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MX13 Parts Engine

Jun 21, 2024 at 08:40 AM CST
+ 5 - 1
Not sure if the forum is the place for this or not but does anyone have any experience with an EPA10 MX13 main engine wiring harness going bad? It’s in a ‘12 T800 and injectors 3,5,&6 are not firing. We’ve replaced the injector wiring harnesses (the top plug on the ecm) and put a used main engine to cab wiring harness (the middle plug on the ecm) on it but now the shop thinks maybe that harness is also bad. We’ve ruled out the injectors because we swapped them with the other three and our problem stayed in the same holes. The used harness I put on looked very good condition, I just can hardly believe that we don’t have another problem somewhere else. Just don’t want to throw a 2000 dollar harness on just to see if it fixes it. The shops at there wits end on it and so am I. Any ideas?
Replied on Fri, Jun 21, 2024 at 01:41 PM CST
- 1
Injector drivers in the ecm going out? If you have access to another ecm try swapping it and see what happens.
Replied on Fri, Jun 21, 2024 at 01:53 PM CST
Quote: "Injector drivers in the ecm going out? If you have access to another ecm try swapping it and see what happens."

Yea we did that already. No difference….
Replied on Tue, Jun 25, 2024 at 08:48 AM CST
+ 1
Quote: "Injector drivers in the ecm going out? If you have access to another ecm try swapping it and see what happens."

We had one of those engines come in on the hook Driver says it shut down on the road.He jumped wired a spot in the wiring harnesse to get it to run and shut off again ,so we look at it it says bad wiring harnesses we replaced it checking it it say next section bad ,we ordered it then no voltage we check harnesses it's self they left out 2 main wires in harnesses that make the engine talk to the truck, there are 1000sof bad harnesses made in Mexico, so paccar says we will pay to figure it we did and now they don't pay so in the mean time when the jumper wire got put in it burns out the board everything new 4 months later customer it hot but understands the issue. Truck is for sale

Replied on Tue, Jun 25, 2024 at 09:20 PM CST
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Quote: "We had one of those engines come in on the hook Driver says it shut down on the road.He jumped wired a spot in the wiring harnesse to get it to run and shut off again ,so we look at it it says bad wiring harnesses we replaced it checking it it say next section bad ,we ordered it then no voltage we check harnesses it's self they left out 2 main wires in harnesses that make the engine talk to the truck, there are 1000sof bad harnesses made in Mexico, so paccar says we will pay to figure it we did and now they don't pay so in the mean time when the jumper wire got put in it burns out the board everything new 4 months later customer it hot but understands the issue. Truck is for sale"

I wouldn’t recommend cutting and spicing wire harness’s on today’s vehicles, since many of them are transmitting Data through a Canbus network, it’s not just DC voltage anymore, but after he mentioned they tried a different ECM already without any success, it definitely points back towards a harness issue. The maintenance costs of today’s trucks is far greater since they are now giant computers on wheels, you need to be part mechanic, part computer programmer, part electrical engineer to troubleshoot this new stuff, it’s easy to see why nobody wants to be a service tech these days, I miss the days of a mechanical diesel, 3406, NTC, 8V71, totally EMP proof too.
Replied on Wed, Jun 26, 2024 at 07:36 AM CST
+ 1

if a damn truck aint worth a few thousand dollar fix..junk it...the truck itself is probly a real piece a junk besides..dont quite understand people bitch about a few bucks to fix the problem..fix it..get to work

