My engine won't run

[Tinstar]

I need some help with a 1994 Allegro Bus. We're trying to start the engine and not having any luck. The engine cranks over fine but no start. It has not been started in several months. It has run fine for years prior to this problem.

Originally I could turn the key to the crank position and the engine would start and run AS LONG AS I HELD THE KEY IN THE CRANK POSITION (I did not let it run but a few seconds with the key in the crank position). As soon as I released the key to the run position the engine would immediately die. I believe that was due to a stuck fuel solenoid. My theory is; It would hold open while cranking but as soon as I released it to the run position, the fuel solenoid would disengage thereby shutting the fuel off and it would die. Anyway, I went underneath and messed with the fuel solenoid (exercising it checking the wires). I know it is holding in the run position BUT now it won't start (it does still crank). I am thinking I lost prime while it sat and I'm not getting fuel to the injectors. I've tried using the lift pump but still no start. I have pumped the lift pump dozens and dozens of times.

I am now thinking about cracking one of the banjo nuts at the injector and crank it over. I think I should get a fuel spray while cranking it over with a banjo nut loosened.

Before I go down that road, does anyone have any other suggestions and what do you think of my theory. Am I chasing the right solution???

[Blaster_Man]

Could have bad fuel or lost prime.

[gutfelt]

Tinstar wrote:

gutfelt wrote:
IF you had such a thing as a stuck fuel solenoid it would either be open or closed, it would not close when removing power if it was open when applying power if it did then its not stuck
IF the engine actually ran when holding in the crank position and dies when key released then you have a faulty ignition wire or switch system

From what I read, the fuel solenoid actually has two power wires going to it. One is a higher power to initially open the solenoid while the key is in the crank position and the other is lower powered to hold the solenoid open in the run position. I'm sure you're right about it not being stuck but what if the solenoid was not getting power after it cranked. The higher power wire gets power when cranking but when the key is released the lower power wire is supposed to take over holding it open. No power to that wire would allow it to close. Does that make sense???

that's exactly why I said its a failed switch or ignition wiring problem I doubt the power would be different from crank to run and vice versa both would be 12-13 volts
run a jumper wire to the fuel solenoid and see if it runs

[Tinstar]

gutfelt wrote:
IF you had such a thing as a stuck fuel solenoid it would either be open or closed, it would not close when removing power if it was open when applying power if it did then its not stuck
IF the engine actually ran when holding in the crank position and dies when key released then you have a faulty ignition wire or switch system

From what I read, the fuel solenoid actually has two power wires going to it. One is a higher power to initially open the solenoid while the key is in the crank position and the other is lower powered to hold the solenoid open in the run position. I'm sure you're right about it not being stuck but what if the solenoid was not getting power after it cranked. The higher power wire gets power when cranking but when the key is released the lower power wire is supposed to take over holding it open. No power to that wire would allow it to close. Does that make sense???

[Tinstar]

MountainAir05 wrote:
might help if you give the engine make and model

Sorry about that. It's a Cummins B5.9 (mechanical engine).

[gutfelt]

Tinstar wrote:
I need some help with a 1994 Allegro Bus. We're trying to start the engine and not having any luck. The engine cranks over fine but no start. It has not been started in several months. It has run fine for years prior to this problem.

Originally I could turn the key to the crank position and the engine would start and run AS LONG AS I HELD THE KEY IN THE CRANK POSITION (I did not let it run but a few seconds with the key in the crank position). As soon as I released the key to the run position the engine would immediately die. I believe that was due to a stuck fuel solenoid. My theory is; It would hold open while cranking but as soon as I released it to the run position, the fuel solenoid would disengage thereby shutting the fuel off and it would die. Anyway, I went underneath and messed with the fuel solenoid (exercising it checking the wires). I know it is holding in the run position BUT now it won't start (it does still crank). I am thinking I lost prime while it sat and I'm not getting fuel to the injectors. I've tried using the lift pump but still no start. I have pumped the lift pump dozens and dozens of times.

I am now thinking about cracking one of the banjo nuts at the injector and crank it over. I think I should get a fuel spray while cranking it over with a banjo nut loosened.

Before I go down that road, does anyone have any other suggestions and what do you think of my theory. Am I chasing the right solution???

IF you had such a thing as a stuck fuel solenoid it would either be open or closed, it would not close when removing power if it was open when applying power if it did then its not stuck
IF the engine actually ran when holding in the crank position and dies when key released then you have a faulty ignition wire or switch system

[MountainAir05]

might help if you give the engine make and model