jimmycarter Posted January 21, 2018 Share Posted January 21, 2018 ENGINE WILL NOT TURN OVER WITH THE KEY SWITCH NO POWER AT THE STARTER. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/ Share on other sites More sharing options...
turckster Posted January 22, 2018 Share Posted January 22, 2018 Many things could cause this issue from blown fuse to bad ignition switch, bad vehicle ecu or engine ecu. You need to check all fuses- ones under center dash panel and inside left side kick panel. Check voltage at starter relay w/key in start position, should be 12+ volts. If less than or nothing check ignition switch, I have seen the crimped connectors on the back of the switch be loose causing a bad connection. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-390282 Share on other sites More sharing options...
OJ Avery Posted January 23, 2018 Share Posted January 23, 2018 We have an over heat solenoid on our mp7's, idk if it comes on all. We've seen a no start condition caused by this Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-390360 Share on other sites More sharing options...
turckster Posted January 25, 2018 Share Posted January 25, 2018 On 1/23/2018 at 5:59 AM, OJ Avery said: We have an over heat solenoid on our mp7's, idk if it comes on all. We've seen a no start condition caused by this All Mack mp engine starters are controlled by the engine ecu. The eecu provides the ground circuit for the starter relay. The purpose for that is to protect the starter from overcranking/overheating. If the eecu sees excessive crank time it shuts off the ground circuit to the starter relay for a minimum of 30 seconds. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-390466 Share on other sites More sharing options...
TimberJack Posted January 28, 2018 Share Posted January 28, 2018 (edited) Mine did the same thing. Took it to Mack and they pulled the oil temp plug on the driver side of oil pan and cleaned the oil out of it an it started right up. They told me it was a ground problem from the oil and said I need a new oil temp sensor. They told me the grounds has something to do with the ECM to the starter. Sounds crazy but it fixed my problem. Wished I would’ve knew that before I replaced key switch, starter relay and starter. Edited January 28, 2018 by TimberJack Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-390690 Share on other sites More sharing options...
jimmycarter Posted February 7, 2018 Author Share Posted February 7, 2018 checked the plug on pan had oil on it cleaned it still no crank. switched out engine ecm still no crank switched out cab ecu still no crank can use some help. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-391418 Share on other sites More sharing options...
TimberJack Posted February 8, 2018 Share Posted February 8, 2018 Can you start the truck by jumping it on the starter? Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-391453 Share on other sites More sharing options...
jimmycarter Posted February 8, 2018 Author Share Posted February 8, 2018 I can use a bump switch to spin the engine over but the truck will not start. no power at wires to starter from the key switch. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-391478 Share on other sites More sharing options...
bbigrig Posted February 18, 2018 Share Posted February 18, 2018 (edited) 10amp ignition fuse in center dash panel. F7 I think..... Ive seen these fuses blow when the polarity at the mag solenoid on the starter is reversed by mistake or the solenoid is fried. Your dash will light up etc but on key turns the starter won't engage. Check the ign fuse. These trucks usually don't use the starter over heat switch supplied on the starter but as said earlier, time out by ecm. If it won't engage at all this may be your issue. This simple issue surprised the heck out of me and only found it through using the Mack/Volvo online wiring diagrams. Stumbled on this issue after new starter was installed by customer. Let me know if that helps. Edited February 18, 2018 by bbigrig Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-392355 Share on other sites More sharing options...
j_martell Posted February 18, 2018 Share Posted February 18, 2018 my old MP7 granite did the same thing years ago, had it towed back to Cambridge from Halton Hills, all because some 14 gauge "trigger wire" rubbed through on the trans. Quote Lack of planning on your part does not constitute an emergency on my part.... Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-392358 Share on other sites More sharing options...
George h Posted January 30, 2019 Share Posted January 30, 2019 I have a 2009 Mack with a mp-8 . You turn on the key and crank the starter will engaged for about a second or less then it shuts off you can cycle the key and it will do it again it has a new wire harness new starter all the fuses and relays have been replaced the dealership is worked on this problem 4 different times and have not fixed it my question is it possible that the engine ecm is bad or the eecm I don't want to replace the wrong one Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-414465 Share on other sites More sharing options...
turckster Posted January 31, 2019 Share Posted January 31, 2019 11 hours ago, George h said: I have a 2009 Mack with a mp-8 . You turn on the key and crank the starter will engaged for about a second or less then it shuts off you can cycle the key and it will do it again it has a new wire harness new starter all the fuses and relays have been replaced the dealership is worked on this problem 4 different times and have not fixed it my question is it possible that the engine ecm is bad or the eecm I don't want to replace the wrong one Sounds like the cam position and crank position sensor connectors are crossed. The ecu see's excessive speed and shuts off the starter. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-414540 Share on other sites More sharing options...
