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2014 CHU with an MP8, seems to be low on power and boost.


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1 hour ago, Onyx610 said:

I have never seen more than 35 psi. However I have heard a lot of talk about 38-40psi so I thought I was wrong…

I’ve seen a few hit 35 them back off to 33 and be good. I’ll talk to my buddy that has the 505Plus program in a CHU and see what he’s hitting. The only ones I have seen in the 38-40 range had issues with the turbo. Which can be good in some cases if the sticks in the right position. 

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15 minutes ago, Mackpro said:

88800265. It’s about $63 from Mack 

So it looks to me  they have been using the parts canon to a great degree here! I'm not the guru here how ever! A question for( MP or OXY  )do you have to do a learned data reset with a turbo change?

Also don't see anywhere where they checked the valve set are Engine brake slaves OK?  That said the truck hasn't been asking to frequent regens which would accompany a turbo issue usually!  if so wonder if they are doing so!

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13 minutes ago, fjh said:

So it looks to me  they have been using the parts canon to a great degree here! I'm not the guru here how ever! A question for( MP or OXY  )do you have to do a learned data reset with a turbo change?

Also don't see anywhere where they checked the valve set are Engine brake slaves OK?  That said the truck hasn't been asking to frequent regens which would accompany a turbo issue usually!  if so wonder if they are doing so!

Yes with a new turbo a learned data reset should be performed through PTT. When people post problems and say the dealership is working on their truck I just figure they know this stuff and it was done? I’ve never worked at a dealership so not sure. 

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12 minutes ago, Onyx610 said:

Yes with a new turbo a learned data reset should be performed through PTT. When people post problems and say the dealership is working on their truck I just figure they know this stuff and it was done? I’ve never worked at a dealership so not sure. 

I to assume they are doing the right things! That said when I see the parts cannon being used I sometimes wonder!?

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1 minute ago, Mackpro said:

Always do learned data reset when changing most any engine part. On the newer trucks it’s called Adaptive Factor Reset under calibrations in Tech Tool 

Good info, didn’t know you should do that for most things. 

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4 minutes ago, fjh said:

I to assume they are doing the right things! That said when I see the parts cannon being used I sometimes wonder!?

I think that happens more often than not anymore. Not to many guys like Mackpro around that correctly diagnose and pin point the problem. 

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5 minutes ago, Onyx610 said:

There’s doctors and then there’s surgeons…

Agreed! Some are just nurses ! Some just plain Parts Chuckers! And some times you need to go with your best guess we all been there ! That said comes down to Experiences !More experience more knowledge  gained!  We had a few guys that had a real decent handle on what the ECU wanted to see and went in search of the parameters before pulling out the Parts cannon and usually even if the engine was deleted could get to a reasonably quick repair!  But you have to be reasonably good at listening to what the operator is saying and sometimes they don't reveal the whole story ! We see it here All the time! Only part of the story!

Edited by fjh
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When this truck is right boost runs up to 39 to 40 and holds till it starts dropping in the toque curve at 1650 or so . If its hot out , above 85 degrees i see a lil softening of the upper boost to about 38 but almost always above 35 psi.

I'm with you on the grey hair and bald spot. nuthin better than talking to experience!

 

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I got to test drive the truck I been working on for a couple of days before I went home today. 2012 CXU  445 Econodyne. 10 speed Fuller. New turbo , new EGR differential sensor upgrade kit installed, new EGR temp sensor, no boost leaks, clean DPF with only 1% soot . Pulling a empty but heavy feed trailer . On the interstate coming up the biggest long hill we have around here. I accelerate up the hill and took this pic at  1650 rpms at 72 mph  and max boost I got was 33 psi , I hit 75 at the top of the hill. I’m wondering if emission years and HP differences make a big difference in actual max Boost pressure. My buddy who had the 2016 505 Plus program can’t remember his boost numbers in a hard pull. I road with him once to the grainery and we we’re pulling same hill loaded  easier that I pulled it with my empty trailer. Gross weight was 101,000 when we weighed at the grain bins. Best pulling Mack I ever road in. 

CD7C14E8-FF51-420D-8C0F-4945359A4364.jpeg

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10 hours ago, Mackpro said:

I got to test drive the truck I been working on for a couple of days before I went home today. 2012 CXU  445 Econodyne. 10 speed Fuller. New turbo , new EGR differential sensor upgrade kit installed, new EGR temp sensor, no boost leaks, clean DPF with only 1% soot . Pulling a empty but heavy feed trailer . On the interstate coming up the biggest long hill we have around here. I accelerate up the hill and took this pic at  1650 rpms at 72 mph  and max boost I got was 33 psi , I hit 75 at the top of the hill. I’m wondering if emission years and HP differences make a big difference in actual max Boost pressure. My buddy who had the 2016 505 Plus program can’t remember his boost numbers in a hard pull. I road with him once to the grainery and we we’re pulling same hill loaded  easier that I pulled it with my empty trailer. Gross weight was 101,000 when we weighed at the grain bins. Best pulling Mack I ever road in. 

CD7C14E8-FF51-420D-8C0F-4945359A4364.jpeg

Good possibility the boost sensor could change the Game! We accidently installed a MP 8 boost sensor in an MP10 once ! That truck turned from mild mannered Clark Kent to Super man in an instant ! It was a low bed tractor that you could pull stumps with! Truck was still under warranty so we didn't leave it  like that but it was and Eye opener!

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