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strange piston failure?

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Old 08-28-2017, 06:57 PM
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I can post plug pictured soon as I'm almost back to the truck. so why do you guys think my afr seems to be rich but I'm lean failing? maybe I should rig up a pressure gauge and drive it with the new engine to see what it does when I'm in it. I'm still running stock rails and reg with a single walbro450
Old 08-28-2017, 07:15 PM
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Originally Posted by Dylanplace
I can post plug pictured soon as I'm almost back to the truck. so why do you guys think my afr seems to be rich but I'm lean failing? maybe I should rig up a pressure gauge and drive it with the new engine to see what it does when I'm in it. I'm still running stock rails and reg with a single walbro450
We think it's lean failing because your pistons show it.
Without a boost referenced regulator for every pound of boost you're losing a pound of fuel pressure, So you may have a base pressure of 58lbs but at 15lbs of boost the injector is only able to flow 43lbs.
Old 08-28-2017, 07:20 PM
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Originally Posted by LLLosingit
We think it's lean failing because your pistons show it.
Without a boost referenced regulator for every pound of boost you're losing a pound of fuel pressure, So you may have a base pressure of 58lbs but at 15lbs of boost the injector is only able to flow 43lbs.
that makes perfect since to me. so I can see the benefit of running one for sure when you out it like that but arnt their all kinds of people running stock rails and fpr and making power?
Old 08-28-2017, 07:26 PM
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would adding a second pump help combat that issue at all. I guess I'm going to have to get rails and a reg but would still like to play around with it some more. it's all good learning to me
Old 08-28-2017, 07:55 PM
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Originally Posted by Dylanplace
that makes perfect since to me. so I can see the benefit of running one for sure when you out it like that but arnt their all kinds of people running stock rails and fpr and making power?
Most are but they run a second pump that comes on with boost or with a "Boost a pump", A referenced regulator adds pressure at 1 to 1 so at any given boost pressure it adds only what is needed. 8lbs boost adds 8lbs pressure and so on.
Old 08-28-2017, 08:48 PM
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Old 08-28-2017, 08:49 PM
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I typically run br7ef but someone told me to try the copper champions so they were brand new. but as you can tell from the pistons she got Smokey
Old 08-28-2017, 09:12 PM
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Won't the stock regulator add fuel pressure with boost as they get has vaccum reference?
Old 08-28-2017, 09:16 PM
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Originally Posted by rotary1307cc
And how much timing
+1

How much timing and has the timing been verified accurate and corrected
Old 08-28-2017, 09:18 PM
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Originally Posted by LLLosingit
We think it's lean failing because your pistons show it.
Without a boost referenced regulator for every pound of boost you're losing a pound of fuel pressure, So you may have a base pressure of 58lbs but at 15lbs of boost the injector is only able to flow 43lbs.
That is fine as long as his injectors have duty cycle left. IDC can make up the volume by being open longer. Now if he checks his pressure at the rail during a run and it's tanking that is a recipe for disaster.
Old 08-28-2017, 09:42 PM
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Originally Posted by SethU
+1

How much timing and has the timing been verified accurate and corrected
my actual timing according to hp and my gauge reader is sloped from 20 degrees at 0psi dropping to 15 degrees at 15psi
Old 08-28-2017, 09:47 PM
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Originally Posted by sbcgenII
That is fine as long as his injectors have duty cycle left. IDC can make up the volume by being open longer. Now if he checks his pressure at the rail during a run and it's tanking that is a recipe for disaster.
I'm running id850 injectors. only using about 40% I can check some logs though
Old 08-29-2017, 05:11 AM
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Originally Posted by Dylanplace
I can post plug pictured soon as I'm almost back to the truck. so why do you guys think my afr seems to be rich but I'm lean failing? maybe I should rig up a pressure gauge and drive it with the new engine to see what it does when I'm in it. I'm still running stock rails and reg with a single walbro450
because it isnt "lean failing" as you call it, and as has been said already you're detonating the **** out of it...which your plugs also clearly show by the fact they're all destroyed too !
Old 08-29-2017, 06:40 AM
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having a boost reference or not means exactly jack....if the car is tuned for it. SBCGENII hit it, if the VE or MAF curve is tuned to handle the drop in fuel pressure as boost rises, then its fine. I would have thought there would have been more marks on the piston face if it detonated itself to death, but too many in here agree its detonation for it not to be.
Old 08-29-2017, 10:18 AM
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Originally Posted by ddnspider
having a boost reference or not means exactly jack....if the car is tuned for it. SBCGENII hit it, if the VE or MAF curve is tuned to handle the drop in fuel pressure as boost rises, then its fine. I would have thought there would have been more marks on the piston face if it detonated itself to death, but too many in here agree its detonation for it not to be.
I don't run a maf so my table is stock other than idle because I had issues so I jacked the first box to get it to idle lean enough. how would I scale to table without having a sensor. the stock sensor is only single bar anyways isn't it?
Old 08-29-2017, 10:40 AM
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my plan is to bring it back to the track tomorrow night because it's dead wensdays and give it some fuel and bring springs with me and start it out with no boost and work my way up. I will probably just use my gauge for Checking fuel pressure and build and extension hose into the cab. anouther thing to note is I think my alternator is during because if you wind on it the headlights are dimming. may be a big part of the failure assuming it was doing it that pull
Old 08-29-2017, 10:55 AM
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Originally Posted by Dylanplace
I don't run a maf so my table is stock other than idle because I had issues so I jacked the first box to get it to idle lean enough. how would I scale to table without having a sensor. the stock sensor is only single bar anyways isn't it?
The MAF sensor doesnt know what boost is, only airflow. I have a sticky in the PCM section talking about how to run a MAF on a high hp setup. If you want the PCM to read boost, you'll need to move to a custom OS and a 2 or 3 bar map sensor depending on boost. This is all extra information, all my original post meant was that if the car was tuned originally with the same fuel pressure drop under boost, its not the root cause of your issue unless something has changed.
Old 08-29-2017, 10:59 AM
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Originally Posted by ddnspider
The MAF sensor doesnt know what boost is, only airflow. I have a sticky in the PCM section talking about how to run a MAF on a high hp setup. If you want the PCM to read boost, you'll need to move to a custom OS and a 2 or 3 bar map sensor depending on boost. This is all extra information, all my original post meant was that if the car was tuned originally with the same fuel pressure drop under boost, its not the root cause of your issue unless something has changed.
I'm running 3 bar sd right now. the problem is that I tuned this truck all by myself so I didnt account for fuel pressure drop with boost so I guess I will have to figure out what I need to change to account for that. I only know enough about tuning to get myself in trouble so far haha
Old 08-29-2017, 12:16 PM
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Originally Posted by Dylanplace
I'm running 3 bar sd right now. the problem is that I tuned this truck all by myself so I didnt account for fuel pressure drop with boost so I guess I will have to figure out what I need to change to account for that. I only know enough about tuning to get myself in trouble so far haha
If you tuned the truck with the dropping fuel pressure under boost than you DID account for the fuel pressure drop, you just didnt know it
Old 08-29-2017, 12:43 PM
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Originally Posted by Dylanplace
my actual timing according to hp and my gauge reader is sloped from 20 degrees at 0psi dropping to 15 degrees at 15psi
Is that pump gas or e85? Coz that seems like a lot for pump gas from my limited personal experience


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