Emissions problem for new 6.5 owner

[RCourtney]

New to TDP and diesels - just bought 95 K2500 6.5L TD with 180K. Truck runs and looks great (20mpg?), but it won't pass Wash state emissions (opacity 51%). It hasn't needed inspection for last 4 years due to county of registration. What is recommended: air/gas/oil filters, injectors, pump, better fuel, additives? Probably not much hard mileage but no special upkeep either - just the required/normal - nothing expensive as far as I know. Are brand names important or just individual preferences? If injectors are the answer, do I check them and change some or change them all? Are the injector rebuild/reconditioning services worth investigating? Will biodiesel improve opacity readings? How can I tell if I'm buying good quality fuel? Thanks for any and all help!

[ 03-19-2004, 06:35 AM: Message edited by: Rob Courtney ]

[a5150nut]

Air & fuel filters are critical to diesels. I've got a 94 with about the same miles as yours. I have replaced injectors, glow plugs, & injection pump. The pump I probably could have gone without. Oh and timing gears.

I would start with filters and see how much that helps. Then think about injectors. And then if still not clean enough, timing set, gear or chain.

Have you checked for any codes set in the computer?

[tom.mcinerney]

Advice above good. If low/no turbo boost, will run too rich. EGR and CDR might effect. The injectors might need renewal, if original--spray deteriorates, less atomised. The catalytic converter could be a little clogged. I think an hour or so at highway speed might help before testing. Sometimes the mufflers load up with carbon, a good run blows them out too. DO check codes.
Filters, injectors, injection- and valve-timing all relevant; fresh oil may seal better.

[Craig M]

After the fresh filter suggested by others, might try some of the diesel fuel additives. Most parts stores have various additives to help power. A large does might help injectors and get it clean enought to pass the opacity test. Not sure if vegitable oil will help. Will call friend and ask him.

[RCourtney]

Thanks all - air filter looks new, will check gas filter and codes tomorrow, but shouldn't I get a "Service Engine Soon" light if codes are being thrown? I'm trying some "Redline" fuel additive, cetane boost and stabilizer - hope it's good! I'm having trouble believing that there's anything major wrong as engine seems to run smooth and strong. I did notice a pile of soot under the tailpipe after I moved the truck today - is this to be expected? Also, I don't notice any smoke when it's running...

[charliepeterson]

Sometimes you can't see the smoke unless you look in the head lights of the cars behind you. Try really winding up the rpm's on a stall test and let it go. If you don't have a boost guage then look through the back window for the smoke trail.

[mbrew]

I went through the Washington DEQ in Vancouver last Fall. I failed miserably the first time. I went home and reinstalled my stock chip and went back for another test. I failed though not as badly. I went back home and changed my oil and filters. Then I observed the smoke when I did the snap test. I discovered if I eased into it, the fuel and the boost were matched and smoke was nearly non-existant. If I just mashed the pedal hard and fast, the smoke was obvious. With your diesel, they should let you stay in the truck and operate the throttle. On my third trip to DEQ, she passed with flying colors and very little visible smoke. I believe I could have passed the first time if I had "studied" for the test. Good Luck.

[number two]

Maybe a nice tankful of thinner Kerosene before the test might do the trick-less BTU's=less smoke?

[DmaxMaverick]

The use of kerosene would likely exaggerate any condition causing the smoke. Less BTU's would mean more by-products (soot) in the exhaust for the same fuel input. The best bet, chemically, would be to add a healthy dose of cetane boost, say, +8 or better. It will smooth out the engine and help to burn the fuel as completely as possible. Even removal of the air cleaner element during the test period would not be detrimental.

Another option (or in addition to everything else) would be to "limit" the pedal travel with a block, or something similar, either under the hood or along the linkage somewhere. About 3/4 throttle would be enough to give sufficient power to drive around unloaded, and give the illusion of "hammered down" when you get to the shop.

It may also be necessary to "re-plumb" the crankcase vent if you have excessive blow by. The "sniffer" has no way of knowing what "fuel" is causing the opacity, whether #2 or engine oil.

Good luck

[RCourtney]

Could anyone explain what Charlie means by a "stall test"?

[charliepeterson]

I'm sorry. "stall test" Push the accelerator to the floor with the truck in gear and your other foot on the brake pedal to the floor as well.
You may hold this position for only a short time because the torque converter in the transmission heats up. If you notice the rpm guage during the test it may shed light on how healthy everything is.
I haven't done this in a while so memory is suspect here, 1900-2050 rpm's is a good transmission? If these numbers can't be reached than the engine power is suspect. If these numbers are greatly succeeded then the transmission is slipping.If the tires start to break free now, the engine is putting out enough power and thr transmission is good.
This test on a known good truck is a great starting point for diagnosing trouble in the future. It's good for diagnosing transmission or engine issues.

[patrick m.]

i would agree with "mbrew", instead of hammering the throttle, "roll" into the throttle nice and easy.

[charliepeterson]

I know for a fact we can't "roll into it" when doing the Opacity test in Mass. Unfortuneately we must go to the floor boards and hold it for a long three or four seconds. The test does give it a chance to pass, it really has to "smoke" to fail.

A new air and fuel filter along with an extra dose of cetain conditioner and a good run to help clean out the injectors might help. Maybe an extra "saw buck" to the inspector to kick the sample hose off the truck might help too.

[a5150nut]

If you have to hammer it to the floor, what happens when you get to 2400rpm and the boost drops off? Don't give a guy much chance does it?

[JohnC]

Once it hits the rev limiter the fuel pulls WAY back. It's only that brief moment between hammer down and redline where it's getting full fuel. No turbo's ever going to be able to keep up with that.