Turbo 5.3 possible tune issues
Thread Starter
On The Tree
Joined: Jul 2012
Posts: 111
Likes: 0
From: tulsa, ok
To get the reading you subtract barometric pressure in my particular area around 95-100kpa is 0 vacuum. My boost gauge reads 10psi peak. My tune shows 135kpa at Max boost 135-100 is 35kpa which is roughly 5psi definitely something off.
Last edited by bbowerman; May 16, 2018 at 06:12 PM.
Thread Starter
On The Tree
Joined: Jul 2012
Posts: 111
Likes: 0
From: tulsa, ok
Okay guys had the wrong map sensor logging (2bar) It was the vcm scanner I redid it and it now shows 164kpa is Max boost. So I scaled the boost enrich way up because I was seeing incorrect info pulled fuel out of the boost enrich about to test my theory. EDIT that was the issue, it was going rich and trying to foul the plugs going into the 10afr at 4psi and it kept getting richer on the way up so it felt weak up top, then I was having to free rev it to clean the plugs afterwards. Now to add a little timing.
Last edited by bbowerman; May 16, 2018 at 07:49 PM.
Thread Starter
On The Tree
Joined: Jul 2012
Posts: 111
Likes: 0
From: tulsa, ok
I know right, I hate that. I usually try to break it down where it is easier on the eyes. Guess I'm gonna hook up the methanol and start doing some more work. I appreciate all the insight. Who knows maybe this thread will help someone else.
Originally Posted by Fuhnortoner
70kPa at Idle? So youre boosting at idle?
If you meant -70kPa you have a vacuum leak.
If you truly meant 70kPa, your MAP sensor is probably fucked, or the calibration for it is fucked. If youre MAP says youre boosting 130 and your boost gauge says 10psi, youre probably dumping too much fuel, which explains the power loss and backfiring.
If you meant -70kPa you have a vacuum leak.
If you truly meant 70kPa, your MAP sensor is probably fucked, or the calibration for it is fucked. If youre MAP says youre boosting 130 and your boost gauge says 10psi, youre probably dumping too much fuel, which explains the power loss and backfiring.
For the op, do key on engine off and see what the map reads. Should be right around 100kpa, if not I'd double check the values you have for the map offset.
Oops I guess I should have kept reading, didn't realize it was already fixed.
Launching!
Joined: Apr 2017
Posts: 276
Likes: 5
From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Lol -70kpa? 70kpa is still vacuum, I'm not sure you understand how kpa works.
For the op, do key on engine off and see what the map reads. Should be right around 100kpa, if not I'd double check the values you have for the map offset.
Oops I guess I should have kept reading, didn't realize it was already fixed.
For the op, do key on engine off and see what the map reads. Should be right around 100kpa, if not I'd double check the values you have for the map offset.
Oops I guess I should have kept reading, didn't realize it was already fixed.
Last edited by Fuhnortoner; May 17, 2018 at 07:18 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Launching!
Joined: Apr 2017
Posts: 276
Likes: 5
From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Ok so I admit i was wrong about kPa. I understand it now. But I did call it.
So put that in your pipe and smoke it.
70kPa at Idle? So youre boosting at idle?
If you meant -70kPa you have a vacuum leak.
If you truly meant 70kPa, your MAP sensor is probably fucked, or the calibration for it is fucked. If youre MAP says youre boosting 130 and your boost gauge says 10psi, youre probably dumping too much fuel, which explains the power loss and backfiring.
If you meant -70kPa you have a vacuum leak.
If you truly meant 70kPa, your MAP sensor is probably fucked, or the calibration for it is fucked. If youre MAP says youre boosting 130 and your boost gauge says 10psi, youre probably dumping too much fuel, which explains the power loss and backfiring.
So put that in your pipe and smoke it.
Easy dude, we're just messing around. Everyone who understood kPa in a stock PCM figured it was either a crap map or an issue in the tune. No stockish 5.3 idles at 70kPa....as per my 1st post.
Launching!
Joined: Apr 2017
Posts: 276
Likes: 5
From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
