TimberJack Posted March 4, 2023 Share Posted March 4, 2023 2008 chu mp8 starts an idles for about a min then dies. You can start it back up an go down road an then all of a sudden loses throttle pedal. When you pull off road an set brake truck will die. I can start it back up an it will normally run fine the rest of the day. This one is a new one on me. There’s no codes except fifth wheel solenoid. Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/ Share on other sites More sharing options...
TimberJack Posted March 6, 2023 Author Share Posted March 6, 2023 Now it want even idle for 3 mins then cut off. Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526622 Share on other sites More sharing options...
mrsmackpaul Posted March 6, 2023 Share Posted March 6, 2023 Sorry but this is to modern for to be of any help Paul Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526639 Share on other sites More sharing options...
TimberJack Posted March 6, 2023 Author Share Posted March 6, 2023 13 hours ago, mrsmackpaul said: Sorry but this is to modern for to be of any help Paul It’s driving me crazy! Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526649 Share on other sites More sharing options...
Adkat Posted March 6, 2023 Share Posted March 6, 2023 Sounds like you've got a fuel issue Have a hunt around on this site, there's loads of info on the MPs, especially for fuel issues. Will give you some ideas on where and what to check. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526651 Share on other sites More sharing options...
TimberJack Posted March 7, 2023 Author Share Posted March 7, 2023 Seems electrical bc when you lose throttle going down road you can kick it in neutral an it will idle just fine until you come to a complete stop. When it happens you don’t even have to turn switch off it will fire right back up an runs just fine until it does it again Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526687 Share on other sites More sharing options...
fjh Posted March 7, 2023 Share Posted March 7, 2023 1 hour ago, TimberJack said: Seems electrical bc when you lose throttle going down road you can kick it in neutral an it will idle just fine until you come to a complete stop. When it happens you don’t even have to turn switch off it will fire right back up an runs just fine until it does it again Bro I have read this over and over don't really get the jist! I was hoping some of the gurus here would pipe up So I will give it a stab! you mean the unit rolls to a stop but at an idle or it cranks the starter on its own to start up again after its stopped in neutral ? Sounds like a gremlin for sure! check EPDM panel for green fuses and breakers Is there a rubber boot around that fuse panel! its to the left of the clutch area there! this was an issue for awhile with most of these units!there was an TSB on the subject Mack pro Might shed some light on this! Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526689 Share on other sites More sharing options...
Mackpro Posted March 7, 2023 Share Posted March 7, 2023 Deleted? Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526690 Share on other sites More sharing options...
TimberJack Posted March 7, 2023 Author Share Posted March 7, 2023 1 hour ago, fjh said: Bro I have read this over and over don't really get the jist! I was hoping some of the gurus here would pipe up So I will give it a stab! you mean the unit rolls to a stop but at an idle or it cranks the starter on its own to start up again after its stopped in neutral ? Sounds like a gremlin for sure! check EPDM panel for green fuses and breakers Is there a rubber boot around that fuse panel! its to the left of the clutch area there! this was an issue for awhile with most of these units!there was an TSB on the subject Mack pro Might shed some light on this! When it does it going down road I knock it in neutral truck comes to idle it want shit off with key but once it rolls to a stop it shuts off. All the dash light stays on. It will start right back up an run fine for a few mins. Yes truck is deleted. I have 3 that’s been done from the same guy with zero problems. I can’t start truck at shop it will idle then shut down. It’s got me pulling my hair out. Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526694 Share on other sites More sharing options...
TimberJack Posted March 7, 2023 Author Share Posted March 7, 2023 Well I swapped ecm from one of my other trucks an it runs fine. Looks like I’ll be buying a new ecm. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526703 Share on other sites More sharing options...
Joey Mack Posted March 7, 2023 Share Posted March 7, 2023 That's good, that you figured it out.. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526704 Share on other sites More sharing options...
fjh Posted March 8, 2023 Share Posted March 8, 2023 9 hours ago, TimberJack said: Well I swapped ecm from one of my other trucks an it runs fine. Looks like I’ll be buying a new ecm. Yup good on you for taking the leap on that one!👍 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-526734 Share on other sites More sharing options...
FarmMech2022 Posted August 22, 2023 Share Posted August 22, 2023 On 3/7/2023 at 1:40 PM, TimberJack said: Well I swapped ecm from one of my other trucks an it runs fine. Looks like I’ll be buying a new ecm. Was this a permanent fix or did the problem come back? I have one that’s doing the exact same thing, but only after I used it to diagnose it’s twin… Quote Link to comment https://www.bigmacktrucks.com/topic/72567-mp8-idles-for-a-min-then-dies/#findComment-537568 Share on other sites More sharing options...
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