mackboss Posted October 27, 2010 Share Posted October 27, 2010 I have a 2007 vision ac 427 501000 miles driver was pulling a load down the highway calls with complaint of no power, cant hear the turbo, and the exhaust temp goes to 1250 deg. He goes to a mack dealer pull code 5-9 failure 5, they replace mass flow tube, road test says its ok. The driver starts heading home 5 miles up road same thing, dealer is now closed for the night, driver drops his trailer and bobtails home 150 miles. I plug into it pull codes 4-5 failure 7, 5-9 failure 9, 5-8 failure 9. Did a recal of the VGT ok, road test with air pressure gauge "t"ed into VGT air line, has 90+ psi till it gets about 175 deg then goes to 0 psi and kicks all 3 codes, I replaced the VGT contol valve and the air filter to it road test no different, I have gone through the troubleshooting book for each code everything checks out I even tried a ecm off another truck to try still same result. I getting frustated so any ideas would be great Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/16286-2007-ac427-goes-dead-when-warmed-up/ Share on other sites More sharing options...
fjh Posted October 27, 2010 Share Posted October 27, 2010 I have a 2007 vision ac 427 501000 miles driver was pulling a load down the highway calls with complaint of no power, cant hear the turbo, and the exhaust temp goes to 1250 deg. He goes to a mack dealer pull code 5-9 failure 5, they replace mass flow tube, road test says its ok. The driver starts heading home 5 miles up road same thing, dealer is now closed for the night, driver drops his trailer and bobtails home 150 miles. I plug into it pull codes 4-5 failure 7, 5-9 failure 9, 5-8 failure 9. Did a recal of the VGT ok, road test with air pressure gauge "t"ed into VGT air line, has 90+ psi till it gets about 175 deg then goes to 0 psi and kicks all 3 codes, I replaced the VGT contol valve and the air filter to it road test no different, I have gone through the troubleshooting book for each code everything checks out I even tried a ecm off another truck to try still same result. I getting frustated so any ideas would be great ThanksI would try building a plate for under the egr valve and tri it I think what you got is and egr valve thats failing to close! Quote Link to comment https://www.bigmacktrucks.com/topic/16286-2007-ac427-goes-dead-when-warmed-up/#findComment-65893 Share on other sites More sharing options...
mackboss Posted November 22, 2010 Author Share Posted November 22, 2010 (edited) I have a 2007 vision ac 427 501000 miles driver was pulling a load down the highway calls with complaint of no power, cant hear the turbo, and the exhaust temp goes to 1250 deg. He goes to a mack dealer pull code 5-9 failure 5, they replace mass flow tube, road test says its ok. The driver starts heading home 5 miles up road same thing, dealer is now closed for the night, driver drops his trailer and bobtails home 150 miles. I plug into it pull codes 4-5 failure 7, 5-9 failure 9, 5-8 failure 9. Did a recal of the VGT ok, road test with air pressure gauge "t"ed into VGT air line, has 90+ psi till it gets about 175 deg then goes to 0 psi and kicks all 3 codes, I replaced the VGT contol valve and the air filter to it road test no different, I have gone through the troubleshooting book for each code everything checks out I even tried a ecm off another truck to try still same result. I getting frustated so any ideas would be great ThanksAfter 3 trips to the local dealer, 1 VGT valve, 2 mass flow tubes, reflash of ecm, replacement of pins on ecm, 1 egr valve, multipule calls to mack help line, and 1200 miles roadtesting and trials the problem has been found. About 10" up the harness from the ground stud on left side of engine block was a break in the wire that would make contact then not. Now ready for the mastercard commercial on what this will cost and money lost in loads lost. Edited November 22, 2010 by mackboss Quote Link to comment https://www.bigmacktrucks.com/topic/16286-2007-ac427-goes-dead-when-warmed-up/#findComment-67155 Share on other sites More sharing options...
fjh Posted November 22, 2010 Share Posted November 22, 2010 After 3 trips to the local dealer, 1 VGT valve, 2 mass flow tubes, reflash of ecm, replacement of pins on ecm, 1 egr valve, multipule calls to mack help line, and 1200 miles roadtesting and trials the problem has been found. About 10" up the harness from the ground stud on left side of engine block was a break in the wire that would make contact then not. Now ready for the mastercard commercial on what this will cost and money lost in loads lost.What did that wire control? Quote Link to comment https://www.bigmacktrucks.com/topic/16286-2007-ac427-goes-dead-when-warmed-up/#findComment-67178 Share on other sites More sharing options...
mackboss Posted November 23, 2010 Author Share Posted November 23, 2010 (edited) What did that wire control?the ground for the VGT control valve. I found out today the dealer also threw a turbo at it also (which bolts backed off and blew the gasket out) Edited November 23, 2010 by mackboss Quote Link to comment https://www.bigmacktrucks.com/topic/16286-2007-ac427-goes-dead-when-warmed-up/#findComment-67222 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.