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.

[turbovair]

Last year I failed here in Phoenix. My opacity limit is 40 and I exceeded it.Having 130,000 on the original injectors, I elected to replace with units purchased from JK.Then, I had my timing re-set at the dealer. My opacity dropped to 6.5 and I passed(total cost about $500)

Yesterday, I went for this years test. I purchased a new air filter and fuel filter at NAPA for $50(ouch!) Went down for the test and they had problems with the test equipment and issued me a "directors certificate" which is an automatic PASS. I chatted briefly with the tech who indicated my readings(the ones they could actually get) were around 33.HUH?

So,I am happy to pass and get another year out of this truck, but what about next year? Will I need to replace the diesel pump? Repair the engine?(valve job?)This truck seems to get harder and harder to pass every year.I take very good care of it and dont abuse it.This has me looking at replacing the truck very soon.

[Bnave95]

Try using Power Service Diesel Clean in the gray bottle at double the rate. Make some short hard runs before testing then check. Injectors could be a big issue and dont know if you use any additves. Air Filters should always be changed or cleaned if you have a washable one before testing. Having extra boost helps. Hopefully they do a roll on test. Turbo needs to spool up and build up psi. None working EGR could be your problems also.
Let us know how you come out,what you did that helped to pass.
Some day someone may want to do a search and will see your post ;)

[turbovair]

Oh, I forgot to mention that its a "snap test" here in Phoenix.Idle to full throttle and back again. I was watching my boost. It would rise to about 5 initially and settle back to 2 during the test. Made me think that the "boost fooler" would make a big difference in numbers by maintaining boost at higher values during the test.

[RT]

How about running some biodiesel? When I run it there is much less smoke and this is at 20% biodiesel. 100% would likely be completely clean. Since biodiesel is legal fuel I don't think they can prohibit you from doing this and that is only if they figure it out. Not very likely. RT