Jbush_51 Posted April 27, 2017 Share Posted April 27, 2017 Got a truck with a 400 e7 Vmac 1. It will shut off going down the road like you turn the switch off. When it does shut off you can turn the key off and back on and it fires back up. Sometimes it takes a couple hours after the truck has been running before it starts acting up. Some days it doesn't do it at all. But when it does start it normally happens every few minutes. I thought it may have been the Ecm so i plugged another one in and it does the same thing. Previous owner had replaced a lot of the sensors including the fuel shut off. The Tachometer recently quit working but not sure if that would have anything to do with it. The truck doesn't have a light in the dash that i know of to see if it has a code. This things has been a pain ever since we bought it . Quote Link to comment Share on other sites More sharing options...
07cl733 Posted April 29, 2017 Share Posted April 29, 2017 I had a similar problem on an etech truck. It turned out to be the main relay on the firewall. It is a large solenoid beside the wiper motor that powers the cab accessories including the computers. 2 Quote Link to comment Share on other sites More sharing options...
Mack log truck Posted May 6, 2017 Share Posted May 6, 2017 I am having the same issue on my '95. I have yet to find a fix, has anyone had any luck? I put a new relay in today and it has not done it yet but I have my doubts that will solve it. Quote Link to comment Share on other sites More sharing options...
fjh Posted May 7, 2017 Share Posted May 7, 2017 It is a large solenoid beside the wiper motor that powers the cab accessories including the computers. Did you replace this sol???? Key to this is next time it happens check to see if the heater is blowing if the heater motor is not working the relay acc solenoid under the dash is toast its under the ash tray to of dash! Quote Link to comment Share on other sites More sharing options...
br549 Posted May 7, 2017 Share Posted May 7, 2017 acc relay is under the ash tray on r and dm models, on ch models they are in the passenger side panel where the fuse box and relays are. Quote Link to comment Share on other sites More sharing options...
Thommy Posted May 25, 2017 Share Posted May 25, 2017 had the same problem for 4 months, checked over multiple times by different people only to find recently a broken earth strap, it was hidden from view as it run down between some electrical conduits Quote Link to comment Share on other sites More sharing options...
Jbush_51 Posted July 11, 2017 Author Share Posted July 11, 2017 No still no luck. I've swapped out the shut off relay and didn't help. I've searched the firewall and can't locate a relay that was mentioned. It still comes and goes it'll go a few weeks and not act up then out of nowhere it starts acting up again for days. I've tried checking the grounds and everyone i've checked has seemed fine. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted July 13, 2017 Share Posted July 13, 2017 Does the engine shut off while the chassis remains powered or is everything dropping out simultaneously? Quote Link to comment Share on other sites More sharing options...
Jbush_51 Posted July 13, 2017 Author Share Posted July 13, 2017 The engine is the only thing that shuts off . And when you cycle the switch it'll fire back up. I changed the solenoid on the firewall and it didn't help. I've went through and replaced all of the breakers in the fuse box thinking maybe that I have a bad breaker and that hasn't helped either. I've wondered if it could be a ground issue but with it firing back up with the cycling of the switch makes me think otherwise. It's getting now when it does shut off it does it about every 10 seconds. Truck sits over night and does fine for the first hour of running and then it starts acting up. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted July 13, 2017 Share Posted July 13, 2017 5 hours ago, Jbush_51 said: The engine is the only thing that shuts off . And when you cycle the switch it'll fire back up. I changed the solenoid on the firewall and it didn't help. I've went through and replaced all of the breakers in the fuse box thinking maybe that I have a bad breaker and that hasn't helped either. I've wondered if it could be a ground issue but with it firing back up with the cycling of the switch makes me think otherwise. It's getting now when it does shut off it does it about every 10 seconds. Truck sits over night and does fine for the first hour of running and then it starts acting up. Your rack controller in the pump is shot. Get engine hot till it begins to snub. Pop the hood and spray the pump controller with cold water from a garden hose. Note if snubbing stops. This is what we use to do at the dealership. Quote Link to comment Share on other sites More sharing options...
