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Contributor

Re: cat 315 boost sensor reading negative 8

[ Edited ]

if the air inlet has no restrictions and the turbo boost is abnormal, make sure your turbo is really working under load and also make sure your exhaust system has no restriction that prevent the turbo from turning fast enough to produce proper boost.
 
an engine with a bad turbo or experience an exhaust restriction is more likely to develop symptoms under load but will barely shows any symptoms on idle.

 

Contributor

Re: cat 315 boost sensor reading negative 8

315D L EXCAVATOR JGS00244

 

Inlet Air Restriction,Exhaust Restriction and/or High Altitude

 

  • Measure the inlet manifold (boost) pressure while the engine is operating under load.  
  • Replace any blocked air filters and/or remove any obstructions from the air inlet. Check for a restriction in the exhaust system.
  • Check air cleaner to turbocharger pipe
  • Check aftercooler to turbocharger air pipe 
  • Make sure that the settings for the engine are correct for the altitude.

 

Reduced Flow of Inlet Air through the Aftercooler

 

  • Check for contamination in the air pipe that connects the turbocharger to the aftercooler.
    • Clean all contaminated air inlet pipes or replace all contaminated air inlet pipes. 
    • Service the air cleaner and replace the air cleaner element. 
    • If contamination is found in the air pipe from the turbocharger to the aftercooler, check all of the air inlet pipes upstream of the turbocharger for leaks.  
  • If oil is found in the air pipe, inspect the turbocharger compressor housing and inspect the outlet from the turbocharger compressor for oil.
    • If oil is found in the inlet to the turbocharger compressor housing, the oil originates from the engine crankcase breather.

       

    • If oil is found in the outlet from the turbocharger compressor housing but oil is not found in the inlet to the compressor housing, the oil originates from the seals for the turbocharger bearings.

Part Number:

281-3526 
 AFTERCOOLER AS

 

Most likely the problem is not the aftercooler itself but it should be throughly inspected too.

Replace your air filters, so that will eliminate any possible restriction there and check all of the above.

 

Cold air is denser than hot air, does the engine overheats?

New member

Re: cat 315 boost sensor reading negative 8

Jgs00244 is the serial number.
Sorry I misspoke. We have replaced the hose from air intake to air cooler. Not the air cooler to turbo

I agree it seems as if there is a blockage in the air cooler somehow but seems really strange. This machine will start fine and idle for an hour while it warms up then only start screwing up once you are working. Does anyone know a part number for the air cooler or have a schematic of the inside of it? Having a real rough time trying to find that.
Contributor

Re: cat 315 boost sensor reading negative 8

serial number?

Regular Contributor

Re: cat 315 boost sensor reading negative 8

If the hose from the air cooler to the air intake on the engine was being sucked flat when the engine stalls and also stalls with hose from turbo to air cooler off this indicates a restriction within the aftercooler itself. Why the engine runs ok under load at speed  but then stalls when load and speed are reduced is unusual. Suggest you either measure the pressure drop across the aftercooler to confirm problem or just replace it.

New member

cat 315 boost sensor reading negative 8

Here is a corker wally....

 

So while running our 2011 cat 315 with no problems, out of the blue while the auto idle is engaging, the engine bogs down spits white smoke and has a boost reading of negative 8.  After a long story and 3 tech visits we have replaced the throttle dial, the boost sensor (new one still reads negative 8/9 when engine bogs down.  I should say engine runs fine as long as its under load.  The colder it is the less frequent the problem (it will idle down sometimes).  the hotter it gets the more frequent it will bog out when load is reduced.  only way to get rpms up again is shut the machine off and turn on again.  the hotter it is the longer it we have to wait to start it again   Latest tech noticed the hose from the air cooler to the air intake on the engine was being sucked flat when the engine bogged down.  took hose from turbo to air cooler off and still bogged, plus works great when high rpms, so not the turbo.  Have just replaced the hose from turbo to air cooler but dont think that needed to be done, nothing seemed wrong with the one we replaced.  we will see tomorrow .  any ideas.  thanks