1986 6.9L idles perfect, no smoke just going around town, cranks perfect unless when a little colder but just takes a second try and starts right up.

I just bought it in Colorado Springs and I’m driving it back to Florida. Had a problem with once getting up to around 45-50 mph if I accelerate it starts smoking bad and kinda popping/cracking out the pipes ( has dual glass packs).

It doesn’t do it all the time though. It seems like it only would do it when it got colder like below 40. It’s not black smoke either not really sure if it is blue or whit this is my first diesel. I have been keeping the tanks topped off at every gas station that has diesel so maybe I’ve just been getting some crap gas? No loss in acceleration just smoking bad and kinda chugging/cracking.

 

Try changing the fuel filter. Might want read about it or get someone to show you . A little tricky if you have not done it before though.

 

Might be bad fuel filter (as norm stated), but also make sure your lift pump still has power. When my e-pump was weak, it would run fine in the city and idle, but at highway speeds, it would lose a lot of power.

Also, you might have air intrusion or fuel line restrictions that is starving the IP for fuel at higher loads. This would coincide with colder temps, cuz the fuel is thicker and harder to flow thru the fuel lines. You might want to run a bunch of Diesel Service or diesel-rated isoheat to help with the flow.

 

Thanks I put PS diesel service in it while out there and it did seem to help I think. But I’m now back to Florida. It seemed like it would only do it when I started to get back into the mountains. Once I was out of New Mexico it ran perfect was driving 7-10hrs a day at 55-65 mph and never had a hiccup.

I got back Wednesday night real late and it sat until I started it this morning. Started right no problem but then when I put it in reverse it kinda got real low but didn’t think anything of it, backed out of my driveway then put in drive and went to take off and it stalled. It started right back up I drove it down the road and gassed it and right when I let off it stalled again but started right back up again.

I drove it back and took my car to work instead so I haven’t had a chance to look at it, but could that be weak batteries I know they are older maybe 2011 and before I bought it he had them charging so could they have just drained down from not being driven in 2 days?

 

The original issue sounds like retarded timing; as ip and injectors wear, the timing gets slowly retarded. More throttle retards the timing.

The second issue is air in your fuel. Check the fuel line loop next to the lift pump, and the lift pump first.

Batteries won't cause any issue aside from not starting - once the engine is going(provided your alternator is working), you don't need /any/ batteries. And, even so, it takes only 6V to keep the fuel shut off solenoid "on", at which point no lights or anything would be working, it wouldn't crank etc.
So stalling is *not* that. It's a lack of fuel.

 

sorry wrong thread