krismoriah Posted October 4, 2011 Share Posted October 4, 2011 Hello,I am new to the forum. I have 2 mack dump trucks (2005 granite and 1998 RD688SX) and 1 Ford LTL9000 dump with a 425 cat.On the 1998 RD688SX with an e7-400 on startup there is always a massive amount of white smoke out the exhaust then it clears up. What causes this?The engine has 300,000 miles. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
farmer52 Posted October 4, 2011 Share Posted October 4, 2011 White smoke is usually an indication of unburned raw fuel. It can be caused by too much fuel, low compression, or bad injector(s). Does it smell like fuel or coolant? Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment Share on other sites More sharing options...
rhasler Posted October 4, 2011 Share Posted October 4, 2011 If it is a VMAC I or II (electronically controlled inline pump) it's probably being caused by an immediate lack of oil pressure to the econovance. Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
TOMD Posted October 4, 2011 Share Posted October 4, 2011 x2 Quote Tom ~ Parts & Service SpecialistWatt's Mack Sales, Inc. 1-888-304-6225 Link to comment Share on other sites More sharing options...
EWB555 Posted October 5, 2011 Share Posted October 5, 2011 I was always told White is water, Blue is Oil and Black is Fuel (either too much or lack of air) . My 95 E7 400 with the electronically controlled pump (400,000 Miles) does the same thing but the smoke is more blue then anything. Smokes the whole area out when first started, then if you go down the road and shift a gear or two it clears right up, and doesnt smoke again until you shut it off for at least 20 min then it will smoke again on re-start. The guy I talked to told me its likely the valve guide seals in the heads letting oil leak down into the cylinders when the engine is off, however the truck only used 1.5 gallons between oil changes which doesnt seem like a lot over 16,000 miles given the amount of smoke. Interesting to hear it could be lack out of oil pressure to the econovance-is there something that fixes that or is that inherent to the design? Quote Link to comment Share on other sites More sharing options...
rhasler Posted October 5, 2011 Share Posted October 5, 2011 Nature of the beast. Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
EWB555 Posted October 5, 2011 Share Posted October 5, 2011 Good to know, so maybe I dont have another thing on the list to fix. Quote Link to comment Share on other sites More sharing options...
krismoriah Posted October 5, 2011 Author Share Posted October 5, 2011 Yes it does smell like fuel. I read where it could be lack of oil pressure to the ecovance..isnt there some small screens somewhere behind allen screws that if removed will help? I looked but didnt see any thing like that. It is only on startup..lasts about 5 seconds..then clears up. Quote Link to comment Share on other sites More sharing options...
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