Hello all, you may remember me from other fun threads such as "Is my timing out enough to cause no start?", but I am back once again to terrorise the motors forum and pick your collective brains. 
I'm having some further problems with my C3 Picasso, namely:
- Smoke from the exhaust when pulling away from lights / after idle.
- Not really any smoke when idle or at constant cruising speed. But pressing accelerator after idle causes it, pulling from lights, junctions, etc.
- Yesterday the car started to stall near idle revs (pulled up at lights and stalled by the time I came to a stop, couldn't get her started again).
- When the car did start again (after being pushed into a side street), it wanted to stall unless the accelerator was pressed slightly (1.5k RPM).
- When the car would not start it would crank and make a kind of "whoomp" noise at the end of cranking, sometimes it will make this sound when pushing smoke out, I think it may be misfiring.
- After a couple of minutes holding the throttle at 1.5k I was able to release it without stalling.
- Smoke in my opinion is a brown / grey, maybe a hint of blue though.
- Idle in general doesn't seem rough?
(Photos taken at idle, but after giving the accelerator a quick press to make smoke appear)
From what I can tell the problem gets worse once the engine gets to temperature AND driving around - for instance it can sit idle on the drive without stalling for 10+ minutes.
So far:
- I've replaced the PCV valve in case it was stuck open, no change. (Valve cover gasket also done before.)
- Checked PCV has negative pressure at valve cover, it does. Checked for cracks in PCV hose, don't think there is any.
- I've compression tested the cylinders to try and rule out worn piston rings, 175PSI every cylinder, dry test.
- Air filter hasn't been changed in 3 years but only has 15k on it, looks fine to me.
Questions:
- I've pulled my spark plugs and found that I appear to be running rich, can anyone confirm this is dry carbon deposits near the end of the threads?
- Also looking at this video you can see that there is a lighter portion on each insulator tip, is this bad spray pattern from injectors?
A couple of weeks ago this car wouldn't start because I believe the cylinders got washed with fuel, when I pulled the plugs diagnosing that problem they looked like better than now, no black carbon around the end of the threads (please ignore the oil deposits on these older photos, valve cover gaskets needed done and have now been done). But the smoky exhaust has gotten worse over the last two weeks. I am wondering if a rich condition existed before which caused my cylinder wash out a few weeks back.
So I'm lost as to where to go with this. I've taken some live data, short term fuel trim is 0% at idle (when there is no smoke), but ranges heavily between +/- 20% depending on throttle. I'll see if I can export the graph to a better format.
Anyone know what diagnostics I should be carrying out for all banks apparently running rich?
- Lack of airflow?
- Oxygen Sensors?
- Fuel Pressure Regulator?
Thank you!
I'm having some further problems with my C3 Picasso, namely:
- Smoke from the exhaust when pulling away from lights / after idle.
- Not really any smoke when idle or at constant cruising speed. But pressing accelerator after idle causes it, pulling from lights, junctions, etc.
- Yesterday the car started to stall near idle revs (pulled up at lights and stalled by the time I came to a stop, couldn't get her started again).
- When the car did start again (after being pushed into a side street), it wanted to stall unless the accelerator was pressed slightly (1.5k RPM).
- When the car would not start it would crank and make a kind of "whoomp" noise at the end of cranking, sometimes it will make this sound when pushing smoke out, I think it may be misfiring.
- After a couple of minutes holding the throttle at 1.5k I was able to release it without stalling.
- Smoke in my opinion is a brown / grey, maybe a hint of blue though.
- Idle in general doesn't seem rough?
(Photos taken at idle, but after giving the accelerator a quick press to make smoke appear)
From what I can tell the problem gets worse once the engine gets to temperature AND driving around - for instance it can sit idle on the drive without stalling for 10+ minutes.
So far:
- I've replaced the PCV valve in case it was stuck open, no change. (Valve cover gasket also done before.)
- Checked PCV has negative pressure at valve cover, it does. Checked for cracks in PCV hose, don't think there is any.
- I've compression tested the cylinders to try and rule out worn piston rings, 175PSI every cylinder, dry test.
- Air filter hasn't been changed in 3 years but only has 15k on it, looks fine to me.
Questions:
- I've pulled my spark plugs and found that I appear to be running rich, can anyone confirm this is dry carbon deposits near the end of the threads?
- Also looking at this video you can see that there is a lighter portion on each insulator tip, is this bad spray pattern from injectors?
A couple of weeks ago this car wouldn't start because I believe the cylinders got washed with fuel, when I pulled the plugs diagnosing that problem they looked like better than now, no black carbon around the end of the threads (please ignore the oil deposits on these older photos, valve cover gaskets needed done and have now been done). But the smoky exhaust has gotten worse over the last two weeks. I am wondering if a rich condition existed before which caused my cylinder wash out a few weeks back.
So I'm lost as to where to go with this. I've taken some live data, short term fuel trim is 0% at idle (when there is no smoke), but ranges heavily between +/- 20% depending on throttle. I'll see if I can export the graph to a better format.
Anyone know what diagnostics I should be carrying out for all banks apparently running rich?
- Lack of airflow?
- Oxygen Sensors?
- Fuel Pressure Regulator?
Thank you!
