05 engine in 04 Truck, Now "no Bus"

B

Bone stock 99

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I have an 04 1 ton dually with auto trans. I swapped an 05 engine into the truck and took out the banks six gun since it was the wrong year model. I put in 2 new optima batteries and have plenty of voltage to crank the engine over but with the 6 gun unhooked there was no signal to the gauges, all the gauge lights come on and the speedo and tach would rise and fall. No rpm reading while cranking and no voltage showing on gauges.

As a last ditch attempt to get it to fire i reinstalled the banks and now when the key is turned on, the odometer reads "no Bus", the speedo and tach do not move and i still get nothing out of the other gauges. The usual lights come on such as "4x4, Low Fuel, Check Engine, Etc" i went on an in depth check to see if i could find any loose wires. I even Rednecked up a ground with a pair of jumper cables and still nothing.

Anyone with info leading to getting this thing fired up I will pay lol. Your wallet and my hairline will thank you.:doh:
 
It sounds like you have a bad ground somewhere. If I was you I would go back and recheck all the grounds first. I am not sure how many there is but I know there will be more than one.
 
Well right now I have the 04 ecm hooked up but its hanging off to the side and not bolted to the engine, does it have to be solid mounted to the engine to make a ground or is the compute4 grounded some other way? I haven't tried hooking anything to the obd2 port yet either to see if it will read anything, cuz I doubt it will.
 
You've got to use the wire harness from the '04 as well. If it was a SO '04 you'll need to switch out the coolant temp sensor. No need to mount the ecm for testing but you will want it mounted for long term use.
 
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My 05 has a ground that comes off the ecm and bolts to the block...

That might have something to do with it..


It's the wires hanging off the block in this pic....



photo-27.jpg
 
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Ok I'm using my 04 harness and have it currently plugged into the 05 ecm which is solid mounted on the block. And as for your ecm ground swole, how is the broke side of your ground hooked to the ecm, lol theirs a bit missing in your pic. Is it spliced into not wiring or is it just bolted to the ecm? I checked for bad wiring and have found nothing. I have ground continuity from the engine to the frame, frame to the cab and battery terminal and every which way in-between. My guess is the harness I have isn't sending a signal from the ecm to the chases harness and from there to the gauges. I'm at a loss. Would pics of the mess help you guys help?
 
The ground wire is bolted to the ECM mounting plate that is what the ecm bolts to did you try the 04 ecm and the 04 wire loom together with it bolted to the engine
 
What other work have you done to the truck? Any Radio work? anything eles?

Or just the motor swap?
 
i dont have the 04 computer solid mounted and its had alot of electrical crap done to it before i removed the engine and i tried to not even mess with any of it. Mainly it looks like they did alot of trailer wiring and they wired in a fass pump and just little misc. stuff like that. i believe the problem lies either in the engine harness or the chasis harness. right now i have alot missing off of the engine such as fan, radiator, intercooler and things along those lines. Im gonna put the whole truck together and make a few last ditch attempts to figure it out before i take it to someone.
 
Due to security features the ECM must match the truck or it will never start
 
Im having similar problems blew up my 05 and put a 03 motor in it. used my 05 wiring harness and ecm. It starts fine, and will idle all day long. You can rev the motor everything sounds good but to drive the truck the first time you have to do anymore then completely baby it, like going up hill or just trying to accelerate any really the gauges quit working and truck shuts off. Then wont start back up until u pull the battery terminals..
 
Also mount the ecm when I first swapped motors my gauges wouldn't work and truck wouldn't start. I dunno about the 04 but like swole said the 05 has a ground wire with two eyes on it one goes on the top right corner bolt of the ecm the other goes to the mounting plate I think. I just doubled them up the first time on the ecm fixed that and fired right up. Now I have the above issue though..
 
WTF do you guys that swap engines do? You're only swapping an engine, not overhauling the electrical system! Either the problem was there before the engine got swapped or it got created while doing the swap. If it was there before the swap then the swap has nothing to do with it. If it got created, find it and fix it...it's probably a poor connection due to rust, paint, loose fasteners or bent plug pins.
 
Does it matter what year engine it is as long as the ecm matches the truck and wiring harness?

My ecm and wiring harness are original to the truck and still having an issue. The motor was out of an 03 but everything plugged in fine??
 
well i found my culprit but still havent got it running. i didnt have the red banks wire tapped into the pink and gray 14 pin connector on the firewall.
 
hey cummin get some, check all the bushings in the head that hold the fuel cross tubes in. if one of them is loose the truck will run for a while, then cut out and die, let it sit itll fire back up and do the same thing. you may even pull the cross tubes and check the o-rings out man ;)
 
Apparently, ECM/APPS compatibility is still a commonly overlooked engine swap issue - engine starts but has dead pedal... '05 saw the introduction of the new accelerator pedal TPS & ECM's zero-thottle launch feature.
 
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