98 E7 350 no power

[Weston e7]

So I bought a 1998 Mac CH613 that came with an E7 350 ETEch . 
 

When I bought this truck, it would only boost 12 pounds of boost now I have checked everything as far as fuel pressure my timing sensor I have checked for boost leaks I have checked just about everything mechanically you can think of turbo injectors etc. so I went to the junkyard and got an ECM off a same model truck with the same engine put that ECM on my truck and a Truck started boosting 25 to 28 pounds of boost and I thought that my truck was fixed then after about the fourth or fifth test drive over a period of three days out of nowhere the ECM goes down to 12 psi. So my question is one am I missing do these Ecm need to be programmed? Why would it run good and then out of nowhere run bad 

Edited January 30 by Weston e7

[Joey Mack]

download the svc. bulletin for a 9-2 code and follow the procedures for cleaning the grounds..  I bet you have a bad ground, or even bad wires in the harness, which can be fixed if you find the damaged wire(s). 

[Weston e7]

1 minute ago, Joey Mack said:

download the svc. bulletin for a 9-2 code and follow the procedures for cleaning the grounds..  I bet you have a bad ground, or even bad wires in the harness, which can be fixed if you find the damaged wire(s). 

Any way you can find me a link 

[Joey Mack]

go to Mack E-Media website..  also, make up a foot long wire with medium sized alligator clips on each end, and clean a spot on the EECU and clip one end there, then clean a spot on the engine or a bolt, whatever, and clip the other end there.  then drive the truck..  if its runs good you can make a permanent ground wire..  

[Joey Mack]

9-2 code.pdf

[Weston e7]

7 minutes ago, Joey Mack said:

9-2 code.pdf 217.71 kB · 1 download

Let’s says it not a ground issue… do you know anything about programming problems? 

[Joey Mack]

can you post a good picture of your intake manifold?  as far as re-programming,  I dont know the history of the truck.  I always look at the simple things first.  these EECU's are pretty tough,  unless it was struck by lightning or in a major wreck, I would not look at the EECU.  

[Weston e7]

It only has an intake temp sensor . No boost sensor 

 

[Joey Mack]

ok,  its my bedtime, I expect others will add to this.  I will check back tomorrow

[fjh]

So what trans is behind this engine is it a Mack trans? Or fuller! There is a torque limit switch that could be at play here on a Mack  trans also ! If there is no check engine light on ! there is something holding back on the power the computer does not see! as joey mentioned grounds and battery / starter connections(top of list) places to start!  ! Note the check engine light will likely be on now due to a miss match code between VECU and The EECU at this point!

[Weston e7]

8 minutes ago, fjh said:

So what trans is behind this engine is it a Mack trans? Or fuller! There is a torque limit switch that could be at play here on a Mack  trans also ! If there is no check engine light on ! there is something holding back on the power the computer does not see! as joey mentioned grounds and battery / starter connections(top of list) places to start!  ! 

It’s a Spicer 10 speed

[fjh]

18 minutes ago, Weston e7 said:

It’s a Spicer 10 speed

I suggest you follow up on the first stuff posted by Joe there! Cheep and easy stuff first !  Also if you can poke around above the trans there and see if the are any wires that could be rubbed together  the torque limit switch is a 2 wire switch that may or may not be used on the Spicer trans! even if the switch is not there the wires likely are and  could be rubbed together ! Is the speedo working? ensure that there are no other switches at play!( Fifth wheel slide)( Air Ride Dumped) those type of switches! I don't recall if these were equipped with these safe guards or not BUT keep them out of the picture by having them turned off!  Note the torque limit will cut the power by 50%!

[Weston e7]

On 1/30/2024 at 10:48 AM, fjh said:

I suggest you follow up on the first stuff posted by Joe there! Cheep and easy stuff first !  Also if you can poke around above the trans there and see if the are any wires that could be rubbed together  the torque limit switch is a 2 wire switch that may or may not be used on the Spicer trans! even if the switch is not there the wires likely are and  could be rubbed together ! Is the speedo working? ensure that there are no other switches at play!( Fifth wheel slide)( Air Ride Dumped) those type of switches! I don't recall if these were equipped with these safe guards or not BUT keep them out of the picture by having them turned off!  Note the torque limit will cut the power by 50%!

Is there a torque limit on a 98 model 

[fjh]

11 hours ago, Weston e7 said:

Is there a torque limit on a 98 model 

If there are wires for the torque limit switch they will be towards the back of the trans likely tied back in the loom two wires! if it has a mack trans the switch is located on the back Cylinder At the top! Not sure if they use it on that trans how ever the the wiring will likly still be there ! I have NEVER seen a Spicer trans in that model not sayin it isn't possible usually Eaton fuller Or Mack! Spicer did clone a Fuller trans at one point so anything is possible!