jmax43 Posted December 31, 2008 Share Posted December 31, 2008 I just had my 2001 Vision into the shop because the power would completely shut off and kill the truck. It started once about a year and a half ago, then built up to once a month and progressed to yesterday's 25 to 30 times in 4 hours. It would go about 200 or so yards and just kill. After getting it into the Mack Shop they found there was antifreeze in the ECU. Somehow it came in through the wiring harness, the temperature sending unit was leaking. $3,000.00, a new ECU and wiring harness later, I and the guys at the shop are wondering "WHY?" and "HOW?" Has anyone else ever had any similar problems? I would be very interested to know how this would happen. Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/ Share on other sites More sharing options...
Underdog Posted December 31, 2008 Share Posted December 31, 2008 If your ECM is on the right side of the engine, the coolant line for the compressor runs behind the ECM. If this line leaks, I could see how coolant might get in there. If yours is a later 2001 with the updated ECM, this will not apply, as the ECM is on the other side of the engine. Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28390 Share on other sites More sharing options...
rw613 Posted December 31, 2008 Share Posted December 31, 2008 I HAVE HEARD OF THE NEW MP ENGINES DOING THAT WITH OIL Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28394 Share on other sites More sharing options...
CML Service Posted December 31, 2008 Share Posted December 31, 2008 IH had some problems like that. Thier failure was usually high press oil for the injectors passing through the pressure sensor and following through the wiring to the ECM. They have since changed the design of the injection pressure sensor. Chuck Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28403 Share on other sites More sharing options...
ThaddeusW Posted December 31, 2008 Share Posted December 31, 2008 The thing that gets me is arent those ECM boxes hermetically sealed? The connectors should in fact seal out all moisture, fluids and dirts. If not then blame it on poor or cheap design. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28415 Share on other sites More sharing options...
mackcl96 Posted December 31, 2008 Share Posted December 31, 2008 The thing that gets me is arent those ECM boxes hermetically sealed? The connectors should in fact seal out all moisture, fluids and dirts. If not then blame it on poor or cheap design.Yes they are from outside dirtWhat is happening here is fluid is traveling up the copper wire inside the vinyl covering from a liquid sensor.Very common on throttle position sensor on the P pump Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28417 Share on other sites More sharing options...
Underdog Posted December 31, 2008 Share Posted December 31, 2008 The thing that gets me is arent those ECM boxes hermetically sealed? The connectors should in fact seal out all moisture, fluids and dirts. If not then blame it on poor or cheap design.If a hose or harness rubs against the ECM housing, it can and will wear through. I have seen this several times on different makes of trucks & engines. Just poor workmanship when the truck is put together. Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28418 Share on other sites More sharing options...
Rob Posted December 31, 2008 Share Posted December 31, 2008 Just poor workmanship when the truck is put together.Funny how this did not exist until ownership "across the pond" began to take it's toll.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28419 Share on other sites More sharing options...
Lmackattack Posted December 31, 2008 Share Posted December 31, 2008 another reason why I stick with a Mechanical!!! Sounds like tipical troubles with water getting into places it should not. I can see how water getting into the plug would cause issues but a good connector should keep the water on the outside of the pins and away from the ECM internals. It may be worn wires that are letting water in?Hope you get the problem fixed. Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28420 Share on other sites More sharing options...
DavidT Posted January 1, 2009 Share Posted January 1, 2009 Ok, my first post so here goes.Its not a common problem but it has been an issue with coolant in the EECU. I thought it was limited to just the left hand redesign modules only but about two months ago I made a service call for a customer and this was his problem as well with a EECU mounted on the right side. The most common cause for the coolant leak is the Coolant level sensor. Unlug it and see if there is not coolant in the connector. It leaks internally and creates a wicking condition where the coolant runs down the inside of the wire insulation and into the module. The harness, module, and sensor will have to be changed and they should also add the anti-wicking harness in line at the coolant level sensor. It is a special harness about 12" long that will prevent this in the future in the event of a coolant level sensor failure. Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28488 Share on other sites More sharing options...
dirty dog Posted January 10, 2009 Share Posted January 10, 2009 i have seen this on several unitsi advise all my customers to add the anti capilary harness to all their units with the plastic low coolant level sensor Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-28931 Share on other sites More sharing options...
davekt Posted April 13, 2009 Share Posted April 13, 2009 The main reason coolant gets into the EECU connector is because the Coolant Level Sensor is leaking (because of over torquing the sensor) and the harness acts like a "Garden Hose" the coolant Expansion tank is under pressure usually around 16psi and it pushes the coolant thru the wire insulation to the EECU(Engine Electronic Control Module). There is a "Anti Wicking Jumper Harness just for this condition. Reference Service Bulletin SB273009 Dated 12/16/2005SB__273_009_Coolant_Level_Sensor_Anti_Capillary_Jumper_Harness__Dec__16_2005_.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/7811-antifreeze-getting-into-the-ecu-by-way-of-wiring-harness/#findComment-33695 Share on other sites More sharing options...
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