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Old 05-28-2012, 12:14 PM

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Powerloss and MPG

Recently I have seemed to have developed a loss of power towing and my fuel mileage has decreased. While the truck seems to run smooth, no smoke of any color, and when not towing seems okay.

I have a auto meter boost and egt gauges, I don't seem to be making the boost I once was. I don't drive the truck often, maybe once a week or two weeks. Mostly used to tow my trailer and early bronco or to haul something. Problem seemed to really develop over a two day trip.

I first noticed a loss of boost psi in my gauge. 20 psi wasn't uncommon if I was into it hard. But now it seems 10 is a struggle and 5 is typically the max. Granted it could be the gauge itself. But I do feel a loss of power so I doubt it.

I have gone over it and found no leaks where I could be loosing boost, checked the impeller and looks good along with play in the impeller. I have about 500 miles since my last change with rotella. New fuel filter and air filter and cleaned the fuel manifold screen. I have a mbrp downpipe and straight pipe 4". New mechanical fuel pump, new cam sensor. Last year it got a new ebv pressure sensor and the tube thoroughly cleaned, Fuel Injection Control Pressure Sensor.

I pass the contribution test, and the buzz test keeps flagging a p1298 idm fault. But everything I have read states I should have a no start condition with this code, I don't it start fine.

Some quick numbers I grabbed with the scanner
ebv psi seems to read about 15 psi about 50 mph
ICP voltage about 1 cruising and 3.0 WOT
Inj control pressure approx 2500 at wot
Map at idle 14 psi and approx 22 wot

I tried unplugging the map and made no difference. I also have wired the ebv valve open and made no change.

Fuel pressure
@ idle 70 psi with a 3 psi swing or pulse in the needle. With key off drops to 50 psi and gradually loses pressure very slowly. At WOT seemed to center around 50 psi with a violent pulse in the needle. This was before I replaced the mech pump.

When towing I typically see 14-16 mpg and I am now getting 9-10 at best.
I also seem to be running higher egts then normal. Seems when towing it pretty much stays at 1200 while attempting to maintain any highway speed. It doesn't seem to push past 1300 no matter how hard I push it.

I think some of the power loss is the stock Torque converter at 256K miles. My trans shifts fine, but I am pretty sure the converter is tired and robbing some power. But I wouldn't think I would lose boost over it.

I don't have access to a scanner today. I can't say for sure as I don't drive the truck often and rarely ever through the winter, but if I had to say I think the idle is ever so slightly rougher. I honestly cant tell but it just 'feels" off from what I thought it had been and almost to me sounds just a hair different at idle as well. I can't say for sure but its just this slight observation. It might not be at all different then its ever been but just a feeling
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Old 05-29-2012, 06:07 PM

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It seemed worse cold and better at operating temp.

I have the trans out now as I am replacing the known clapped out converter since I bought the truck. While out I am replacing the gaskets at the manifold y pipes to turbo as there is traces of black around the gaskets. Unfortantly 3 of 4 bolts holding the pipes to turbo broke :fish: and had to cut the 4 bolts at the manifold. What a nightmare. Gonna look into deleting the ebv from the turbo while I am at work tomorrow as well.

I didn't see any large leaks or obvious other then the small amount of black off the y pipes. But the back of the pass head seemed to have alot of soot on it.
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Old 06-03-2012, 09:27 AM

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I haven't had a chance to check my mpg from yesterday, but everything is better in the powerstroke world.

I replaced my torque converter with a "RV" style from d&e. While there replaced the leaking up pipe gaskets at the collector. These had been leaking since I purchased the truck, not bad, but could see the traces of black around them. Which led to removing the turbo after the up pipe to collector bolts broke. While having the turbo off I gutted the ebpv actuator as it was leaking oil, as well as removed the butterfly and rod. Replaced the pedastal orings.

Now to admit stupidty....

While I was under the hood messing with the turbo I pulled the boost line out of the grommet where it attached via the map sensor hose. When I went to reinstall the small line into the grommet I found the backside of the grommet (out of sight) had been ripped line to line. Which I assume was giving me my low boost readings at the gauge as well loosing boost for the motor.

So now with all this done, I seen 22-23 psi of boost. A def increase in power from cruising to accel up hills, appears a drop of 50-100 rpms at cruise speed. SLightly lower egts. As well I have always had a "double bump" feel to the 2-3 or 3-4 shift (can't recall). Felt as if it shifted and then instantly locked up the converter giving it a second shift feel. It no longer does that. Shifts good and smooth at all points now.
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Old 06-04-2012, 08:39 PM
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Good stuff. Glad to hear!
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