Richardsmack Posted June 21, 2023 Author Share Posted June 21, 2023 1 hour ago, Joey Mack said: on the fire wall, by the steering column, is a gray wire with 2 or more wires. it has a triangular weatherpack plug on it... are the contacts and wires in good condition? that is the 1939 line under the hood.. it is part of the engine harness.. here is an example from the engine I currently have in my shop. Thanks Joey. Those wires I connected to 2 new temporary wires to the ecu as a test. No difference.. So I put everything back like it was. I'm thinking to buy the nexio usb link 2 with the 6 pin cable. What I saw is that the v-mac software is free Version 2.9.2. Only problem would be to get the proper config files for my vin#? Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533400 Share on other sites More sharing options...
Joey Mack Posted June 21, 2023 Share Posted June 21, 2023 did you check the voltages at the Diag. port under the dash? there is a low side voltage and a high side voltage.. you should have a gray 6 pin port.. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533401 Share on other sites More sharing options...
Joey Mack Posted June 21, 2023 Share Posted June 21, 2023 I beleive you have an E-Tech engine... 6 EUP's not a Robert Bosch inj. pump??? Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533402 Share on other sites More sharing options...
Richardsmack Posted June 21, 2023 Author Share Posted June 21, 2023 22 minutes ago, Joey Mack said: I beleive you have an E-Tech engine... 6 EUP's not a Robert Bosch inj. pump??? It's the 6 pin connector. E tech engine yes. e7-350. Everything was working until water came into the vecu. Replaced it with a used onne with same #'s. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533405 Share on other sites More sharing options...
Joey Mack Posted June 21, 2023 Share Posted June 21, 2023 ok.. I remember you took the VECU apart and cleaned it.. This is a hard one to fix on here.. Have you added a ground wire from the EECU housing, under a mount bolt to a clean spot on the engine.. I have had to do that several times to create a needed ground.. I wish I was much smarter about ECU issues and backdoor repairs.. Sorry Bud.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533406 Share on other sites More sharing options...
Richardsmack Posted June 21, 2023 Author Share Posted June 21, 2023 5 minutes ago, Joey Mack said: ok.. I remember you took the VECU apart and cleaned it.. This is a hard one to fix on here.. Have you added a ground wire from the EECU housing, under a mount bolt to a clean spot on the engine.. I have had to do that several times to create a needed ground.. I wish I was much smarter about ECU issues and backdoor repairs.. Sorry Bud.. Jojo Will try an extra ground. Thanks. Will post when It works or if I find a solution. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533407 Share on other sites More sharing options...
Mackpro Posted June 22, 2023 Share Posted June 22, 2023 Joey is correct, sounds like a J1939 high speed data link issue. The truck is running on the low speed data link J1587 so that’s why there is a delay between key off and actual engine shutdown. The J1939 wires are always twisted green and yellow wires. Sometimes it will have a third wire which is a shielding wire. The used VECU should work even though it’s the wrong VIN. But will have to reset parameters such as , road speed limit, tire size , rear gear ratio and trans top gear ratio. The HP level is only in the engine ECM. I wish I had seen this post way earlier. All R-series trucks with ETECH engines had their VECU’s mounted with the connectors facing up. And a Joey said the windshields leak right into them. The first sign of any weird issues, this is the first place to check ( on a R-series). It would have been nice to get the VECU programed to match your truck . But if the Tech was not 100% confident then it’s probably best he didn’t. Programing VMAC 3 ECM’s is a multi step process and one wrong move and you turn the ECM into a paper weight. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-533433 Share on other sites More sharing options...
Rickvr Posted July 15, 2023 Share Posted July 15, 2023 On 6/22/2023 at 9:09 AM, Mackpro said: Joey is correct, sounds like a J1939 high speed data link issue. The truck is running on the low speed data link J1587 so that’s why there is a delay between key off and actual engine shutdown. The J1939 wires are always twisted green and yellow wires. Sometimes it will have a third wire which is a shielding wire. The used VECU should work even though it’s the wrong VIN. But will have to reset parameters such as , road speed limit, tire size , rear gear ratio and trans top gear ratio. The HP level is only in the engine ECM. I wish I had seen this post way earlier. All R-series trucks with ETECH engines had their VECU’s mounted with the connectors facing up. And a Joey said the windshields leak right into them. The first sign of any weird issues, this is the first place to check ( on a R-series). It would have been nice to get the VECU programed to match your truck . But if the Tech was not 100% confident then it’s probably best he didn’t. Programing VMAC 3 ECM’s is a multi step process and one wrong move and you turn the ECM into a paper weight. The wires are good. Meantime still stuck. Ordered nexiq usb link 2 but happened to be a none working clone. I'm out of options and will never go back to that mack so called dealer. What will be a good affordable device/scanner to use. I have the mack programming software.. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-534888 Share on other sites More sharing options...
Rickvr Posted July 15, 2023 Share Posted July 15, 2023 11 minutes ago, Rickvr said: The wires are good. Meantime still stuck. Ordered nexiq usb link 2 but happened to be a none working clone. I'm out of options and will never go back to that mack so called dealer. What will be a good affordable device/scanner to use. I have the mack programming software.. Thanks. Maybe there is something wrong with the used VECU I bought.... Pfff. If I only could try a different one. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-534889 Share on other sites More sharing options...
