strange piston failure?
Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
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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
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
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.
Thread Starter
Staging Lane
Joined: May 2017
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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.
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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.
Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
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Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
Likes: 0
I'm running id850 injectors. only using about 40% I can check some logs though
9 Second Club
Joined: Nov 2003
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From: Norn Iron
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
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.
Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
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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.
Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
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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
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.
Thread Starter
Staging Lane
Joined: May 2017
Posts: 66
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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
