Got a 744H that will crank no start. Operator says it started then just died. I think he ran it dry. Re fueled, purged all lines and still nothing. Dash gauge reads 18psi fuel pressure but will not start.
Welcome to HEF Byrdmech ! Serial number of the machine? Any codes? Press menu until d is in the monitor. Press select. You will be in the Fault code option. Press select again. If there are codes they will be here. Press next to scroll through the list of codes.
Thank you! Sn- DW744HX583295 The only code is low service brake pressure.
Those can be quite difficult to re-start after running out of fuel. On the back of the head, crammed up against the cab is the fuel pump and manifold. There is a short hose running between the two, clamp it off or remove and plug one end. This should help with starting.
Will try.
Post some pictures of the fuel supply/return lines as well as the filters.
It's been a long while since doing one and I don't have one to look at right now. Go to the Deere parts site, 744H, fuel transfer pump and manifold. You will see a short hose #18 I believe, plug that one.
Yes I have the diagram but this engine doesn't have that hose. Trying to post a pic but bad service.
Pics attached
Passenger side line going to front of head
That is the newer style fuel system. Sorry, I don't have an answer for you.
That is the single rail fuel system. There should be a diagnostic port behind the hand primer on the filter. We have an electric fuel pump setup to bleed the fuel system on those engines. The suction side (with 5/8" ID hose)of the pump goes to the diagnostic port (you need a JT03352 coupler). The outlet of the pump goes back to tank (1/2" ID hose). We run the fuel pump until there are no longer air bubbles present in the fuel. It takes about 15 minutes to bleed the air out of it.
Will try it out, thanks!
No joy. Sucked for a long while, still had bubbles but could be my pump cavitating. Also all pins have 0v at cannon plug at back of head with ko. Checked all fuses, good. Could the ecm have failed? No codes either.
Now I'm getting codes for cylinder 6,5,4,1 bad. 0436,0435,0434,0431.
With the connector disconnected to measure voltage, the ECU sees an issue and will not send any voltage to fire the injectors, and sets a code. Plus, you can't just measure voltage that way anyway for the injection circuit. Those are pulse width circuits which would require a scope to properly measure them. Those are all circuit open codes. Did those codes show up after your testing? If you ran out of fuel, I still think you have air in the system. Then try this, but be extremely careful. Remove the line from the back of the head at the filter end. Cap the line and the filter. Crank engine for a bit to see if it begins to start or starts. If it starts shut it down immediately. Next step needs to be taken with great care. Removing the cap from the hose. It will be under a lot of pressure so it needs to be loosened slowly to bleed off the pressure. Then connect the line and it should start.
I didn't remove the cannon plug, I traced it back to the ecm plug where I could fit the probe in the connector without removing it. The codes came up after cranking for a bit. Why would there be pressure at the filter end of the hose? That's the suction side. Right? I'll try it though. And I'm not positive they ran it out of fuel, the fuel gauge was inop. But the fueler said he only put 58 gallons in it. I think the tank is an 80 gallon. Yes I checked the pickup tube and repaired the fuel level sending unit. (Wires were broken).
An other bit safer way than capping and plugging the fuel line is to install a high pressure ball valve in-line.
If you backprobed and if you did not run out of fuel, then I would be checking for continuity in those wires from the ECU to the cannon plug at the head.