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Dar

2005 mack aset low power.

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Hi guys. I have a 2005 mack vision with an aset engine, been running it on the farm for a couple years. Always thought it was a bit low on power and boost was a bit high but it worked so I just kept driving. This fall however on my way home one night I could not get up to 60mph on the highway. Since then I can only get up to highway speed empty and even then the boost is continually 25-30 psi. Loaded I cannot get up to highway speed and boost rises as high as 33ish psi. There are a few codes present.

9-5.  Compressor discharge temp sensor

2-5. Front drive axle temp 

2-6. Rear drive axle temp

3-1. Exhaust temp sensor

All these codes were present before this new problem came up. Truck is fully serviced including new air filter and fuel filter. As soon as I get to town I will pick up some fittings so I can check the fuel pressure after the fuel lift pump. Also have a sensor coming for the turbo discharge temp code. If you have any suggestions I would be happy to hear. Thanks. 

I was reading a post from a few years ago of about an 03 model with what seems to be very similar problems. 

Screenshot_20200109-145847_Samsung Internet.jpg

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You can download the v-mac III service manual here.

https://macktrucks.vg-emedia.com/ProductDetail.aspx?ProductId=6156

Just click the view file hyperlink and it will download, at the end of the manual you will see troubleshooting steps for your codes. As for lack of power i dont have much experience on what may be the issue but anything sensor related can be found in the manual.

Edited by ivanuke

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1 hour ago, Dar said:

Hi guys. I have a 2005 mack vision with an aset engine, been running it on the farm for a couple years. Always thought it was a bit low on power and boost was a bit high but it worked so I just kept driving. This fall however on my way home one night I could not get up to 60mph on the highway. Since then I can only get up to highway speed empty and even then the boost is continually 25-30 psi. Loaded I cannot get up to highway speed and boost rises as high as 33ish psi. There are a few codes present.

9-5.  Compressor discharge temp sensor

2-5. Front drive axle temp 

2-6. Rear drive axle temp

3-1. Exhaust temp sensor

All these codes were present before this new problem came up. Truck is fully serviced including new air filter and fuel filter. As soon as I get to town I will pick up some fittings so I can check the fuel pressure after the fuel lift pump. Also have a sensor coming for the turbo discharge temp code. If you have any suggestions I would be happy to hear. Thanks. 

I was reading a post from a few years ago of about an 03 model with what seems to be very similar problems. 

Screenshot_20200109-145847_Samsung Internet.jpg

Compressor discharge temp indicates the hood to air cleaner boot is not sealing sucking in engine compartment heat!!!!!! Fix the boot And see what happens!

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Currently the wires are ripped off right at the sensor. So the sensor will need to be replaced first. 

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And when did you last change your fuel filters?

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Clogged fuel filter still let's you hit good boost numbers, up until a continually decreasing rpm as the filter becomes more and more clogged.

Basically acts like a governor.

Edited by JoeH

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37 minutes ago, Dar said:

Fuel filter is brand new. 

Check your tanks, I remember my CHN had similar issue, I changed fuel filter and didnt help. I drained my entire tank both sides and refilled with new diesel, that fixed the issue.

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Would the variable geometry turbo be stuck in wrong position?

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Thanks guys. My fan clutch locked up the other day which isnt nice when it is -25 Celsius. Should have that back together tomorrow and the turbo temp sensor should be in too. Will see what that does. 

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