1994.5 - 1997 7.3L Power Stroke Diesel  

Low HPOP pressure?????

  #1  
Old 08-18-2008, 04:20 PM
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Low HPOP pressure?????

So I was towing home a deuce and a 1/2 frm kentucky. I am wondering if my HPOP is going further south than the truck. If I put a 12.6 resistor in for the 10 k mod, the motor sounds like its predetonating. I dont understand. carrying all that weight, and at 60 mph, WITHOUT kicking it down to drive I am hitting about 8 pounds boost. I thought it should make more. My 96 and the 97 I had made more, but It could be attributed to the gauge difference. Its throwing me for a loop that I dont get. I am not making a HUGe amount of smoke, but you can see a little black haze behind me.

So, is there a way to find out the HPOP pressure? Perhaps I am not getting enough fuel.

Maybe I have a leaking up pipe, I will have to check all hoses.

How much will a ntercooler drop the EGTS towing something of decent gerth???

These questions need answers guys, solid hard answedrs, no guesses.....LOL
 
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Old 08-19-2008, 09:39 AM
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I'd say you're only hitting 8 lbs of boost because you're in OD at 60mph. You're not spinning enough RPM to build much. You need two things to build boost, fuel, and RPM. You're lugging it, so you have lots of fuel and little air to burn it, and that's what drives EGT through the roof. Kick it down out of OD, let it spin up to 2K+ RPM and see how it does. When I'm loaded I like to hit the bottom of hills doing around 2400 RPM, that seems to be my sweet spot for good compromise between boost, egt, and reasonable rpm on my rig.
 
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Old 08-19-2008, 02:00 PM
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Boost pressures sound normal for those conditions loaded. HPOP issues are unlikely unless it set a CEL. I would check fuel pressure under load for the "predetonation" noise if that is what you are hearing. You could have low FP.
 
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Old 08-19-2008, 02:06 PM
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I would try cleaning the FPR screen as well. That has been a fix all for me kinda like the CPS.
 
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Old 08-19-2008, 05:55 PM
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I know what builds the boost, but thought it was a tad low. I think the gague might have a little leak on the hose into the back of it after looking today.

mag Karl, coon, tj, or anyone else who has a intercooler on their trucks, how much of a decrease did you see EGT wise after the install? I am trying to get a ball park figure so I know if it s worth the headache in trying to find one around here. Please advise. Thanks for your time.
 
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Old 08-19-2008, 08:11 PM
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I saw about 150-200 degree. its pretty hard to gauge. could have been more
 
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Old 08-19-2008, 08:15 PM
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yeah i'd say i saw about 300 average (post turbo though so probably around 350 pre-turbo) when i installed my intercooler.. but that's also cause the stage 2s used to run slightly warm before that.... and also 8 lbs lugging it at 60mph doesn't sound that far off at all.... with stock sticks and just some small mods.... kick it out of OD and it'll probably be around 18-20 under kinda heavy throttle
 
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Old 08-19-2008, 09:50 PM
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150 to 300 sounds to me like its worth it. Only problem that I can forsee is the map sensor being so far from the pressure zone. Has anyone had problems with this or am I overthinking it?? Seams to me like it would have to be moved in order to keep from setting a cell....... Was just a thought.......
 
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Old 08-19-2008, 10:00 PM
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Originally Posted by Todd525
150 to 300 sounds to me like its worth it. Only problem that I can forsee is the map sensor being so far from the pressure zone. Has anyone had problems with this or am I overthinking it?? Seams to me like it would have to be moved in order to keep from setting a cell....... Was just a thought.......
nope no issues... some guys move the line right after the turbo, before the intercooler, and claim that they get a "bigger puff" when they gun it... but i doubt it's enough of a difference to force me to change where mine is
 
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Old 08-20-2008, 09:47 AM
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I still think you need to shift down and avoid lugging it if you want more boost and lower EGT. I haven't heard of many guys that needed an IC running a stock rig, though I don't see how it could hurt. Before I got my chip, I had intake, DP, exhaust, and guages. I could still hit 1200 pulling my trailer, but it was rare. If you do add an IC, I would block the passenger head plenum MAP port and extend your MAP line over to the compressor outlet. Many here have reported much reduced lag by doing it that way. I did mine that way and notice no difference in lag before and after the IC install.
 
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Old 08-20-2008, 10:02 AM
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around here, we have some long hills, a mile or so, and I haul 15k to 19k pretty regular basis. That is not combined, thats the load, so 1200 can be reached even pulling my 15k pound 5th wheel camper.
 


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