Black smoke Issues

[FLSTSS]

First off thanks for taking the time to read my post. I have a few thing maybe I could get some input on. Ok when it comes to gassers I'm pretty good, I built and still have a 70 El camino 350 stroked to 383 671 supercharger 2 650 dps and 250hp of juice (NOS) w/6speed Richmond trans. As for the turbo diesels I'm pretty much clueless so be gentle. any way back to my questions.
1st the black smoke. I got this 1997 K1500 4WD Z71 extra cab in Feb. of 04' with 100020 miles on it, if the 1 was not on the odometer I would have thought it had 20 miles on it. super clean truck. I'm the 2nd owner. I only did a few things to this truck, 4" exhaust from the cat back, a less bent turbo down tube. and a boost and a preturbo ET gauge. the truck now has about 125000 miles and 2 or 3 months ago I noticed more than the usual black smoke in the mirror when I give it some throttle to pass or go up a hill, I thought maybe I never really noticed it before, but now I'm always looking in the mirror on start up it will puff some bk smoke, after I drive it and I sitting at a light or something I see some coming out of the pipe, I accelerate slowly and it gets a little thicker, then I no longer see it. it seems to come and go, maybe I'm just can't see it all the time. But when I step on it a bit it really starts to come out. So black is too much fuel Right. I did check the vac @ the turbo ( I guess waste gate) vacuum valve it was 15psi and I was able to move the piston freely with the engine off. Some more info on a flat road it will do 60mph with 1 to 2 psi boost and between 500-600 EGT, I did notice a few times when I would look up at the boost gauge thinking it would be in boost the needle was flat, I press down on the peddle a bit more and the needle shot up the 4 psi, I don't think that is right. I did put water injection on and I had to tap the inlet tube for the nozzle the tube between the turbo and the engine. when I took it off to tap it, the area when it bolts to the manifold under the EGR valve had a lot of soot in there I did loosen it up and sucked it out w/ the shop vac. also the rear 1/4 panel gets covered in soot. Ok what do you think?
2nd after market air intake filters. what's your take on this issue?
3rd the Cat do I need it? I see it as something else to get clogged by soot. if I can take it out any computer problem come with it?

Thanks sooo much for taking the time to read about my problems.

[tcrawfo]

Scott, I'm having similar issues with my '95 Suburban and have gotten some advice in my post titled, Tons of Black Smoke. You might want to take a look at that discussion for some ideas.

Good luck!

[moondoggie]

Good Day!

I don't really know much about these things, but not many responses, so here goes

[twaddle]

Hi Scott,
I'd check that EGR valve in the intake plenum is seating ok.
It may be intermittantly sticking open which can and usually causes black smoke.

Just in case, have you checked the air filter?
Might be worth while installing a new one, it may make the difference.

Good luck.

Jim Twaddle
Biggar, Scotland.

[G. Gearloose]

I suggest getting a turbo-master from heath and don't look back, literally..

[BobND]

Originally posted by twaddle:
Hi Scott,
I'd check that EGR valve in the intake plenum is seating ok.
It may be intermittantly sticking open which can and usually causes black smoke.
Jim Twaddle
Biggar, Scotland. If you are not subject to emissions inspection, simply plug the vacuum line going to the EGR. Leave it tee'd over to the baro sensor, so the computer thinks it's still operating the egr. (at least on the older units '94, etc, this works, I don't know at what point the computer may have been made "smart" enough to know you've done this.)

[Hubert]

I am no expert but here are some points to consider.

Loosing the Cat will improve turbo spool up and reduce smoke some. When I did mine I was surprised how dirty and plugged it was. You could punch out CAT if emissions inspectors want to see it. (Personally I feel after 70,000 - 100,000 miles on the cat it does more harm than good.)

Assuming you have good turbo and boost and its not tons of black smoke but not as clean as when you remember....

No. 1 - Injectors: Someone posted a while back having problems passing an emissions opacity test (~visable emissions or "smoke")and had a 36% improvement in emissions testing with new injectors and timing reset. Many say injectors are good for about 100,000 miles. They don't neccesarily just die but deteriorate. Nozzle performance (fuel atomization), crisp and accurate opening/closing and injection pressure are key to better combustion and less smoke. (Newer generation engines are higher pressure and will increase more in the future).

Fuel filter maintenance is important for keeping IP and injectors clean. Fuel quality is really big. Many run additives to clean and lubricate the IP and injectors and to improve combustion. Some additives have increased smoke for me - some improve it. Could use every tank or periodically as maintenance.

Clean air filter is important and good motor oil both changed or cleaned often also influence smoke. Aftermarket gauze type air filters are really touted by some. Just so its clean and not restricting the intake of air.

[ 08-30-2005, 01:03 PM: Message edited by: Hubert ]

[FLSTSS]

Thanks all for all your input. I'll be busy this weekend spining wrenches.....