Help T4 V40 cold start and idle

cwc2128 · Feb 3rd, 2008, 12:44

Hi recently picked up a 1998 T4 V40 drives fine , just changed the thermostat as the old one was stuck open and running cool but i still have the following prob

On a cold morning start it starts but immidiatly idles at 700 ish or lower and feels as though its struggling, when warm it still idles 700 ish but the dash steering wheel is vibrating, Im thinking temp sensor, if i unplug the idle control valve it throws the engine light and the revs drop to 400-500, when plugged back in it revs up then drops back to 700 ish, i have removed the throttle body and idle control valve and cleaned them thoroughly, any ideas, i can only think temp sensor on the thermo housing.

pyaap · Feb 3rd, 2008, 15:43

Have you considered the MAF as a possibility at all? They are known to fail and cause all manner of "weird" behaviour and erratic idling. Its probably an idea getting the ECU "read" to see if there are any fault codes stored too.

Clan · Feb 3rd, 2008, 15:48

give the throttle flap screw half a turn extra it makes the world of difference , it is a torx under the blue sealant assuming the throttle is perfectly clean inside

cwc2128 · Feb 3rd, 2008, 18:16

Screwed it now, checked the maf with a cotton bud and some alchol, one of the 2 wires was loose, now fallen off completely, car will not even start now, had to disconnect the maf and it runs but is sick..

Feb 3rd, 2008, 12:44	#1
cwc2128 Member Last Online: May 7th, 2009 15:42 Join Date: Jan 2008 Location: Surrey	Help T4 V40 cold start and idle Hi recently picked up a 1998 T4 V40 drives fine , just changed the thermostat as the old one was stuck open and running cool but i still have the following prob On a cold morning start it starts but immidiatly idles at 700 ish or lower and feels as though its struggling, when warm it still idles 700 ish but the dash steering wheel is vibrating, Im thinking temp sensor, if i unplug the idle control valve it throws the engine light and the revs drop to 400-500, when plugged back in it revs up then drops back to 700 ish, i have removed the throttle body and idle control valve and cleaned them thoroughly, any ideas, i can only think temp sensor on the thermo housing.

Feb 3rd, 2008, 15:43	#2
pyaap Non-T4 T4s RULE!!!! Last Online: Mar 29th, 2017 11:24 Join Date: Nov 2002 Location: Bristol / Bath	Have you considered the MAF as a possibility at all? They are known to fail and cause all manner of "weird" behaviour and erratic idling. Its probably an idea getting the ECU "read" to see if there are any fault codes stored too. __________________ "An Engine Which Runs Lean Lives on Borrowed Time" http://www.volvoforums.org.uk/showthread.php?t=13998 Last edited by pyaap; Feb 3rd, 2008 at 15:52.

Feb 3rd, 2008, 15:48	#3
Clan Experienced Member Last Online: Yesterday 23:47 Join Date: Jun 2007 Location: L/H side	give the throttle flap screw half a turn extra it makes the world of difference , it is a torx under the blue sealant assuming the throttle is perfectly clean inside __________________ My comments are only based on my opinions and vast experience .

Feb 3rd, 2008, 18:16	#4
cwc2128 Member Last Online: May 7th, 2009 15:42 Join Date: Jan 2008 Location: Surrey	Screwed it now, checked the maf with a cotton bud and some alchol, one of the 2 wires was loose, now fallen off completely, car will not even start now, had to disconnect the maf and it runs but is sick..

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