my 6.9 is very sluggish

[turkeyslayer0]

I have a 6.9 non turbo that very slow about accelerating, even when in park, idles fine with just a little white smoke any suggestions? thanks

 

[franklin2]

Disconnect the throttle cable under the hood and see if it's opening the throttle all the way. Usual suspects are floor mats and carpets.

 

[turkeyslayer0]

thanks will try that today

 

[chris142]

Mine runs much better on a cool day vs a hot afternoon. My timing is set, my fuel turned up a little and I have a free flowing exhaust. It's still embarrassing slow to accelerate.

Just yesterday I watched an old Geezer in a step side GMC with a 250 inline 6 and a 3 on the tree walk away from me leaving a light.

 

[chris142]

I have never driven one with a turbo

 

[chris142]

I couldn't imagine how slow it is without a turbo. Mine was miserable but got new pump and injectors and it's not fast but I'd go so far as to call it quick. That's with a turbo though. Maybe you are expecting too much from it? Set timing and if it's still slow and not smoking it may be time to go through the fuel system?

And you can forget about accelerating up hill lol

 

[MTKirk]

With a new injection pump and injectors, my NA 6.9 is pretty dang quick (timed to 8.5 btdc). Faster than I can shift my T-19 anyway. It has more snap than my 1985 GMC 3500 had (small block V8).

 

[Agnem]

I have a 6.9 non turbo that very slow about accelerating, even when in park, idles fine with just a little white smoke any suggestions? thanks

Did ANYBODY read his post? He said "Even in park." Sounds like your IP is gummed up. Have you been running funny fuels? How many miles are on the IP and injectors? If around 100K, it's time for a refresh.

 

[Knuckledragger]

Mel is right if the mileage is high, but it sounds like it could be out of time, too. The white smoke tells me blowby, which says high mileage/heavy use. Check timing first. If that does not help, time to rebuild the engine and change out for a new/rebuilt IP. My 6.9 NA w/c6 squeals the tires from a start if I want and has never been timed.

Do a compression check, too. I also have a 6.9 turbo engine that will not fire because of low compression.