fast=smokier

[tukr]

On a slight incline, why does my 6.5 td smoke a lot at 70 mph, but not at 65 mph?

[tukr]

Wow...really? Nothing? Thanks

[DmaxMaverick]

Welcome aboard!

No surprise, really. You posted a very vague question, with almost no detail or vehicle information (fill in your signature), and probably in the wrong forum. This is the "6.2L" forum, meaning, unless your 6.5L is N/A (no turbo), it should be in the 6.5TD forum. If that is correct, don't start another thread. I'll move this one. No worries, we'll get it straightened out.

What year and model truck? Mileage? Service history?
Miles since last fuel/air filter replacements?
Aftermarket modifications?
Additional instrumentation? (does it have boost/EGT gages?)
Load?
What does "smoke a lot" mean? Billowing clouds? Hazy stream? Occasional puff?
What color smoke (very important)?
Altitude and temperature?
Is there a time or condition when it doesn't smoke under the same load/speed?
Other issues "not worth mentioning"?

[tukr]

ohhhhhhh....i see.
As my ID says, I'm in Waco. Altitude unknown.
Black smoke and its a 6.5 TD (turbo diesel)
year 1999, 1 ton dually 4x4 crew cab with a boost gauge
Again....assumed same load etc but as stated smokes (black smoke ) at 70 up a slight grade but not at 65 up a Similar grade.
Just recently installed a new boost sensor but the 6.5 td was doing this before that. runs great

[DmaxMaverick]

Is there any difference in boost pressure between 65 and 70? What is the boost pressure? Any noticeable loss of power?

Check/replace the air filter. Check the filter plumbing for obstruction or collapse.
Check vacuum pump and wastegate solenoid operation. At idle, you should have a steady 22" Hg minimum at the pump outlet (25" ideal), and modulated 15" Hg at the wastegate actuator. If either is less, look for damaged lines and leaks. If the vacuum pump is weak or fluctuates, replacement is necessary.

[tukr]

no boost....or 3-5 lb at most in either situation. 10 lb under heavy accel. but that wasn't the case nor necessary in this situation.

[tukr]

no difference in power in either case...just lots of blk. smoke under Light accel. at 70mph versus same accel. at 65mph with a light whiff if any smoke.
Also....whats with this stupid "secret code" thingy to ask or reply with Every posting?

[DmaxMaverick]

Just to be clear.... No boost, or it might be 3-5 PSI, at 65-70 MPH, under the same conditions?

Back to the vacuum and wastegate systems checks.

[DmaxMaverick]

....whats with this stupid "secret code" thingy to ask or reply with Every posting?

Normally, it'll pass once you've been active here for a little while. I'll bypass the wait, since it appears you may not be a bot.

[tukr]

yup....same conditions

[Robyn]

Hi

If you are seeing 3-5 psi at road speed and still seeing heavy smoke, then there are likely other issues.

Air filter, clean or new ????

How many miles on the engine ??

Have the injectors been replaced anytime recently ???

Black smoke is due to too much fuel and not enough air to complete combustion.

With the year of the rig, huge clouds of black smoke certainly might set an SES light (code)


Another possibility could be a plugged Catalytic converter (soot trap)

This year of rig has a computer controlled fuel system and unless something is amiss the exhaust should be clean


Another possibility is that a CRITTER has moved into the air snorkel in the RH fender and set up house keeping, plugging off the air flow.

I have seen a rat make a home in these places and cause all sorts of troubles. :(


A failed vacuum control on the waste gate system should set a code.

Be sure the vacuum pump is supplying a steady 26" hg at the pump.
If the needle on the test gauge flutters the pump is junk.

You should see about 20"hg at he waste gate actuator with the engine running.

If there is marginal vacuum and the pump is good then suspect the waste gate solenoid (LH VALVE COVER MOUNTED) and or the plastic/rubber lines

Good luck

Keep us posted

Robyn