Replied on Tue, Jul 02, 2024 at 07:51 AM CST
Well. Mx13 harness go bad all time. Very common. When i was in kw sitting in lounge, at keast 4 trucks came in for that including mine . EPA 13. But same crap. 13k fir engine and aftertreatment harness. Best thing to do is have a mechanic overlay it. A few hundred bucks for overlay. But that harness is about 14 hours if work to R&R. I should have towed my truck home and had my mechanic fix the bad wires in it.
Replied on Tue, Jul 02, 2024 at 11:13 AM CST
Well we’ve diagnosed about every wire on that truck at this point. And tried swapping out harnesses off of other running trucks, swapped ecms, ran all kinds of tests and the shop is at a dead end street on it. Shout out to Diesel Solutions in Seminole TX. I guarantee those guys spent 60 or 70 hrs on it they are only charging me 255 bucks for the initial hookup fee because they said if they can’t fix it they aren’t gonna charge for it. Good guys. They definitely got my business. Currently looking for a C15 to repower the truck.
Replied on Tue, Jul 02, 2024 at 11:52 AM CST

Any corrosion or blockages in the fuel system that would block fuel to those injectors?

Replied on Tue, Jul 02, 2024 at 01:25 PM CST
We’ve tested all the pressures in the fuel galleries and everything is nominal. Even tried a new lift pump on it.
Replied on Wed, Jul 03, 2024 at 07:28 AM CST
- 1
I would perform a leak down test to determine if you have a valvetrain issue being misdiagnosed as Something else.
Replied on Fri, Jul 05, 2024 at 07:38 AM CST
Shop said they did a leak down test and it all tested out good. 🤷🏼‍♂️
Replied on Fri, Jul 05, 2024 at 08:27 AM CST
Worked on 1 truck wouldn't start computer states it's wiring harnesse voltage is weak, batteries are good so we found center section of harnesses bad, y I don't know low voltage hmm, so we replaced then went on to make sure all is good no it says still a problem we replaced main harness that the computer talks to engine to truck ,computer say replace we ordered 1 came in 2 main wires missing in new harness made in Mexico, kenworth and manufacturers say fine problem we will pay you sa we did now they won't pay after 3 days to find, so everything is new now so while testing it say the main board is out when we checked the first time and says it's good everything plus the board is new now it runs after siting 4 months waiting on parts that are junk , have a blessed day
Replied on Tue, Aug 20, 2024 at 02:50 PM CST
To get the details on this engine you can read the previous forum posts on this string. Parts for Sale! Currently repowering the truck and have lots of paccar parts for sale. Complete engine along with all the accessories, wiring, turbo, air compressor, clutch, 10 speed transmission, etc,. Ecm is new in November of last year and is tuned and d?l?t?d up to 525. We did confirm that the ecm is good by putting it on another truck. Will back the ecm with a 3 month money back guarantee. Text or call me for details. 806-292-9530.
Replied on Wed, Aug 21, 2024 at 08:32 AM CST
- 1
Quote: "To get the details on this engine you can read the previous forum posts on this string. Parts for Sale! Currently repowering the truck and have lots of paccar parts for sale. Complete engine along with all the accessories, wiring, turbo, air compressor, clutch, 10 speed transmission, etc,. Ecm is new in November of last year and is tuned and d?l?t?d up to 525. We did confirm that the ecm is good by putting it on another truck. Will back the ecm with a 3 month money back guarantee. Text or call me for details. 806-292-9530."

The delete is what caused the problem, there are multiple other computers connected to the ecm via the Canbus network, they all need to be sync’d to the ecm, once it figures out it’s been deleted it releases a worm into the network, but James Bond could fix it.
Replied on Thu, Aug 22, 2024 at 07:37 AM CST
Negative. Tried new undeleted ecm and it made no difference.
Replied on Thu, Aug 22, 2024 at 09:35 AM CST
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Quote: "Negative. Tried new undeleted ecm and it made no difference."