George h Posted January 31, 2019 Share Posted January 31, 2019 Thank you I will CK that and let you know if it works. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-414558 Share on other sites More sharing options...
shawnparks Posted September 21, 2019 Share Posted September 21, 2019 I have an 09 Mack with an MP-8 also. Has anyone ever gotten the message 'operation failed' when checking for diagnostic codes? Whenever I have checked for DTC codes in the past, if any were present, they have always came up with the proper code numbers. I left the truck idling to load a machine on the trailer and got ready to leave and noticed the truck had shut down. All of the electronics and A/C were still on but the engine had shut down and no alarms. This truck does not do that like the newer ones do. Turned the ignition switch off and back on to fire the truck back up, but the starter will not turn over. The relay under the CB is clicking, the batteries have proper voltage and proper voltage at the starter but will not engage. After this happened, I checked the DTC's and when I go to the 128 Engine code section the 'operation failed' keeps coming up. The ABS, Cluster and VECU all come up with codes which all show up to be a J1939 data link connector. The dealer says that this is the entire wiring harness. My suspicion is the ECU has gone haywire since the engine code shows 'operation failed'. Has anyone had this pop up on their codes? Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-432582 Share on other sites More sharing options...
Mackpro Posted September 22, 2019 Share Posted September 22, 2019 Usually it’s the engine ECM has died . See if you can read the engine hours in the display under trip data . If just dashes shows up and no numbers then there’s a good chance the ECM is fried. Hopefully is just a fuse though but be prepared for a ECM 1 Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-432653 Share on other sites More sharing options...
shawnparks Posted September 22, 2019 Share Posted September 22, 2019 Brother, you hit the nail on the head!! Just checked the hour meter and nothing but dashes. All of the fuses in that lower left box check good for continuity. I have been suspicious of the ecm going haywire for a couple of years now, but everyone says not likely. I had a brief spell on a trip a couple of years ago that the truck acted strange on the interstate and the lightning bolt and other lights came on. By the time I got off the interstate and checked under the hood, the lights were out when I got back in the truck. The truck has never had the same power since that incident and occasionally still flashes those warning lights briefly, but never stay on long enough to get it checked. The best that I can remember, the hour meter was showing around 5 or 6 thousand hours prior to the original incident. Ever since then, the hour meter jumped to 9,999 and has stayed there ever since. THANK YOU for your help!! Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-432689 Share on other sites More sharing options...
shawnparks Posted September 29, 2019 Share Posted September 29, 2019 Can't win this one. Put a new ECM on the truck and the 4 DTC codes that were showing went away and the engine hour meter is back to reading correctly, but the truck still won't crank. It now has a code on the VECU saying that there is a grounded or broken wire. Anybody have any suggestions?? Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-433043 Share on other sites More sharing options...
Ishola Posted October 11, 2019 Share Posted October 11, 2019 I have mack 2009 mp8. It not starting. I change the starter and it start, but after about 5mins, it goes off and didn't start again. Since then I have been pushing it to start, but just rolling. When I just start it with 12+ from the battery it starting. But I tried to use the negating wire on the tyre reem and the positive on the battery it roll better. But still didn't start Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-433713 Share on other sites More sharing options...
Duranbrothers Posted March 13, 2020 Share Posted March 13, 2020 Shawnparks did your coolant temp, exhaust temp, and oil temp also have dashes? My hour meter was stuck on 9999 when I bought my truck and I thought nothing of it, had a lot of power and ran it for 60k miles. Then at the pit I’m waiting to get loaded and bam just turned off. And won’t crank, just heard relays click. I really don’t want to change ecm. Called dealership and they said I probably have a short to ground in the wire harness somewhere. Did you find your short? Or change the main harness? I need help bad I can’t afford a 3k ecm Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-445232 Share on other sites More sharing options...
Dee. Posted March 22, 2020 Share Posted March 22, 2020 On 2/7/2018 at 8:05 PM, TimberJack said: Can you start the truck by jumping it on the starter? I hope you already solved your problem but you definitely can that’s how we got ours going first then replaced some wires and can do it off the silinoid in the junction box still trying to get cab power at all and start from key Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-446310 Share on other sites More sharing options...
Eddie1 Posted October 3, 2020 Share Posted October 3, 2020 2015 mack shuts down. Will not turn over . Wait 45 minutes.and it restarts. Sometimes a bump will cause it to shut down. Losing money and replacing parts.!!!!???? Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-461805 Share on other sites More sharing options...
Dailybread Posted March 13, 2021 Share Posted March 13, 2021 On 2/7/2018 at 8:05 PM, TimberJack said: Can you start the truck by jumping it on the starter? I have the same problem. I can jump mine at the starter. I have power in my Allison shift pad and no ignition. If I get ignition it cuts out real fast. Help please Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-470567 Share on other sites More sharing options...
Kbt mud carter Posted March 14, 2021 Share Posted March 14, 2021 There’s a big 100amp or 150 amp fuse in the battery box in a plastic cover. Check that first Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-470617 Share on other sites More sharing options...
fjh Posted March 15, 2021 Share Posted March 15, 2021 (edited) We ran into one the other day where by the little relay failed and was replaced but installed back wards still wouldn't start (Wrong polarity) swapped the wires and it started think this was mentioned earlier how ever worth saying it again! Its polarity sensitive! Edited March 15, 2021 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-470741 Share on other sites More sharing options...
MarcoPolo21498 Posted August 16, 2021 Share Posted August 16, 2021 Engine will not turn there is power going to starter. Also power to lights when key is on position. When key is turned to the ignition position there is power in cab for 5 seconds then shuts off, engine will still not turn. Quote Link to comment https://www.bigmacktrucks.com/topic/52270-mp8-engine-no-crank-with-key-switch/#findComment-478448 Share on other sites More sharing options...
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