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5.3 popped at 7psi, why?

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Old 09-10-2012, 05:50 PM
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Several potential factors here. As foose04 stated, on boost, your engine will enter areas of the timing table that a N/A engine won't ever enter (mainly low rpm/ high load areas). I have reduced stock advance by over 15 degrees in some of these areas. You have a good tuner though so I'm sure he Probably reduced advance here. Your IAT sensor reading before boost means that, as you are accelerating, your ECM is actually (likely) increasing advance as the incoming air is cooling down rather than reducing timing because of the heat generated by increased boost. Another thing that has not been mentioned, your injectors look to be too small especially for a returnless system (it is returnless right?). Your injectors could be reaching close to 100% duty cycle. If they are rated 44#@4 bar, they are probably flowing closer to 35# at WOT as your actual rail pressure is more like 50psi rather then 58psi.
Old 09-10-2012, 06:03 PM
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Would also point my finger at IATs... With high air temps, you either break stuff or you go slow. Personally, I prefer to go slow lol....but you can't do that with the sensor in the wrong place.
Old 09-10-2012, 06:56 PM
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Another vote for IAT's, high load, and detonation. I think everyone has pretty much hit the nail on the head, your IAT was most likely climbing up and the sensor was actually telling the PCM it was dropping. Bad combo.
Old 09-10-2012, 10:28 PM
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Originally Posted by Boober
Another thing that has not been mentioned, your injectors look to be too small especially for a returnless system (it is returnless right?). Your injectors could be reaching close to 100% duty cycle.
I should've mentioned it's an '01 truck with the '01 manifold on top of the 06 engine, so it's return style. I think I saw 77% max IDC.

Good points though, thanks.
Old 09-10-2012, 10:48 PM
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Well get her going again and relocate that IAT. I bet it felt good right before it popped. Lots of timing lol
Old 09-20-2012, 09:18 AM
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17* would blow mine up on 6psi, its not whats safe for everyone, its whats safe for the particular car, i put them on the dyno, add timing until torque drops, then back it down a little, thats where the timing wants to be, i have 8* in mine on 9psi, anymore made no more power. at 11* it would start to show little knock.
Old 09-20-2012, 09:22 AM
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probably wasnt the IAT sensor either, i know in my tune stock it wont add timing until 50 degrees so the sensor didnt see that, and with that intercooler your probably 115 degrees and even though its small a short pull wont matter, smaller intercoolers just heat soak faster, now if intake temps were at 150* then i would say thats getting warm. but the fault was your tuner putting it on 17* and with 91 octane that is horrible. a methonal kit would help with octane but your need the timing much lower.
Old 09-20-2012, 09:30 AM
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Im running 23.5* timing on 5psi and some methanol..
Old 09-20-2012, 09:47 AM
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I would check to see when you go into PE mode based on MAP and TPS.
If under load, you can go into boost at low throttle and the system will not go into PE.
I had to set mine really to ( like 40%)

Just throwing out ideas.
Old 09-20-2012, 10:02 AM
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Im running 16* on 12psi on 93. I do plan to pull about 3 degrees but knock on wood its still together and running strong


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