mackrmodel686st Posted December 30, 2024 Share Posted December 30, 2024 I posted over a week ago and got no responses, so I'll try again. 2015 mack pinnacle with the mp7 engine. When the key is turned to the run position nothing happens, when turned to the start position the dash turns on like the key is in the run position. When you let off the key everything turns back off. Thought that maybe the key switch was bad so we replaced it but still have the same problem. Has anyone run into this problem and could someone possibly point me in a direction to start looking. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/ Share on other sites More sharing options...
fjh Posted December 30, 2024 Share Posted December 30, 2024 Sorry no one has posted ! as its not that common of a compliant ! Just stab in the dark ! I would try a new ignition switch! Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565027 Share on other sites More sharing options...
Joey Mack Posted December 30, 2024 Share Posted December 30, 2024 Sounds like the wires in the plug are switched around. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565028 Share on other sites More sharing options...
mackrmodel686st Posted December 30, 2024 Author Share Posted December 30, 2024 15 minutes ago, fjh said: Sorry no one has posted ! as its not that common of a compliant ! Just stab in the dark ! I would try a new ignition switch! We tried that already, problem still the same. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565030 Share on other sites More sharing options...
Joey Mack Posted December 30, 2024 Share Posted December 30, 2024 Is there a gray wire on the key switch plug? That would be the ground Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565032 Share on other sites More sharing options...
fjh Posted December 31, 2024 Share Posted December 31, 2024 somthing that has come to mind that you might try is to check the ecu plug for oil these had oil push issues in the wiring harness!! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565058 Share on other sites More sharing options...
mackrmodel686st Posted January 3 Author Share Posted January 3 On 12/31/2024 at 9:07 AM, fjh said: somthing that has come to mind that you might try is to check the ecu plug for oil these had oil push issues in the wiring harness!! We checked that for corrosion, didn't see any oil. I've seen on the older trucks with the vmac iii engines that the coolant level sensor will push coolant, but not oil. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565290 Share on other sites More sharing options...
Mackpro Posted January 4 Share Posted January 4 (edited) There is a ground stud welded to the frame rail behind the battery box. Check the wire from the ground stud to the negative on the battery. It’s a smaller fuseable link wire that can melt inside and cause this issue. I’ve also had the stud break loose from the frame and had the eyelet ends come looked from the cables Edited January 4 by Mackpro Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565363 Share on other sites More sharing options...
Mackpro Posted January 7 Share Posted January 7 I found my notes on this exact problem, “No power till you turn key to start position “. Fuse/breaker number 7 in top dash fuse box is bad or blown. The one I had used a fuse and showed 12 volts on both sides( key off) but when turn key to on position one side of the fuse dropped to 2 volts 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565675 Share on other sites More sharing options...
Popular Post fjh Posted January 7 Popular Post Share Posted January 7 39 minutes ago, Mackpro said: I found my notes on this exact problem, “No power till you turn key to start position “. Fuse/breaker number 7 in top dash fuse box is bad or blown. The one I had used a fuse and showed 12 volts on both sides( key off) but when turn key to on position one side of the fuse dropped to 2 volts Man / Mackpro you must have a Novel going by now! The shit that goes wrong with this stuff is endless! 🙄 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565679 Share on other sites More sharing options...
honkyshaq Posted March 16 Share Posted March 16 On 1/7/2025 at 9:07 AM, Mackpro said: I found my notes on this exact problem, “No power till you turn key to start position “. Fuse/breaker number 7 in top dash fuse box is bad or blown. The one I had used a fuse and showed 12 volts on both sides( key off) but when turn key to on position one side of the fuse dropped to 2 volts Thank God for you & this post. My son is transferring his moving business from California to Texas (for obvious reasons). However, it has not been an easy process getting his authority and such. So, it’s been parked for 3 months while he waits on the bureaucrats. To keep things moving & batteries up, I’ve been going over where it’s parked to start it and idle it up to build air and such and let it run for 30 minutes or so. On the fourth trip she started and died within about a minute. Cranked for a while but no start. Tried for an hour to get her running but no dice. Had a friend who works on Mack’s come over and try. He said it would start with ether but no go after a couple trips and tries. Son finally gets his IFTA and apportion plate and flies out to see if we can fix it. When we tried we ran into the problem mentioned in the quoted post. We would have never found the problem had it not been for “Mackpro” and his leading us to the fuse in the top of the dash THANK YOU!! Still cranks no fire, so we’re dealing with that but hope to figure it out soon. Now, at least it functions properly with the key and crank over. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571496 Share on other sites More sharing options...
Joey Mack Posted March 16 Share Posted March 16 Have you pumped the hand primer tol firm and then crank it? Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571500 Share on other sites More sharing options...
honkyshaq Posted March 16 Share Posted March 16 Yes…pump never gets real firm. Cranks no start even while pumping. Won’t even fire with ether. Sounds like it wants to light but doesn’t. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571508 Share on other sites More sharing options...
Joey Mack Posted March 16 Share Posted March 16 Im not a fan of ether on a diesel, especially MP's. If you spray in the filter it wont get to the engine untill the CAC has a bunch of it laying inside, then when it does light, it will run away. I have seen that a few times.. if you insist on ether, pull a plug out if the intake or loosen the boot on the intake and sneak it in.. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571512 Share on other sites More sharing options...
honkyshaq Posted March 16 Share Posted March 16 I’m with you on the ether. We’re gonna figure this out at some point. Appreciate the engagement. 😉 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571513 Share on other sites More sharing options...
Joey Mack Posted March 16 Share Posted March 16 I understand, I am from the real world of getting thing done, or running, and have done things that arent to be done often.. are you familiar with the injector cup issues in the MP's? You can hook the clear line to the front of the head on the regulator and run it back to the tank to see if it has a lot of air in the system. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571514 Share on other sites More sharing options...
honkyshaq Posted March 16 Share Posted March 16 We’ve seen posts on that topic. Honestly, my thoughts are if we are spraying ether directly into the turbo, and it’s not firing off…at all, there’s another issue other than fuel. Maybe not enough compression. ??? Funny this all started abruptly after a few start n run sessions to keep batteries up and critters out. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571515 Share on other sites More sharing options...
Joey Mack Posted March 16 Share Posted March 16 Into the turbo is just going to fill the CAC... Go direct into the intake.. ot will take a lot less. A 1 second squirt.. also, keep in mind, if you have the pre heater at the front of the intake, you may just have a kaboom... Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571516 Share on other sites More sharing options...
honkyshaq Posted March 17 Share Posted March 17 Thank you. Will give that a try. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571528 Share on other sites More sharing options...
fjh Posted March 17 Share Posted March 17 15 hours ago, honkyshaq said: We’ve seen posts on that topic. Honestly, my thoughts are if we are spraying ether directly into the turbo, and it’s not firing off…at all, there’s another issue other than fuel. Maybe not enough compression. ??? Funny this all started abruptly after a few start n run sessions to keep batteries up and critters out. I highly doubt a compression problem my self chances are its injector cups! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571534 Share on other sites More sharing options...
honkyshaq Posted March 17 Share Posted March 17 I’m leaning that way as well. With all the reading I’ve been doing, seems the cups/injectors are problematic on the MP8. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571540 Share on other sites More sharing options...
Popular Post honkyshaq Posted March 22 Popular Post Share Posted March 22 For any that may be interested, turned out to be a bad turbocharger. She just couldn’t breathe. Took the turbo loose; enough to achieve a gap between the exhaust manifold & turbo, and she started. Installed turbo kit; good as new. Thanks for all the engagement. 3 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-571794 Share on other sites More sharing options...
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