Emissions problem

[mikeday]

New TDP convert here. 94 Blazer 6.5 TD since new with only 102K on it; :confused: stock to now. Unique SUV that fits in the garage and tows the horse trailer nicely. Last month failed the first CO emissions (opacity) try. Shop remedied by "cleaning the passages in the induction system". I found TDP and have already cut out the snorkel and changed the (original) glow plugs. Have new EGR and CDR valves to install and am doing a new exhaust system (with gutted cat) this week. I haven't seen my emissions issue discussed anywhere and wonder if anybody has any ideas.

[Hubert]

Its been discussed either here or the other two popular websites a few times.

You will see some improvements with better air flow, clean filter (aftermarket filter maybe too), fuel additive etc. Might have timing checked and adjusted to optimum. Waste gate check too. I am not familiar with 94 do they have vaccum pump or spring wastegate somebody else?

It makes a pretty big difference how the technician actually performs the test. If they are flooring it from idle quick its a tougher test than slowing the right foot down some. Might try a different test site.

If you are more than a little over the limit then biggest gain will be new injectors. They start declining in performance between 80-120K miles. I read one post where new injectors made a 30 something % improvement on the opacity test.