new engine and tranny
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Logistics Pro
Joined: Oct 2008
Posts: 4,818
Likes: 1
From: Avilla, IN
new engine and tranny
I was looking in Autotrader and there was a reg cab 2001 F-350 srw v10 with 170,000 miles on it. Ok seems good, but then the ad said that the engine and transmission had been replaced 25,000 miles ago. To me that seems odd, because I know a member on here that beats the living crap out of his and hasn't had any reason to do this. What do you guys think could have happened to need the engine and transmission replaced?
Posting Guru
Joined: Aug 2008
Posts: 1,845
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From: No.Va.
Could be any number of things. (s**t happens)
Some people neglect their vehicles and they run forever.
Some maintain per manual,and still have troubles.
The seller couldn't answer that question?
I would verify that the replacements were done before buying it.
Some people neglect their vehicles and they run forever.
Some maintain per manual,and still have troubles.
The seller couldn't answer that question?
I would verify that the replacements were done before buying it.
Postmaster
Joined: Oct 2008
Posts: 3,924
Likes: 6
From: Richmond BC
my truck has a NEW engine but the tranny was simply rebuild while teh engine swap occured..
apparently the previous owner melted a piston so bad a rebuild was impossible...what i was never able to figure out was if its was a longblock or short block install...
truck currently has just under 200K miles, engine blowed up around 180K mark i beleive...
so it can happen...
apparently the previous owner melted a piston so bad a rebuild was impossible...what i was never able to figure out was if its was a longblock or short block install...
truck currently has just under 200K miles, engine blowed up around 180K mark i beleive...
so it can happen...
Thread Starter
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Logistics Pro
Joined: Oct 2008
Posts: 4,818
Likes: 1
From: Avilla, IN
I didn't call the owner I was just curious how both could happen at once. How do you melt a piston in these V10's anyway? I don't know that much about them, what are your EGT's like?
Postmaster
Joined: Oct 2008
Posts: 3,924
Likes: 6
From: Richmond BC
truck dont have a EGT meter..
but the engine never runs HOT.. always in the middle of the guage..
i have no idea what the previous owner did that caused the issue, but in the past the trucks entire life was pulling a 5TH wheel TT..
but the engine never runs HOT.. always in the middle of the guage..
i have no idea what the previous owner did that caused the issue, but in the past the trucks entire life was pulling a 5TH wheel TT..
Postmaster
Joined: Oct 2006
Posts: 4,171
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From: SE Texas
On 6.8L's, the OEM PCM programming NEVER allows the engine to enter "power enrichment". The engine runs at stoich air fuel mixture off of feedback from the O2 sensors unless the PCM's temperature models determine that the catalyst, exhaust manifold(flange), or O2 sensor temps are exceeding a safe limitation. If this happens, the PCM commands an excessively rich (approx 10:1) fuel mixture to cool them off. Here's the problem with that strategy....Fuel has it's highest energy content and also it's highest heat content when it's at the stoich point of air/fuel mixture. Spark knock causes HUGE swings in temperature and cylinder pressure, and the OEM programming makes the 6.8L a knock prone engine under load. The reaction time of the PCM can be a bit slow to react to large temperature spikes in the combustion chamber(especially when towing a heavy load like a 5th wheel TT). Unfortunately, sometimes it's too late for the pistons-they take a beating and sometimes fail before the PCM can react and cool things off. That's one of the reasons I HIGHLY suggest the first modification to ALL 6.8L trucks is a flash tuner from a knowledgeable tuning company.
JL
JL
Postmaster
Joined: Oct 2008
Posts: 3,924
Likes: 6
From: Richmond BC
thats dam good info Johnny...
i myself wasnt aware that the aftermarket tuners could deliver fuel maps "faster" then the stock PCM..
or is it just the entire fuel map is thought throu smarter so it never puts the truck into this sistuation of wild temp swings ?
i myself wasnt aware that the aftermarket tuners could deliver fuel maps "faster" then the stock PCM..
or is it just the entire fuel map is thought throu smarter so it never puts the truck into this sistuation of wild temp swings ?
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Postmaster
Joined: Jun 2008
Posts: 2,564
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From: Wayyy NoCal, USA
Both!
The computer always works at the same processing speed, but the algorithm used for adjusting fuel trim varies.
Program 1 may say to take 30 readings, average them, and then adjust by no more than 1%.
Program 2 may say take only 10 readings, and then allow adjustments by as much as 3%
You can see that 1 would lead to a slower reaction to an extreme situation than would 2.
And most tuners put the system into "open loop" enriched mixtures much sooner. Some as soon as 75% throttle. Not so good for fuel economy, but good to avoid excess temps.
The computer always works at the same processing speed, but the algorithm used for adjusting fuel trim varies.
Program 1 may say to take 30 readings, average them, and then adjust by no more than 1%.
Program 2 may say take only 10 readings, and then allow adjustments by as much as 3%
You can see that 1 would lead to a slower reaction to an extreme situation than would 2.
And most tuners put the system into "open loop" enriched mixtures much sooner. Some as soon as 75% throttle. Not so good for fuel economy, but good to avoid excess temps.
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Postmaster
Joined: Oct 2006
Posts: 4,171
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From: SE Texas
There's a parameter in the software labeled "Time_to_delay_open_loop"
This is the time delay when the PCM should command open loop fuel enrichment. In the OEM tune, it's a 60 second delay. This timer starts when ALL other requirements for open loop enrichment are met. Basically-this is another item that prevents open loop enrichment. In my file,this value is set to 0.
Another parameter that affects the time that it takes for the fuel enrichment to occur is "fuel_open_loop_tp". In the stock file this value is 624 TP counts(nearly WOT). In my file this is 500 TP counts. You don't want open loop too easy-that would kill fuel economy,but you do want it to go into open loop enrichment when needed.
JL
Former Vendor
Joined: Sep 2000
Posts: 2,627
Likes: 76
From: South Carolina
There are several things that need changed to get the tune safe.
There's a parameter in the software labeled "Time_to_delay_open_loop"
This is the time delay when the PCM should command open loop fuel enrichment. In the OEM tune, it's a 60 second delay. This timer starts when ALL other requirements for open loop enrichment are met. Basically-this is another item that prevents open loop enrichment. In my file,this value is set to 0.
Another parameter that affects the time that it takes for the fuel enrichment to occur is "fuel_open_loop_tp". In the stock file this value is 624 TP counts(nearly WOT). In my file this is 500 TP counts. You don't want open loop too easy-that would kill fuel economy,but you do want it to go into open loop enrichment when needed.
JL
There's a parameter in the software labeled "Time_to_delay_open_loop"
This is the time delay when the PCM should command open loop fuel enrichment. In the OEM tune, it's a 60 second delay. This timer starts when ALL other requirements for open loop enrichment are met. Basically-this is another item that prevents open loop enrichment. In my file,this value is set to 0.
Another parameter that affects the time that it takes for the fuel enrichment to occur is "fuel_open_loop_tp". In the stock file this value is 624 TP counts(nearly WOT). In my file this is 500 TP counts. You don't want open loop too easy-that would kill fuel economy,but you do want it to go into open loop enrichment when needed.
JL