Mackpro Posted July 15, 2023 Share Posted July 15, 2023 (edited) If your having the same issue with both VECU then probably a wiring issue. If you have a ABS ecm next to the VECU, unplug the ABS ecm. Find the yellow and green wires . Using a ohm meter and with key in off position. You should have 60 ohms across the 2 wires. With the key on you should 2.5 or more volts on the yellow wire to ground. On the green wire you should have 2.5 volts or less. The green is the low side and the yellow is the high side . The more data that’s being transmitted the higher the high side voltage goes and the lower the low side goes. Edited July 16, 2023 by Mackpro 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-534895 Share on other sites More sharing options...
Rickvr Posted July 16, 2023 Share Posted July 16, 2023 On 7/15/2023 at 11:54 AM, Mackpro said: If your having the same issue with both VECU then probably a wiring issue. If you a a ABS ecm next to the VECU, unplug the ABS ecm. Find the yellow and green wires . Using a ohm meter and with in off position. You should have 60 ohms across the 2 wires. With the key on you should 2.5 or more volts on the yellow wire to ground. On the green wire you should have 2.5 volts or less. The green is the low side and the yellow is the high side . The more data that’s being transmitted the higher the high side voltage goes and the lower the low side goes. Thanks will try that! Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-534978 Share on other sites More sharing options...
Rickvr Posted August 7, 2023 Share Posted August 7, 2023 On 7/16/2023 at 12:08 PM, Rickvr said: Thanks will try that! voltages and resistance are just like you said. im trying to find a vecu but no luck. meantime i use it like it is as i have to work. it has way less power which is shit. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-536424 Share on other sites More sharing options...
mowerman Posted August 7, 2023 Share Posted August 7, 2023 havent been following since i really dont have suggestions have to give hats off to your pail invention ingenious just spotted it.dont throw the rest of it out,,,,,it may double as a welding helmet...good luck bud...bob Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-536517 Share on other sites More sharing options...
Rickvr Posted August 11, 2023 Share Posted August 11, 2023 On 8/7/2023 at 7:30 PM, mowerman said: havent been following since i really dont have suggestions have to give hats off to your pail invention ingenious just spotted it.dont throw the rest of it out,,,,,it may double as a welding helmet...good luck bud...bob Thanks😃 some progress finally. got the scantool and it works! the vin in the ecu is not from my truck but it's for a e7 350. now im looking for someone with access to the mack dealer portal to get the proper files to program the ecu and vcu to my vin#. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-536789 Share on other sites More sharing options...
Rickvr Posted August 11, 2023 Share Posted August 11, 2023 Not the ecu of my truck original :-) over 2 million miles.... and the look at the fuel used Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-536791 Share on other sites More sharing options...
Rickvr Posted August 16, 2023 Share Posted August 16, 2023 So my vecu is the 12MS48M4/12MS411M4. I can't find one. Would it matter if I put a 12MS48M6/12MS411M6 in? Thanks for your reply. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-537122 Share on other sites More sharing options...
Mackpro Posted August 17, 2023 Share Posted August 17, 2023 The HP level determination is in the engine ECM. The rear gear ratio, tire size and various other parameters are stored in the VECU. I’ll do some looking on what you have Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-537193 Share on other sites More sharing options...
Rickvr Posted August 17, 2023 Share Posted August 17, 2023 2 hours ago, Mackpro said: The HP level determination is in the engine ECM. The rear gear ratio, tire size and various other parameters are stored in the VECU. I’ll do some looking on what you have Thanks! Meantime I disabled the limp mode by removing the mark on idle shutdown.... in V-macIII dealer programming. It runs awesome now :-) Except the error light is still on. I think and buy the M6 version of the vecu just to check. I can't see that there are many differences. And yes the vecu has nothing to do with HP etc. I'm so happy it works so I can work. Love my truck. (again :-)) 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-537210 Share on other sites More sharing options...
Mackpro Posted August 18, 2023 Share Posted August 18, 2023 If your original VECU was a 12MS48 M4 then a M5 or M6 will work. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-537296 Share on other sites More sharing options...
Rickvr Posted August 20, 2023 Share Posted August 20, 2023 On 8/18/2023 at 11:51 AM, Mackpro said: If your original VECU was a 12MS48 M4 then a M5 or M6 will work. Thanks :-) Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-537441 Share on other sites More sharing options...
Rickvr Posted September 21, 2023 Share Posted September 21, 2023 On 8/20/2023 at 11:18 AM, Rickvr said: Thanks :-) On 8/18/2023 at 11:51 AM, Mackpro said: If your original VECU was a 12MS48 M4 then a M5 or M6 will work. Finally I found a used VECU which is the M5. Yes it works however the 6-4 code is still there. Must be the wires even though I tested them. When I have time I will run new ones. If that doesn't work it must be the ecu maybe..? If that's the case I will leave it like it is. Quote Link to comment https://www.bigmacktrucks.com/topic/72632-electrical-problem-and-starting-problem/page/2/#findComment-539102 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.