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Deere 770CH II starts and dies

Jarred4960 ยท 2023-05-03 12:27

Hi all, I have a 770CH II (PIN W770CH595386) (ESN:SE6081H390975) that will start and die. Machine fires up immediately and dies as soon as key is released. It will run if key is held in start position. It does read RPM when running and shows no codes. So far I have: Swapped around relays, checked fuses, changed out key switch with known good one, throttle position sensor swap with known good one, fuel filters new, tank screen is clean, connectors checked going to injector pump, multipin connectors checked between cab and engine bay. To the point of thinking its the injector pump or the controller, but I don't know which and there is too much money involved with those to just go firing the parts cannon. Any suggestions would be appreciated. Jarred

Replies10
  1. #1Welder Dave2023-05-04 22:40

    Does it shut off with the key? If so sounds like the fuel solenoid is not holding in the run position when you let off start position. I don't think it would keep running if the IP is bad. Bad wire, bad ground or wire connection if the fuel solenoid is OK. Maybe the fuel solenoid can be bypassed to see if it keeps running.

  2. #2mg23612023-05-05 05:49

    Key switch good? The ECU gets its switched power from a relay. That relay is controlled by the key switch. The switch provides power to that relay in both the crank and run positions. If the ECU does not have a switched signal, the engine won't run. So, I am guessing that when the key is released the ECU switched power goes away.

  3. #3dieseltoolz2023-05-06 02:48

    If there is no air there is no fire. Make sure the filters arent clogged up Had the same issue and ended up being an easy fix

  4. #4Jarred49602023-05-09 17:35

    That is difficult to say since it dies so quickly. Spoke with local pump shop and they say they that it sounds more like an electrical issue. Fuel shutoff was my 1st thought, as that is a common problem, but it is internal to the injector pump.

  5. #5Jarred49602023-05-09 17:38

    Yes I swapped out the key switch with a known good one and still the same problem. Local Deere sent me a diagnostic test sheet to confirm power to certain relays with key in different positions and it all checked out fine.

  6. #6Jarred49602023-05-09 17:40

    Fuel are new and air only has about 50hrs. on it since new, but it is clean.

  7. #7Welder Dave2023-05-09 23:17

    It definately sounds like an electrical issue. Can you check for power on the shut off solenoid with the key in start, run and off positions and do you know if power turns the fuel solenoid on or off? It sure sounds like it changes between start and run position. If it needs power run a temporary wire to it and see if it keeps running with the key in run position. If it doesn't need power disconnect the wire and it should stay running and not shut off.

  8. #8mg23612023-05-10 04:27

    Did you check for codes manually in the monitor rather than expecting a pop up?

  9. #9desertpirate2024-02-10 19:53

    Did you ever find the problem? I'm having the same issue

  10. #10Omar Simental2024-05-10 02:13

    Hi, im Heavy equipment mechanic just had the exact same problem took a couple of days to figure out the solution. It was the timing sensor near the front pully. We thought it was fine because we had rpm in the screen but found out alternator sent signal to the screen. Checked the sensor and a piece was missing changed it with a used one and fired right up, hope it helps.