if i have to pick up my daughter from work or uni late , just wanted to know what controls the cold start - i had it perfect briefly but after 2 X 20 mile drives no boost it seems something has worked loose again but wanted an opinion - ie that barometer would that affect idle? Another thing i have noticed , if say its still warming up ad i , say, start to roll out of the drive, the car senses movement and then lowers idle, ive had 3 / 4 different RS ecus and this is the only one that does it - sorry many angles of info here lol ----- does the speed sensor affect idle?

Runnin larger big mAF SO that can be ruled out -
Tried different new Lambda sensor , tried genuine one and euro carparts no difference
Secured all vacuum ports and i mean properly EVEN a hoseclip on the PCV valve lol
New inlet gaskets < new throttle gasket,
Even bought an o ring splicing kit and made a gasket between inlet and throttle adapter
Tried 2 new Throttle sensors new and genuine
Though maybe rail is leaking , changed o rings etc , no change...
Exhaust downpipe not leaking either end....

There was a rev hangup between gears but that was the power steering loom which is now sorted and is good between gears ....

Before i sell it ...or try a Metal inlet any ideas loool ??? cheers people ...

The only thing i can think is im not torquing the inlet properly and working loose - i mean for example - @big_wasa has that RS engine running on a engine stand ... look how nicely it idles loool wyhy cant any of my focus be like that......

I had ONE ecu about 3 years ago which i used to convert my T230 from Pectel to Ford RS Ecu and that was perfect but my engine and turbo was shit so sold it all lol - shud of kept it ...maybe its the AE AF map thingy?

 

Lambda isn’t used until it’s warmed up and goes closed loop. Again, it’s not used at Wot either. With your big maf, have you checked your Iat are sensible ? Both in the maf and the inlet elbow.

But air leaks are the most common cause of poor idle. The revs going up and down is called hunting as the ecu tries to get the idle as low as it can.

Classic poor idle causes.

Gummed up idle control valve, they seize up. Not that likely but I’ve had one.
The crank case vapour recovery hoses split, Very common.
The check valve in the recovery hose stick.
Pcv valves stick.
Brake servo diaphragm leak.
There is a blanking plug on the ports on the back of the manifold. These perish.
Reference hose for the Fpr.
Reference hose for the map.

You Can blank these of one at time to see if it changes anything at idle.

Dirty injectors dribbling.

Have you had your fuel pressure checked. Pump or Fpr could be dropping pressure.

Re torquing the mani, being plastic it only needs nipping up.

And then there is the Mapping. What spec are you running to need the big maf ?

Shame your not local mate.

 

You also have load switches that up the idle. Ac, power steering, clutch, heated front screen but it’s only a small amount. Not 2k idle

 

yeah it just seems it sucks in air hence why it goes to 2000 rpm HOWEVER i may have solved it - i will test later today once ive done the thread on my cylinder head which i effed up myself - chasin an oil leak - ,,,,as my mate says - I am my own worst enemy especially with cars ...

Thanks for the replies...

Oh - almost everything is new - Injectors about 6 months old maybe a year max

Running larger maf to obtain desired boost and fueling , ratios etc ( not my forte ) spec is Area six 420 hp zetec -Forged rods , pistons , arp conrod bolts, gas flowed/ported head , i think but def ported, uprated valves and springs , uprated area six inlet cam and a wee little original slightly uprated turbo at 24 psi, FMIC , DW Fuel pump , Sachs clutch, Clutch plate / Flywheel lightened and balanced.. 420 bhp on Sabres rollers...

All other vacuum hoses are tight and secure - did the carb cleaner spray thang and no idle change -- BUT AS ABOVE I am hoping will be ok today-- as i think i may have found the problem which cured it straight away - but i have had this before - and then after 2-3 starts goes back to 2000 rpm ....well what i did was check the main earth from battery to bulkhead / chassis whatever you call it and sometimes we move it due to FMIC and moving battery etc...well that was just on paint lol ...i need to check all my other earths,,,,but was idling perfect....will test later fingers crosssed....sorry for shit grammar - style of post , if it hurts yours eyes looool

Ive tried about 6 different idle valves - done the cleaning thing, tried a new After market one that cost about Ł70 german make...

 

420bhp should be a handful

 

Removing the ecu earth will re set the ECU. It then needs to re learns it's parameters.

That's why the problem comes back after so many cycles.

 

made a steady jump - had t230 for about 15 years - ran good for only 4 of those lol with about 210-240 bhp again depending on rollers - then Focus t250 - now that was a fast car - said to have 250 bhp but i swear its quicker! And now my current Focus rs - was in limp mode for a year without knowing - got remapped to Sabre 340 then recently with forged engine at 420 - happy just need to concentrate on cosmetics now,,,general maintenance and want to eventually make everysingle hose aeroquip/braided -an fittng...