Car Only starts while holding accelerator on? VX

[kylo33710]

Hey my mates VX recently started idling at like 500rpm but stil staying on, sounding like it was running too slow though and sometimes stalling when put into D or R. (only when cold)
i got in it and tryed to start it and if i pump the gas it will start and then straight away konk out but if i hold it at 1000rpm it will stay on and once it's warmed up it goes back to idling at normal. and will start completely normal so this only happens when car is cold (in my town cold is 28 degrees) what could this be? thanks in advance guys

 

[kylo33710]

any ideas? car seems to be fine now except it still idles low around 400-500rpm

 

[acarmody]

I would start with the IAC and see if its sticking.

 

[Not_An_Abba_Fan]

Also check the purge hose under the throttle body, they get hard and fall off.

 

[acarmody]

Also check the purge hose under the throttle body, they get hard and fall off.

Nope...........they just fall off regardless of the condition. Holden skimping on a 5c hose clamp.

 

[s_ikari2015]

if the above two (Idle Air Control valve and purge hose) don't fix it, then remove the engine control relay in the fuse box and the main fuse under the steering wheel. Let them sit out for a while then put them back in. This should make the ECU recalibrate to all the sensors and might fix it.
Also if your mate has recently put in a "tuned chip" in the passenger foot well, or changed the computer, then put the old one back in. This may also fix it as it could be a bad tune.

 

[kylo33710]

cleaned the IAC and it was ridiculously gunky, got most of it out but couldn't get more out because i didn't want to touch it and move it, didn't fix it though. i will check the purge hose tomorrow aswell. car is also clunking into 2nd sometimes at low load and it makes a ting noise, or when putting accelerator on all of a sudden.. :/

 

[NickVR]

Do you have to hold the accelerator flat to start and when it does, black smoke puffs out the back? Mine did this (buick motor though), had a crap idle and died occasionally too. Coolant temp sensor was the issue for mine. If nothing else works try that.

 

[kylo33710]

no just blipping the throttle will start the car and it will stall unless you hold it at about 1/4 throttle and then eventually it stays on. cleaned IAC, TB, cleaned intake manifold, checked that tube and it's all good. i am yet to try: Remove relays to reset ECU sensor readings, check spark, alternator, CAS and CTS will be the last thing on the list we will see how it goes.

 

[VTSSDUDE]

IAC valve by the sounds of it. Does it start with no accelerator pressed when the car is warmed up?