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7.3 very slow when cold

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Old 11-14-2014, 10:25 PM
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7.3 very slow when cold

So my truck has great power when shes all warmed up. But in the morning or when its set for a few hours its very slugish. Its like it need to be reved hard in gear then it slowly builds up power. Now i do use my block heater in the morning and let it warm up. Is it normal for there truck to be slower untell there fully warmed up or is somthin going on
 
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Old 11-14-2014, 10:31 PM
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Is this an idi or power stroke
 
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Old 11-14-2014, 10:48 PM
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im guessing powerstroke, as my idi is faster cold then hot.
 
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Old 11-14-2014, 11:49 PM
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yeah its a turbo powerstroke 1995
 
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Old 11-16-2014, 02:19 PM
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and ill put my foot into it and it just slowly speeds up but then once its warmed up its got great power
 
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Old 11-16-2014, 02:33 PM
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I had a 2002 PowerStroke (I know, it's apples and oranges) that was a total dog cold. It would barely go off idle. I came to the conclusion that the computer didn't think the engine had woken up yet and wouldn't really ask it to do anything until it had figuratively had it's coffee. At least the '02 (but I think the earlier ones like '95 as well) were drive-by-wire accelerators. The driver pushing the accelerator tells the computer that the driver wants more fuel, and the computer takes that under advisement and decides what it wants to do. It was annoying enough (although not nearly as bad as the drive-by-wire in my '08 F-250 gasser) that I won't have another drive-by-wire truck.

If this isn't how the '95 PowerStrokes work, then sorry for the misdirection.
 
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Old 11-16-2014, 02:38 PM
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Something to check...
Do you hear a whooshing of air when it is cold and doesnt run right, then the whooshing is gone and warm and runs good?

If so it is your EBPV(Exhaust Back Pressure Valve) it a basically a choke right on the back of the turbo that closes when cold to speed up the warm up process. Once warm, it opens and allows the air to flow, giving more power
 
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Old 11-16-2014, 05:49 PM
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hmmm the computer thing would make sense, and nope itll start and run just fine and no weird noises. If i put my foot in it and im going through the gear shifting a 2.5k ill get power by like 4th or 5th gear
 
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Old 11-17-2014, 01:54 PM
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its just the computer trying to protect the engine tell it warms up.
 
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Old 11-19-2014, 12:17 PM
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huh really ? yeah that makes sense just wouldnt think my trucks computer would be smart enough to do that cus its the first year of OBOII
 
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Old 11-19-2014, 12:39 PM
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i believe since computers started controlling transmissions/engines they have been like that.

with a manual trans you would have more get up and go cold tho.
 
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Old 11-19-2014, 12:46 PM
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If it is like any of the newer OBDII vehicles (with catalytic converters, so this rule may not apply), it would be quite the opposite. The computer is going to richen the fuel mixture to get the truck to op-temp as soon as possible, because that is when emissions are the best. I have another thought on the matter though. Now if comparing a 95 to an 02 is apples to oranges, this may like comparing an apple to a coconut... But, what you are describing is fairly close to the 6.0 injector "stiction." Basically the hot, high pressure engine oil in the injectors leave behind a varnish that make the injectors not work at peak efficiency when cold. As the engine warms up, the stiction loosens up. I know they are very differently designed injectors, but they use the same basic principles. We have had a lot of customers who have noticed tremendous improvement in their 7.3's cold by cleaning out the injectors with Stiction Eliminator.
 
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Old 11-19-2014, 01:06 PM
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Originally Posted by BoKnowsDiesel
7.3's cold by cleaning out the injectors with Stiction Eliminator.
where can i get that stuff and how much money is it?
 
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Old 11-19-2014, 01:16 PM
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You can order direct at hotshotsecret.com or we sell in most truck stops, Amazon, Tractor Supply stores (TSC), some Autozones, and various independant dealers. MSRP is 61.95
 
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Old 11-19-2014, 04:22 PM
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Originally Posted by BoKnowsDiesel
If it is like any of the newer OBDII vehicles (with catalytic converters, so this rule may not apply), it would be quite the opposite. The computer is going to richen the fuel mixture to get the truck to op-temp as soon as possible, because that is when emissions are the best...
Rich / lean mixture isn't at all the same in a diesel as a gas engine. Gassers need the mixture to be prety close to stoichiometric (perfect mix to burn all the fuel using all the oxygen). So gassers adjust power by throttling the amount of air that goes in and then putting the right amount of fuel in to use all the air. If a gassers computer wanted to limit power it would do it by limiting how far the throttle was opened.

Diesels on the other hand will run with a really lean overall mixture, so they don't throttle the air. Instead they inject the amount of fuel needed to make the desired power. So when the computer wants to limit the power it injects less fuel.
 


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