2005 Vision Pos

[peteguy]

I am gonna admit i am not a mack fan but my company purchased a 2005 mack vision caouple years ago and we have problems wondering of someone could help seeing mack saws theres nothing wrong wit it. The truck poors a steady stream of smoke wen under load. the stacks are black, in the morning when u start it up soot comes out of the stacks. The engine fan runs all the time(air clutch) and when the turbo spools it takes atleast 10 seconds.Any help would be apreciated we don't know what to do thanks.

[RowdyRebel]

I am gonna admit i am not a mack fan but my company purchased a 2005 mack vision caouple years ago and we have problems wondering of someone could help seeing mack saws theres nothing wrong wit it. The truck poors a steady stream of smoke wen under load. the stacks are black, in the morning when u start it up soot comes out of the stacks. The engine fan runs all the time(air clutch) and when the turbo spools it takes atleast 10 seconds.Any help would be apreciated we don't know what to do thanks.

Sounds like it could be a bad turbo...I've HEARD Mack had a problem with them for a few years right around the time of V*lv* getting involved and the new emission regs (EGR).....if it isn't pushing as much air into the cylinder as the fuel system is supplying fuel for, it won't all burn. That unburned fuel is leaving the cylinder as the black smoke you see...also noticed by the power NOT being produced by the fuel that is NOT being burned. It could also be a leak in the charge air system, allowing the pressure built up by the turbo to escape before entering the combustion chamber. Does the truck have a boost gauge? If so, what does it read under load?

Not sure about the fan clutch...only experience I have with them is with a log truck...the air line would come loose and the fan WOULDN'T turn on, so you'd be up on the knuckle boom loading a truck, the truck would overheat and shut down, and you'd have to go put the line back on and fire the truck back up to finish loading. Unless the clutch is wore out/sticking and just not disengaging, I'd check for possibly a sensor that could be bad and telling the truck it's running hot even if it isn't. One more thought....there wouldn't happen to be a switch for the fan, would there? I know that log truck had a switch where you could turn it on no matter the engine temp, or with the switch off the fan would come on and off automatically when the engine temps demanded it. The truck I have now, the engine fan switch is on a relay, so the fan shuts off again when the engine temps cool off to 175 degrees.

Now I'm no mechanic either...but I did stay at a holiday in express last night

[fjh]

I am gonna admit i am not a mack fan but my company purchased a 2005 mack vision caouple years ago and we have problems wondering of someone could help seeing mack saws theres nothing wrong wit it. The truck poors a steady stream of smoke wen under load. the stacks are black, in the morning when u start it up soot comes out of the stacks. The engine fan runs all the time(air clutch) and when the turbo spools it takes atleast 10 seconds.Any help would be apreciated we don't know what to do thanks.

has anyone checked the engine for boost leaks!These engines are dirty but a steady stream of black is not normal.Does it have the latest programing?What has been checked if anything?

[peteguy]

Sounds like it could be a bad turbo...I've HEARD Mack had a problem with them for a few years right around the time of V*lv* getting involved and the new emission regs (EGR).....if it isn't pushing as much air into the cylinder as the fuel system is supplying fuel for, it won't all burn. That unburned fuel is leaving the cylinder as the black smoke you see...also noticed by the power NOT being produced by the fuel that is NOT being burned. It could also be a leak in the charge air system, allowing the pressure built up by the turbo to escape before entering the combustion chamber. Does the truck have a boost gauge? If so, what does it read under load?

Not sure about the fan clutch...only experience I have with them is with a log truck...the air line would come loose and the fan WOULDN'T turn on, so you'd be up on the knuckle boom loading a truck, the truck would overheat and shut down, and you'd have to go put the line back on and fire the truck back up to finish loading. Unless the clutch is wore out/sticking and just not disengaging, I'd check for possibly a sensor that could be bad and telling the truck it's running hot even if it isn't. One more thought....there wouldn't happen to be a switch for the fan, would there? I know that log truck had a switch where you could turn it on no matter the engine temp, or with the switch off the fan would come on and off automatically when the engine temps demanded it. The truck I have now, the engine fan switch is on a relay, so the fan shuts off again when the engine temps cool off to 175 degrees.

Now I'm no mechanic either...but I did stay at a holiday in express last night

the fan will be quiet until 190 200 then once it hit that temp it runs full time until u stop and even sometimes it will stay running. THere is a tea kettle sound when u accelerate in low gears without the boost so we are thinking possible air to air pipe leak. there i no on and off for the fan clutch it on a relay and the truck cools to i would guess 175 and it still runs.what sensors to check is the thing i read something about the egr sensors could cause it but not sure.truck boosts up to 30 psi under full throttle. I just shut the truck off earlier and heard an airleak its coming from wats called the vpod valve if anyone wouldknow what this is or wat it does it would be great to know i am young and learning.thanks hope thats more info to go on.p.s. it had the latest programming last year before it went off warranty if thats wat u can call it.

