R.I.P Allan Simonsen
AO Silver Member
Join Date: Dec 2007
Location: United Kingdom
just tried a cold start, no smoke. revved engine, and again no smoke, so I can only guess it was a freak PCV problem. the engine on the cold start cycle dropped down to a smooth even 1000 rpm idle almost immediately, and the engine turns over evenly on the starter, so I don't believe its jumped a tooth on the cams, and also the belt is running true on the pulleys.
I tried diagnosing the idle issue bu unplugging various sensors, and got the following results.
lambda - no difference, plugged in or removed
MAF - no difference plugged in or removed - set injection light when unplugged
Coolant temp sensor. - difficult to start, idled about 300rpm for a moment, then died. no injector warning light.
I'm wondering if perhaps the CTS is starting to go out of range, perhaps causing a slightly over rich situation at idle (the idle miss / chug does sound like a rich mixture) though no black smoke, or fuel smell.
is it possible the rich idle has caused a little bore washing, hence the puff of smoke? its only done it once, with a smaller puff the second time, and never before or since..
As they are so cheap, i'm going to replace both of the PCV valves and oil separator can, just to eliminate them.
the other thing that nags me it may be a sensor going out of range is that the problem has gradually come on, and economy dropped off over time. i have kept the old plugs, they are a little dark, but they are all dry, deposit free, and all the same colour (more chocolate than rich tea colour)
Last edited by philoldsmobile; 20-03-11 at 13:15.