Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk1 2002-2008 => Topic started by: Multiplier7 on May 07, 2026, 10:00:34 AM
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Hi there,
our Honda Jazz 2007 has failed emissions tests, with the shop saying it smells like burnt oil. The Co was about 0.7, the Hc 300-400 and the lambda value a bit over 1 (so the Co and Hc indicate a rich condition and the lambda a lean condition.
When we took the spark plugs out, they had some oil on it and a white tip. We then put a camera into the cylinders and there was some oil on top of the pistons as seen in the attached image.
We have tested for vacuum leaks, exhaust pipe leaks, the EGR valve, the catalytic converter, changed both lambda sensors, changed the air filter, and the throttle body and intake manifold. All seem fine so it seems more likely that the issue is inside the engine.
Can somebody point us in the right direction as to what the problem could be and why oil would be getting into the cylinders/onto the pistons? Could it be the valve seals/ piston rings?
Note that the car drives and sounds quite fine, but the exhaust fumes have been smelling rich with petrol but there hasn't been black smoke coming out.
Any help is greatly appreciated!
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These things may or may not be related, but the first thing to do is to try and work out the oil issue.
As you say, there are normally two main ways oil can get into the combustion chambers. It either comes up past the piston rings from the oil in the sump or it can leak down the valve stems from the camshaft carrier.
It's very unusual for a Jazz to be burning oil unless it's very high mileage or has questionable service history with infrequent oil changes.
A compression test on each cylinder would be a good place to start as it might give a clue about how good the rings are.
In general, if a car is burning oil, the exhaust will have a blueish tinge to it, black tends to indicate too much fuel and white tends to be coolant.
Does the car use any oil when checking the level on the dipstick?
When doing a compression test, take one plug out of each of the cylinders, then screw the test gauge into just one. Crank the engine perhaps ten times and see what the pressure rises to.