Start for a second stalls

[Vicstruckservice]

I have a 1998 Mac RD with a e-tech e7 electric bosh fuel injection pump

 

 

(only on back half fuel pump). The truck starts runs for two seconds stalls, but starts right back up again no RPM gauge and the emergency shut off light stays lit changed the oil pressure sensor,changed coolant temperature sensor, and rpm sensor on flywheel also checked the wire harness connection on the fuel pump. I also checked all the fuses and relays and are good. we had a extra Bosch, few computer, swapped it out still the same thing, but there is another engine control module that we did not swap. Not sure if that could be the problem. Any help would be appreciative.

[JoeH]

You have oil pressure, but your engine shut down light is staying on. How's your coolant level? Also these may use 2 oil pressure sensors. One for the gauge, one for the EECU.  Will it continue to run if you hold down the shut down override switch?

Can you clarify which fuel system you have? Does this have 6 individual EUP's or one "traditional" style inline injection pump? If you aren't sure then post a picture of the passenger side of the engine, we can tell from that.

If it has a "traditional" injection pump then disconnect your shutdown lever on the pump from whatever electric solenoid controls it, put it in the "run" position and see if it'll run.

[JoeH]

It should run longer than that with low oil pressure or low water level. 

If it's the traditional injection pump then I'd suspect the shutdown lever solenoid. 

If it's an EUP engine then you can request Blink Codes by holding the Set/Decel cruise switch until the Engine Malfunction Light (lightning bolt) reacts and starts blinking a 2 digit code to you. Example, code 9-2 is engine shutdown without key.  Commonly caused by a loose EECU fuse, but basically means an interruption in EECU power circuit.

One code is spat out per request. So key on, engine off, hold Set/Decel. When it's done blinking hit it again for next code. Repeat until it starts blinking out the same sequence of codes again. Post any codes here and we'll look em up for you.

[JoeH]

Shutdown solenoid fault doesn't explain the constant shutdown warning lamp.  

[fjh]

On 2/2/2024 at 4:44 PM, JoeH said:

It should run longer than that with low oil pressure or low water level. 

If it's the traditional injection pump then I'd suspect the shutdown lever solenoid. 

If it's an EUP engine then you can request Blink Codes by holding the Set/Decel cruise switch until the Engine Malfunction Light (lightning bolt) reacts and starts blinking a 2 digit code to you. Example, code 9-2 is engine shutdown without key.  Commonly caused by a loose EECU fuse, but basically means an interruption in EECU power circuit.

One code is spat out per request. So key on, engine off, hold Set/Decel. When it's done blinking hit it again for next code. Repeat until it starts blinking out the same sequence of codes again. Post any codes here and we'll look em up for you.

Yup its not running long enough to even build O/P ! not an O/P or Low water issue! Do the check engine procedure as joe explains there!👍        60 seconds or so would indicate  a sensor ! Note I have seen stuck engine brake sols cause this on MP engines I know that  this is E7  how ever don't rule out anything! Also check the big round plug at the fuel pump un plug and replug it together several times it may have loose pins!

[Joey Mack]

Injection pump pin and plug inspection for sure..

[Vicstruckservice]

This motor does not have independent injection. It has the old style injection pump set up with only the rear connection for the throttle linkage is a wire pedal.. we changed the coolant temperature sensor and we checked for a second all pressure sensor, but it didn’t find one. It does have all pressure but as soon as it builds up all pressure it kills like I mentioned before. Also, the only electrical we have on the injection pump is, the pick up sensor on the side of it and the main harness that plugs into the rear of the injection pump they also is a three-way solenoid plug on front injection pump not sure where that is for. Does anyone know if they should be voltage to the fuel pump if so, what wire diagram will show you that . 

[fjh]

2 hours ago, Vicstruckservice said:

This motor does not have independent injection. It has the old style injection pump set up with only the rear connection for the throttle linkage is a wire pedal.. we changed the coolant temperature sensor and we checked for a second all pressure sensor, but it didn’t find one. It does have all pressure but as soon as it builds up all pressure it kills like I mentioned before. Also, the only electrical we have on the injection pump is, the pick up sensor on the side of it and the main harness that plugs into the rear of the injection pump they also is a three-way solenoid plug on front injection pump not sure where that is for. Does anyone know if they should be voltage to the fuel pump if so, what wire diagram will show you that . 

Did you try what Joe h posted ?

maybe you should?

[JoeH]

Sounds like you're working on a VMAC II system. Specifics are outside my wheelhouse.

It sounds like it shuts off as soon as you let go of the key.  My 12v Cummins uses a dual electric solenoid to stay in the "run" position. One strong solenoid pulls the kill lever into "Run", and a second solenoid holds it in "Run" while the first solenoid turns off.  Not sure what this Mack uses.

Other idea I have is faulty ignition switch.  Ignition power makes contact when you crank it, but as soon as you get off the crank position power drops out for whatever electronics the injection system needs to run.

I'd probably start with checking the ignition switch, then move to the shutoff solenoid.

[JoeH]

Read this thread.