Jbush_51 Posted July 14, 2017 Author Share Posted July 14, 2017 I don't mean to sound dumb but what exactly do you mean by snubbing? Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted July 14, 2017 Share Posted July 14, 2017 18 hours ago, Jbush_51 said: I don't mean to sound dumb but what exactly do you mean by snubbing? Not dumb, your just not from the land of Youbetcha. Dying, shutting off, particularly at an idle. I had one customer, with V-Mac II rack travel issues, who juiced his tanks with lubricating oil and said it cleared. A year later I had the pump replacement quote open but he was still running fine? If the hose down works you will need a pump repair. Be real specific about how you found the issue by cooling the pump controller. 1 Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted July 17, 2017 Share Posted July 17, 2017 Could you please let me know if it works? I hate Hitchcock endings. 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted July 17, 2017 Share Posted July 17, 2017 (edited) 14 hours ago, Mack Technician said: Could you please let me know if it works? I hate Hitchcock endings. Agree with that statement Post Your fixes Guys, What ever you working on ,It helps everyone ! and it saves us repeating ourselves ! Also I have seen ECUs that fail under temperature conditions as well The rack actuator condition Mack teck has mentioned is the most common also repining the pump plug sometimes cures this issue! Edited July 17, 2017 by fjh Quote Link to comment Share on other sites More sharing options...
Jbush_51 Posted July 20, 2017 Author Share Posted July 20, 2017 On July 16, 2017 at 9:19 PM, Mack Technician said: Could you please let me know if it works? I hate Hitchcock endings. Will do. It's in its phase of running fine at the moment but I'm sure it will start acting up in a couple weeks. Quote Link to comment Share on other sites More sharing options...
Kwdriver84 Posted August 3, 2017 Share Posted August 3, 2017 I think I have the same issue. I'm driving the the road and it shuts off and gives me the 7-5 code every time. It's sitting at the mack place right now and they are trying to figure out what's the issue. I have notice during the winter season it wouldn't do it but the hotter it gets the more it starts acting up. They adjusted the fuel pump yesterday because they said it was out of adjustment but that didn't fix the issue. What you guys think?? Quote Link to comment Share on other sites More sharing options...
Mack log truck Posted September 6, 2017 Share Posted September 6, 2017 Hey guys, my 1995 cl713 E7 shuts off randomly also. I get blink codes 6-2&6-3 everytime. Usually happens once or twice a day. Almost Always restarts, sometimes i have To cycle the key off multiple times before it will fire up. 8 months and a couple grand later still no fix. And help would be great, thanks. Quote Link to comment Share on other sites More sharing options...
superdog405 Posted September 6, 2017 Share Posted September 6, 2017 I had had some similar issues with my '95 CL. would run fine ,but shut off going down the road. Went on for a year and got progressively worse till one day it quit and would not start at all. On a hunch and lots of $ later, I did the only thing that was left, installed a used Bosch module from a salvage yard and she lit right up, ran for years after with no issue again ! Quote Link to comment Share on other sites More sharing options...
Mack log truck Posted September 7, 2017 Share Posted September 7, 2017 I had had some similar issues with my '95 CL. would run fine ,but shut off going down the road. Went on for a year and got progressively worse till one day it quit and would not start at all. On a hunch and lots of $ later, I did the only thing that was left, installed a used Bosch module from a salvage yard and she lit right up, ran for years after with no issue again ! I barrowed a vmac1 and a fic module from the mack dealer and the problem continued. Its getting very annoying that's for sure! Quote Link to comment Share on other sites More sharing options...
Swishy Posted September 7, 2017 Share Posted September 7, 2017 Had the problem twice sum years ago 1st problem was too much water in the header tank (overfilld) lower the water level to correct level all OK 2nd problem twaz the radiator engine fan was on the way out n shut down ....... fit new fan head = fixd cya §wishy 1 Quote Link to comment Share on other sites More sharing options...
Mps Posted September 7, 2017 Share Posted September 7, 2017 Is the whole electric system shutting down or just motor when it happens how about hitting bumps on road will it do it more or less. 1 Quote Link to comment Share on other sites More sharing options...
Mack log truck Posted October 13, 2017 Share Posted October 13, 2017 The only thing that happens is the truck shuts off, blink code 6-2& 6-3 show up but I do not lose any other electrical power. Quote Link to comment Share on other sites More sharing options...
Randy mckinney Posted October 17, 2017 Share Posted October 17, 2017 (edited) We had same problem changed starter an it fixed it so far. Also check 1939 line. I know starter sounds fishy but it fixed are truck Edited October 17, 2017 by Randy mckinney Quote Link to comment Share on other sites More sharing options...
Weber Tractor Serv. Posted October 18, 2017 Share Posted October 18, 2017 Okay I had this happen to me in a 1996 E7 several times. I replaced the electronic fuel shut off solenoid with a manual pull cable and it solved the problem Quote Link to comment Share on other sites More sharing options...
Mack log truck Posted October 24, 2017 Share Posted October 24, 2017 So today it shutdown and the electronic malfunction light was on, I had over 12 volts going in and coming out of the fuel shut off solenoid. I hopped in the cab and flipped off the speed control switch, the electronic malfunction light shut off and the truck fired up without resetting the key. Quote Link to comment Share on other sites More sharing options...
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