Lumpy Cold Idle

1st October 2010, 22:29

Hi,

First off, I've had my car for about 3.5 years so am well aware that the cold idle on a VTS is far from perfect

However, recently it has been considerably lumpier than normal. For about the first couple of minutes it sounds like it's running on PH3's (unfotunately it isn't) and after four or so minutes it eventually smooths out.

The heater element on my primary lambda sensor is faulty so this may be the issue but has anyone got any other ideas what may be causing shite cold idle?

Thanks in advance

1st October 2010, 22:58

a temp sensor maybe?

also the heater element went on my lambda too not so long ago and my cold starts wernt the best and i watched it on the diagnostics graph/readings aswell, and it was appauling when cold, then when it warmed up the graph/readings went to how it should be and it ran fine
luckily it was still in its warrenty period so i swapped it over, and cold starts improved quite a lot and was fine after that

so if you know thats at fault maybe start there, rather than change sensors which make no difference to then change lambda and find that cures your not so good cold idle/start so then youve spent money you didnt need to

hope that helps

1st October 2010, 23:40

Excellent info! It would marry up nicely that when the Lambda is cold the reading is way off but as it heats up naturally with the exhaust gasses the reading improves!

I'll replace that first

Cheers.

2nd October 2010, 02:41

my vtr has em light on, i know its lambda(just do) also failed mot on emissions, my cold start is lumpy as fook atm, id imagin this is your prob tbh, the mornings are cold now and it takes alot to heat engine bocks up once they drop down in night time temps