Re: hydrocarbons excessive fail
Posted: 19 Jul 2013, 22:53
The MOT tester pointed out that my 1.9 petrol had high HC, not a fail but he said it was running a bit lean to cause this. I compared with last years certificate and the HC had doubled despite barely using the van all last year.
After reading this and other threads I changed the servo hose both sides of the non return valve. The old hose looked a bit dodgy at the ends by no obvious damage.
I don't know if the HC has been improved for sure but I suspect it has! For ages there was always a bit of an fuel/oily smell whenever I got out of the van. The fuel lines are all good so I'd always put this down to a bit of oil from leaking pushrod seals creeping onto the exhaust and burning off.
Since changing the servo hose, the smell has suddenly gone! No doubt most of the fuel going into cylinder 3 was going straight out unburnt so I'm hoping to notice better economy too... It's convinced me to check and replace all the other vacuum hoses.
One question, the original servo hose was steel wire reinforced with quite thin walls, the one I bought was thick walled rubber and wouldn't fit the manifold connection. So at the moment I'm using a short length of stout heater hose from manifold to non return valve. The heater hose probably has strong enough walls but is there anywhere that supplies proper thin walled servo hose?
After reading this and other threads I changed the servo hose both sides of the non return valve. The old hose looked a bit dodgy at the ends by no obvious damage.
I don't know if the HC has been improved for sure but I suspect it has! For ages there was always a bit of an fuel/oily smell whenever I got out of the van. The fuel lines are all good so I'd always put this down to a bit of oil from leaking pushrod seals creeping onto the exhaust and burning off.
Since changing the servo hose, the smell has suddenly gone! No doubt most of the fuel going into cylinder 3 was going straight out unburnt so I'm hoping to notice better economy too... It's convinced me to check and replace all the other vacuum hoses.
One question, the original servo hose was steel wire reinforced with quite thin walls, the one I bought was thick walled rubber and wouldn't fit the manifold connection. So at the moment I'm using a short length of stout heater hose from manifold to non return valve. The heater hose probably has strong enough walls but is there anywhere that supplies proper thin walled servo hose?