[fjh]

the fan will be quiet until 190 200 then once it hit that temp it runs full time until u stop and even sometimes it will stay running. THere is a tea kettle sound when u accelerate in low gears without the boost so we are thinking possible air to air pipe leak. there i no on and off for the fan clutch it on a relay and the truck cools to i would guess 175 and it still runs.what sensors to check is the thing i read something about the egr sensors could cause it but not sure.truck boosts up to 30 psi under full throttle. I just shut the truck off earlier and heard an airleak its coming from wats called the vpod valve if anyone wouldknow what this is or wat it does it would be great to know i am young and learning.thanks hope thats more info to go on.p.s. it had the latest programming last year before it went off warranty if thats wat u can call it.

If you got a 460 it should be putting out 35 psi or so boost. check for exhast leaks at #no 4 exhast port comon is a broken stud there.Check for boost leaks clamps hoses and after cooler can be suspect.There are lots of difrent things that will cause low boost on these there is a boost by pass tube with a check valve that blows off at 20 psi or better if that is fubar it will cause boost to build slow as well!The valve is mounted at the top where the air enters the engine.Air cleamer is clean?

Check this post out for the fan thing may or may not be related http://www.bigmacktrucks.com/index.php?showtopic=9183

the guy that posted that used to work for mack and is a wizard with the electrics I wish he would hang here more often but I think hes had his fill of Volvo politics!

[RowdyRebel]

the fan will be quiet until 190 200 then once it hit that temp it runs full time until u stop and even sometimes it will stay running. THere is a tea kettle sound when u accelerate in low gears without the boost so we are thinking possible air to air pipe leak. there i no on and off for the fan clutch it on a relay and the truck cools to i would guess 175 and it still runs.what sensors to check is the thing i read something about the egr sensors could cause it but not sure.truck boosts up to 30 psi under full throttle. I just shut the truck off earlier and heard an airleak its coming from wats called the vpod valve if anyone wouldknow what this is or wat it does it would be great to know i am young and learning.thanks hope thats more info to go on.p.s. it had the latest programming last year before it went off warranty if thats wat u can call it.

I have zero experience in EGR trucks....other than driving them. Fan sounds like it is coming on as it should...in the 190 to 200 range...but is just failing to turn off. I'm still thinking either the fan clutch is sticking, or there is a sensor telling the fan not to turn off. One more thought on that...I have a dual PTO set-up on my truck...and after a few months running dumps, the blower PTO wouldn't disengage...had to disconnect the air line to allow the air pressure to the PTO to be released and disengage the PTO....so I installed a tire valve type release to manually release the pressure if and when it would stick (as opposed to digging around and actually finding the cause of the blockage). After a while, the PTO started disengaging on its own without me manually releasing the pressure. Could that be your problem? Maybe a stuck valve not releasing the air pressure or some type of blockage in the line preventing a timely release of air pressure, but after the truck is shut off and sits the pressure can leak off enough to not have the fan still engaged upon start-up? I suppose the easiest way to check that would be to put a pressure gauge of some sort somewhere in the line and drive the truck. When the fan comes on, you should see air pressure in the line. When the fan SHOULD kick off, if the pressure is still in the line it is either a sensor telling the fan to stay on, or a valve not releasing the air pressure. If the air pressure in the line slowly leaks down again the longer the fan should remain off, I would guess the stuck valve...but if the pressure remains constant, look for a sensor. However, if the air pressure drops to zero and the fan remains on, I would guess the problem is a sticking fan clutch.

Again, I'm not a mechanic...just thinking about things I have seen and trying to put pieces together to figure things out without throwing a ton of money at the problem. Nothing but guesswork on my part in this matter...hopefully closer to "educated guess" than "wild guess"....but still just a guess.

[Doug Mitchell]

I'm guessing that this is an air leak somewhere before the turbo. I had 2 aftercoolers crack in a short period on a CH in '91 or so - same whistle, black smoke, lack of power, overheating.

[HK Trucking]

I'm guessing that this is an air leak somewhere before the turbo. I had 2 aftercoolers crack in a short period on a CH in '91 or so - same whistle, black smoke, lack of power, overheating.

A leak before the turbo would allow dirt (unfiltered air) to be drawn in, but would not cause a boost leak.

A leak after the turbo (pipng, boots, CAC, intake manifold gaskets, or that line from the intake manifold to the air compressor) would cause a boost leak.