Debugging slightly low boost
Thread Starter
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More Turbo
Joined: Oct 2013
Posts: 584
Likes: 1
A boost leak can show itself at low pressure, but you have to really look for it. I had about 5 PSI and the Simple Green bubbles out the intake plenum seal looked minor - but I can only speculate what it would have looked like if I had 20 or 30 PSI boost going on. I know for sure that the subtle bubbles were gone after replacing the plenums, and my boost/EBP/EGT numbers showed an obvious improvement.
Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
Now that you've driven it a ways, look in the back with a flashlight (engine off and cool is easiest) for soot anywhere, especially at any joints.
A buddy's borrowed boost leak detector (PVC cap with air hose connection and gauge) and air compressor dialed down to 30psi helped me find a leak in the passenger side boot to the manifold intake plenum, and then in the plenum itself
I'm waiting for a set of billet manifold intake plenums from Beans to arrive.
No specific problems, but towing up a long steep hill, 50-60mph was about it and it seemed like it should have more so I started looking....and logging...and posting, LOL.
Here's the first part, before I did the leak test (intake side). Compare the graphs to your own.
https://www.ford-trucks.com/forums/1...om-pid-3d.html
There is also a good pic of a suggestion for testing the exhaust side.
I'm waiting for the plenums to arrive and installed before more leak checking. Most of it will be coming off anyways
Thread Starter
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More Turbo
Joined: Oct 2013
Posts: 584
Likes: 1
I'll try to get some good photos of the back of the turbo in order to see if anything's going on back there.
Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
You can see that in my pics of the boot. It has an orange stripe where the clamp was
That was your leak detector? Well then...thanks for the suggestion! LOL.
Yeah, look for some soot. I may have more leaks, didn't really check the uppipes yet- planning on using the tailpipe method
Thread Starter
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More Turbo
Joined: Oct 2013
Posts: 584
Likes: 1
Here's a chart. First to second gear. Not full throttle but hard acceleration. I also have Intake and Manifold temps in the chart. I'm not positive what conditions we want to check them under. X Axis is minutes:seconds.tenths
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Man... your EBP is all over the place in every chart and data set I see. Something is leaking - no way around it.
When I had this, I had to bear down and get serious about looking for leaks. Only then did I find mine.
Of course, nothing says it can't be an internal air leak (heaven forbid).
When I had this, I had to bear down and get serious about looking for leaks. Only then did I find mine.
Of course, nothing says it can't be an internal air leak (heaven forbid).
Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
I believe this is Rich's opinion, too, though he may not yet be ready to stick a pin in that conclusion. I'm convinced, but he has a tad more experience with this than I do, LOL.
Did you look at my "Sluggish" thread? Concentrate on the EBP pattern and compare it to yours. Then see what happened when I found and corrected an exhaust leak. See the difference?
That's what you want to see happen
Thread Starter
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More Turbo
Joined: Oct 2013
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I need another strategy to find it. No soot, no psssst sounds.
I do have those small bubbles on the manifold, but no soot, I'm still not convinced its an issue - I would even argue that the gap might close once everything is heated up and expands....
On thing I still don't understand is how a small hard to detect pinhole in the exhaust side can cause huge problems when at the same time the wastegate is open with a hole 100x larger.
What about this for a test:
Cover each joint with fiberglass and metal tape or wire, then look for dirty fiberglass (soot on exhaust side, oil on intake sides)?
I do have those small bubbles on the manifold, but no soot, I'm still not convinced its an issue - I would even argue that the gap might close once everything is heated up and expands....
On thing I still don't understand is how a small hard to detect pinhole in the exhaust side can cause huge problems when at the same time the wastegate is open with a hole 100x larger.
What about this for a test:
Cover each joint with fiberglass and metal tape or wire, then look for dirty fiberglass (soot on exhaust side, oil on intake sides)?
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Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
Thread Starter
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More Turbo
Joined: Oct 2013
Posts: 584
Likes: 1
If I understand how these work, the wastegate will start to open at about 5 PSI and then be fully open well before we hit max boost. This helps the turbo spool up faster while preventing overboost at higher RPMs.
Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
I had a boost sensor go bad and had NO performance or boost. Just happened to occur when rebuilding my turbo. Talk about a letdown
Replaced it and back to normal.
Keep in mind, your turbo should be able to build about DOUBLE the boost you're seeing. Just because you are seeing decent boost doesn't mean you don't have leaks that are causing problems.
For example, if your turbo has to spin faster, enough to make 23psi, but you are only getting 14psi, that's a pretty noticeable problem. Among other things, it messes up your power/efficiency curves
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Yes, I strongly suspect the intake. An exhaust leak would make the EBP/MAP much closer to each other.
Post Fiend
Joined: Sep 2006
Posts: 7,426
Likes: 6
From: Sioux Falls, SD
yep, It (EGT's) should be lower......still wondering if there is a chip or tune installed. can you monitor FIPW (fuel injector pulse width)?
Is it a smooth steady boost climb or does she pop up to 14-15 in a second?
- plus data log FIPW, ICP, ICP duty cycle, rpm's, MAP, speed, EBP, & oil temp from 55-80 mph in OD (about 20-30 seconds worth of data). Then e-mail the data to one of us to plug it into ExPaCamper's PID 3D software.
Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
TJMike,
Can you fill in your signature with your truck's info and any non-stock info? It does make it easier to keep track- especially when several similar threads are going at the same time
Also- I put my tuner on yesterday and am starting to push my Excursion a bit. Some things are starting to show up. We'll be analyzing it to death and try to document as much as possible as we go.
Might be helpful to you. Ask any Q's you like about it.
https://www.ford-trucks.com/forums/1...with-logs.html
Can you fill in your signature with your truck's info and any non-stock info? It does make it easier to keep track- especially when several similar threads are going at the same time
Also- I put my tuner on yesterday and am starting to push my Excursion a bit. Some things are starting to show up. We'll be analyzing it to death and try to document as much as possible as we go.
Might be helpful to you. Ask any Q's you like about it.
https://www.ford-trucks.com/forums/1...with-logs.html