Okay, brief history... Bought an '86 F250 with a Banks turbo'd 6.9L, approx 154K miles about a month ago... ran fine, but the injector return lines leaked like a sieve. It never quite had the power I was expecting, but I lack a frame of reference, so assumed I was maybe being optimistic about it. I've since rebuilt the return line system, and it no longer leaks. The power is still not there, and I have to hold the pedal pretty far to maintain highway speeds. I'm also getting about 16-ish MPG with my C6 automatic, and 4.10 rear-end... a little less than I was expecting with a turbo...

Fast-forward to yesterday.... the temperature has started dropping pretty rapidly... It's generally 40-ish tops now when I go start my truck. I'm still running #2 diesel, though I've got #1 in my front tank just in case. Yesterday, on my way home from work, I noticed an interesting phenominon...

The truck suddenly seemed to move ALOT better when I was driving it. I know cold is better than warm air for power... but this seemed a little extreme. I also had to hold the pedal a tiny fraction of what I'm used to to maintain cruising speeds... Awesome! Dunno what was broken, but it's fixed now! And 4 minutes later, my speedometer started dropping, and I had to push more and more on the pedal until it was as it was before... and continued to be that way until I got home.

However, when I started it this morning, the same thing happened. I also noticed, that durring this time of better-running, it's got alot more 'clatter' to the sound of it. It sounds more like a garbage truck. And, again, it lasted about 3-4 minutes. Right at that point, I noticed the sound of the engine gradually becomming less 'clattery' and smoothing out, right as my speedometer started dropping, and my pedal had to be pushed farther to keep it at speed. Until at last it doesn't sound much different from a gasser.

So... what the heck is going on? o.o Is air temperature THAT big of a factor? The only thing I can think of that would start heating up within that short of time would be the motor oil... It'd be more viscous, and might seal in more power? But, wouldn't that much blowby be making me burn oil? My exhaust is white when I first start the truck for about... maybe a minute. (My glowplug controller has been replaced by manual button) Then it becomes clear, and I never see smoke again.

I've got no ideas on this one...
Any input is appreciated
Thanks

 

There's a cold start sensor that activates a solenoid that raises the idle and turns up the timing on the injector pump. Once it warms up it drops back down. I'm not sure on the fix though as I am new to these trucks. Might be the timing on your IP or it might be another problem and the turning up of the pump is just a Band-Aid.

 

Sounds like timing, and if I'm understanding right it sounds like you might not be letting your truck warm up enough before taking off. Otherwise if it takes that long to warm up you may be in need of a thermostat. 16 mpg with 4:10's and a C6 is nothing to be disappointed about.

 

Okay, so it is just my timing, kool Just gotta figure out how I wanna go about getting it timed...

As I understand... 16mpg is good with C6 and 4.10's... I was lead to expect about 14-ish.. but shouldn't the turbo improve it by more than 2mpg? The banks site, at least, says 30% better... I'm still happy with 16, don't get me wrong... And eventually I'll stick a zf-5 speed into it... Love manual trannys... If my timing is that far off, will certainly help getting that adjusted properly.

I just put in a new thermostat, when I changed my coolant less than a month ago. I usually start it, and let it run for about 1 minute... I was told that it's good to let them idle for one minute before leaving, and one minute before shutting it off when done...

 

You 'can' drive it after about 1 min of warming up, but I've had mine stall that way more than once when I first got the truck. I let it idle for approx 5 min in the warmer months, and closer to 10 in the colder one's. She operates much better and it gives the trans more time to warm up.

And it sounds like something is up with your timing/IP. My timing is **** right now, but I was on a 3 1/2 week waiting list to get into the only shop where I live with a proper timing meter. So I turned the fuel up a flat to band aid the problem and get me running. Not a long term solution.

 

it sounds like you have a problem similar to what i had for awhile. my cold timing advance solenoid on the IP was recieving power when it shouldn't be, randomly, and when it had power to it, the truck produced a lot more power, such that if i held the smoke pedal at 1/4" from the top, it would accelerate to 80+ mph. for a temporary fix, i unplugged the wire to the solenoid, its the rear one on top of the IP.
working properly, this unit will have power for the first few minutes after a cold start, then remain off for the rest of the drive. in my thread on the subject, i was advised that if the timing is set properly, the solenoid will have little/no effect on performance, but will have a significant effect on "diesel rattle" noise.
when i get around to it, i'll mark exactly where the timing is by putting a mark at the connection of IP to gear housing. then i'll adjust it a little and see how it handles.
i also need to diagnose my wiring to figure out why the cold advance solenoid is recieving power when it shouldn't. i suggest you test it by unplugging it like i did, and further diagnose from there.

 

Time it Diesel pump timing - YouTube

 

that video tells me it would be so simple if i just had the right timing meter, which of course, i don't have

 

I know what you mean i want to buy the same setup

 

i think i'll start by marking where mine is and blindly turning it up a touch, the meter would be nice, but i have more urgent things for the money to go to

 

Coming back to this a bit late... But, I can't seem to get my truck timed around here... So I'll have to do l it myself. Which prompts a question for me...

Since my truck runs so much better when the cold start solenoid is active, I was hoping someone might now how much said solenoid advances the timing? That way I can bump my base timing to it, and should be worlds of better to at least get some clue of where it should be...

Thanks!