The ecm is dependent on data or signals from other components, if those systems are corrupted the the ecm can’t do its job, just like a ecm on a old 3406e can’t function if the timing sensor is bad, it’s the simplest way to explain it but not the best example because we are comparing analog to digital, you can’t compare a delete on a Paccar to that of a older caterpillar, because it’s a different animal, I can guarantee that Paccar could fix it, however it would have to be converted back to factory specs, Bodyshops for example now have to reprogram the ECU on a car if they change a door out, otherwise the electric windows and locks won’t work, even though it’s a factory part.
Replied on Thu, Aug 22, 2024 at 10:50 AM CST
Quote: "The ecm is dependent on data or signals from other components, if those systems are corrupted the the ecm can’t do its job, just like a ecm on a old 3406e can’t function if the timing sensor is bad, it’s the simplest way to explain it but not the best example because we are comparing analog to digital, you can’t compare a delete on a Paccar to that of a older caterpillar, because it’s a different animal, I can guarantee that Paccar could fix it, however it would have to be converted back to factory specs, Bodyshops for example now have to reprogram the ECU on a car if they change a door out, otherwise the electric windows and locks won’t work, even though it’s a factory part."

Not to be contrary but if that’s true then how do you explain the literally thousands of paccar engines that are deleted and running for years like that? This truck ran for years deleted and then the ecm blew so we had to get a new one and redelete it. Ran fine for 4 months after that till it started acting up. Also the paccar techs at Peterbuilt had a chance on it and they couldn’t figure it out. They had the latest Davies software and it wouldnt show anything up even with that. Idk, not saying that I know your wrong, I just have a hard time believing that given the extensive troubleshooting and diagnostics we did. Especially so since even Paccar couldn’t get it. But hey we coulda missed something.
Replied on Fri, Aug 23, 2024 at 07:50 AM CST
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Quote: "Not to be contrary but if that’s true then how do you explain the literally thousands of paccar engines that are deleted and running for years like that? This truck ran for years deleted and then the ecm blew so we had to get a new one and redelete it. Ran fine for 4 months after that till it started acting up. Also the paccar techs at Peterbuilt had a chance on it and they couldn’t figure it out. They had the latest Davies software and it wouldnt show anything up even with that. Idk, not saying that I know your wrong, I just have a hard time believing that given the extensive troubleshooting and diagnostics we did. Especially so since even Paccar couldn’t get it. But hey we coulda missed something."

Was the truck in stock form when Paccar looked at it? Or did it have a delete file installed at that time? This is a critical detail.
Replied on Sun, Aug 25, 2024 at 10:50 AM CST
Quote: "Was the truck in stock form when Paccar looked at it? Or did it have a delete file installed at that time? This is a critical detail."

It had a delete file at the time. We didn’t take the truck to their shop because they wouldn’t work on it without wiping the file off per protocol or something I guess. But because the shop I had it at was close friends with the techs from Peterbuilt they were able to get them to help trouble shoot it and they finally said that they wouldn’t know what else to try even if it was at there shop. Specially because the shop that the truck was at was using the same software that the Peterbuilt techs would have used if it had been there.
Replied on Sun, Aug 25, 2024 at 03:05 PM CST
- 1
Quote: "It had a delete file at the time. We didn’t take the truck to their shop because they wouldn’t work on it without wiping the file off per protocol or something I guess. But because the shop I had it at was close friends with the techs from Peterbuilt they were able to get them to help trouble shoot it and they finally said that they wouldn’t know what else to try even if it was at there shop. Specially because the shop that the truck was at was using the same software that the Peterbuilt techs would have used if it had been there."

Software designed for a stock engine cannot read a custom file, the best way to find the problem is to put it back to stock, otherwise you have to just keep replacing parts till you get there, Something is telling your ECM not to fire those same three cylinders, I would be wondering what gives it the signal? Or alters it? I.e emissions system module?
Replied on Mon, Aug 26, 2024 at 09:06 PM CST
Quote: "Software designed for a stock engine cannot read a custom file, the best way to find the problem is to put it back to stock, otherwise you have to just keep replacing parts till you get there, Something is telling your ECM not to fire those same three cylinders, I would be wondering what gives it the signal? Or alters it? I.e emissions system module?"

Could be. I suppose I’ll never know what it for sure is, which really actually bugs me. But it is what it is. For now I’ll guess it’ll get used as a boat anchor.