Hi guys!

I am needing some advice. I have just acquired a '95 2-door Tahoe. It has 157,000 miles. It has a 3 inch lift and 33 inch tires. It appears to be in very clean shape.

The vehicle seems to have plenty of power and does not smoke on regular driving, but produces gray/black smoke on heavy throttle, like when climbing steep hills. It DOES have a HyperTech chip (I looked), and a '97 K&N under hood filter setup. Otherwise, it is completely stock.

As for the black smoke, the various threads indicate that this is likely due to insufficient boost (too much fuel, not enough oxygen) if it is a stock chip. The HyperTech chip appears to be similar to a 40-50HP chip, as vendors claim that it can be used with stock intake and exhaust as does HyperTech.

My question is: Other than installing gauges to check EGT and boost, what steps should I take to eliminate the black smoke and still maintain reliability and power?

Feel free to 'spend my money'. I am looking to get this truck to an optimum level of performance and reliability, and would be happy to accept any suggestions. I'd like to keep the total bill in the $1K-2K range. What's the best Return-On-Investment for these goals?

Sincerely,

Rob

Just out of curiousity, what is keeping you from putting in a boost/pyro gauge? These could really help diagnose the issue and keep up your reliability up by helping you not to wreck the engine due to heat. If there is indeed a chip, gauges become critical to help prevent a meltdown.

Hi Silvy,

Thanks for the reply. I did not mean to imply that I was not going to put in gauges. I AM. The truck is new to me, and I haven't had a chance to do it yet, that's all. I am probably going to put in a EGT and boost gauge on a pillar mount.

Sincerely,

Rob

get the exhuast opened up beyond stock if it isn't.

Update: Following Walt's advice (http://www.ssdieselsupply.com) that he suspected low boost due to vacuum actuator malfunction, I checked vacuum on the wastegate actuator and vacuum off the pump. Sure enough, we have a bad solenoid. I checked for voltage at the input to the solenoid, and discovered a bad connection. After fixing it, I immediately heard the turbo wastegate actuator engage, and the turbo and engine stumbled slightly and then smoothed out. I took it out for a test drive and WOW - This thing has some serious power now! I can also hear the turbo spooling up during acceleration. It's too dark out to check for smoke, but what I could see in the moonlight looked like it was gone! Certainly the power is WAY up. I will be buying all my upgrades from Walt after this kindness in remote troubleshooting!

I have no idea what kind of 0-60 times you can expect with a 1/2 ton Tahoe, but it seems to me that this is about the highest weight/torque ratio in the 6.5 TD, as the 2-door Tahoe is quite a small/short vehicle. Anyone have any data on this?

BTW, your opinions in spending my money are still valued!

-Rob :)

Like QM said, exhaust for sure to start:ro)

If I had that much to send I'd follow those here before me and get an Intercooler Installed, After Gauges oh course

If you want to haul a$$ w/ no smoke read sig. Bought with 180K miles, just passed 200K. Bone stock when I bought it. Fastest truck I've ever been in.

K&N = :badidea:


I personally think that K&N filters are the work of :devilfing . They have ruined more engines than any single thing on the planet. I wont run one on a vehicle, I wont run one on a lawnmower. I even refuse to have the letters 'K' and 'N' in the license plate of my cars...


Case in point, Brother in law of a fellow at work put one on his '02 gasser when he bought it. Now it uses 1 quart of oil every 250-300 miles, and fouls plugs out as fast as you can change them. The dealer said the rings are shot (at only 35k miles) and they are denying warrantee claims because of the K&N filter.

I say pitch it and go with a delco paper filter.

Tim


ON EDIT: To back up my claim with data, see this link

http://www.dieselplace.com/forum/showthread.php?t=10372&page=10&highlight=air+filter

spend the extra money and get the tranny temp gauge. even if you don't pull a trailer, the larger tires make that tranny hotter. I was surprised to see my tranny temps as high as they are after installing the gauge. Definitely worth keeping an eye on.