If anyone out there is on the fence about doing some upgrades on there 12.7 let me share you my experience. About 6 months or so back i contacted rebel127 that is on the boards here to have some computer work done on my ddec3 12.7 detroit. I sent rebel127 my ecm and he worked his magic and had it back to me in a couple days. My motor was set at 470hp from the factory and quite frankly was a turd, so thats where leon comes into play. I get the ecm back and install it into the truck and was a good noticeable difference from stock. But something wasnt right the truck would only make around 29psi of boost on a hard pull. So i did the obvious checks for boost leaks and found no change. I went online and ordered a bully dog exhaust manifold and had rebel send me a borg warner 171702 turbo and that helped but still wasnt where it should be. So after many months of talking with rebel127 and doing some internet reading we came to the conclusion my 5575 injectors were weak and not putting out enough fuel for everything to work right. Fast forward to about two weeks ago, I found a guy close to me (las vegas) and talked to him about a set of 5915 injectors. He set me up with a set for a very good price all flow matched and balanced. Now today i picked up the truck from my mechanic and walked out to talk to the tech who did the injector swap. As im walking up hes standing there shaking his head with a giant grin on his face. I said she runs that good huh, Hes like ooooo ya i think you will be happy with her now. So i fire her up and jump on the highway and all i can say is dang why didnt i do this sooner. The truck will pull the proper boost now and really get up and run and pull. I couldnt be any happier with how the truck runs now.
Also to note my motor is a 96 and pre egr ect....
Heres a list of things done to the truck
bully dog ceramic coated manifold
borg warner 171702 turbo
airdog champ II
12.7 detroit upgrades
Discussion in 'Trucks [ Eighteen Wheelers ]' started by prerunner404, Jun 21, 2016.
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Were your injectors old with lots miles on them or just not capable of flowing the fuel the ecm was asking for??
What exactly did the engine do when it wasn't running right? Did it stumble or skip or just fall flat after a certain pedal position
Just curious as I have a ddec 4 14L that seems to do weird things when the ecm is commanding a lot of pulse width .
Well motor had 100k on it when I put it in and I'm not sure what the status of the injectors put in were. I don't think they were capable of flowing what the ect was looking for fuel wise.
The truck always ran good but just was flat no power in 9/10 gear loaded and unloaded on hills. Would run fine on flat ground and do what I needed it to. The truck did have a stumble I'd say. Would almost act like it had a miss when pulling a hill when I was into the right pedal and I could feel a surge if I let the Rpms drop below 1400 rpm so I felt like I was always pushing the truck hard up hill to keep the rpm up.
From just the short bobtail ride today back to my garage today I could tell the truck had what felt like 100 plus more hp and flat out got up and ran. I could also tell the turbo spoiled much quicker as well. So that tells me the fuel is now there to spin the turbo like it should be spun. I litterly went from 5th gear getting onto the highway and ran all the way up to 10th gear and was doing 75 mph in like a 1/4 mile.
I'll know more tomorrow how it does when I hook back up to my trailer and really know come Thursday when I pick up my load.
But from what I've been told and read I have the right combo now with turbo tuning injectors and manifold. Only other thing I could do for more power is a 4912 cam ( I think that's the number) and that would be the extent of what my motor could take and still be reliable.
I'm beginning to think that's my problem with my truck . Runs great everywhere but if I ask for a lot , like the last 1/8th of the pedal it kinda noses over. Feels like it drops 50-60 hp and even sounds diffrent out the pipes. Back off the pedal and she comes back to normal.
I've done everything only thing it could be is injectors . I also have some weird surging going on at diffrent throttle positions.
I'm running Leon's tuning also and we can't put or finger on it.
Yup same boat I was in. Truck did same thing your talking about. With the 8" pipes I could hear the studder/hesitation in the motor when I asked the motor to give me her all. I don't think I'll have a issue now with that. I'd call Erich at sspd60 or Leon rebel127 on here. I have both there numbers if you need them. Just send me a pm. I got the same cam and injector info from both so I'd say I was given good info. I don't think either will steer you wrong.
Interesting . Your the first guy I've run across that seems to of had my same problem .
Thing is I always thought it was in the tuning or maybe fuel starvation to the injectors themselves.
I'm also running a airdog champ2.
Glad you got things sorted out. It's real frustrating when you know somethings not quite right but can't figure it out.
Ya I think I really noticed it once I did the tuning. I think the whole system has to be right for everything to work as it should, and not having the right injectors was the one thing off in my whole equation.
I think my ecm was calling for more fuel but my injectors couldn't deliver and were maxed out there for I got the stumble/miss/ect when I was really needing the truck to pull.
I was ready to pull the Detroit and put a 3406 cat in the truck. I'm glad I've stuck with it and figured it all out.swaan Thanks this.
Also to add I did new fuel lines and pump and that helped as well.
With stock tuning it will not do it .
I started to notice it a little bit when leon tuned my ecm with a 171702 turbo.
I then upgraded to a 80mm borg with the 1.58 housing so I had leon add more fuel then it really started to do it worse.
Surging and falling flat at anything over 80% throttle.
I'm actually running a tune from Erich now and it runs good with no surging but it also has way less power too.
I don't think I'm maxing out these injectors with his tune that's why it's running ok....
I'm going to have to talk to my injector builder in town and see what he says. Also I should find out what this engine has first off.
Thanks for the info
Any time Swann. With that 14.0l you should be able to get a good set of injectors and that motor should run hard. I just don't know what ones you would need since you have the bigger motor. Is yours a pre egr motor?
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