05 coolant fan runs and now engine won't start

[SDE56]

We are in northern WI and it is cold here. Temp gauge reads low because the fan is running continuously. I disconnected the Temp. sensor and started the engine. The fan ran also. I plugged it back in. I took the cover off the fuse box that's by the battery. I saw in the cover that there is a 40 amp fuse -COOL HI (l-4)40 Amp. I pulled it, thinking that if the engine started and the fan does not run on high, then we might be able to get the engine temp to go up to normal. The engine didn't start. I put the fuse back in. It still didn't start. I drained the pressure off the fuel rail and tried to start it. No start but the fuel rail had pressure, so I think the fuel pump is ok. I disconnected the battery hoping that I just needed the system to reset to default setting. When I hook the battery up the fan starts and runs for a second or two. Then I saw the high and also the low speed relays for the fan. Oops. But I really hope that you can tell me what I messed up and how to fix my error so I can get it to start again.
TY
SDE

[SDE56]

Maybe it was flooded. I just got it started again, after it sat a while longer. I left the high speed relay out and I am going to hope that it will come up to normal temp.
Ty
SDE

[fdryer]

The engine coolant sensor is vital to the EFI system as it helps the ecm know when to richen fuel mixtures for cold startup, lets the ecm continually adjust fuel mixtures as coolant warms up, lets the ecm determine when coolant reaches around 225F to turn on the radiator fan, turn off when below 210F. Disconnecting the coolant sensor basically tells the ecm to do everything wrong; higher resistance from a cold coolant sensor is determined by the ecm to richen fuel mixtures. Disconnecting the sensor tells to ecm to flood the engine because the ecm thinks the engine is frozen well below actual outside temps. You inadvertently created a flooded engine with several starting attempts. The cooling fan running all the time may be simply a stuck cooling fan relay. You may have created several problems addressing a cooling fan problem when it should be off until needed.

The easiest way to address a cooling fan running issue in winter temps; disconnect either the fan relay in the fuse box or cooling fan wiring. In freezing temps, the cooling fan is hardly needed unless sitting in all day stop and go traffic with very little vehicle movement for cold air to flow thru the ac condenser and radiator.

Whenever a failed start occurs in winter temps, most if not all EFI systems automatically enrich fuel mixtures because of the coolant temperature sensor telling the ecm the engine's cold. Pre EFI when carburetors were de-riguer, stepping on the gas pedal once or twice pumped raw fuel into the intake while setting the choke plate closed. At startup, the extra fuel helped start a cold engine while the choke plate strangled the carburetor of air as fuel was sucked out the carb at a higher rate as the engine ran. A cam linkage also opened the throttle a little more for a high idle. After stepping on the gas pedal, the linkages dropped high idle down as the choke opened. Complicated old school carburetor fuel systems. EFI simply uses every sensor for the ecm to determine fuel and rpm settings. EFI systems uses zero linkages to a throttle body.

If several starting attempts fail, hold throttle wide open for the next start. The throttle position sensor tells the ecm wide open throttle lets the ecm shut off injector operation to allow 100% air intake without fuel for starting. As the engine cranks, excess fuel is blown out the exhaust, plugs dry while spark continues until ignition occurs to fire up the engine. As soon as the engine revs up, release pedal for normal warmup. EFI system don't need gas pedal pumping at any time since the ecm controls fuel mixtures, spark and injector pulses.

If you get the engine running again, reconnect the coolant sensor to allow the EFI system run the engine. Whether or not disconnecting fan wiring or relay temporarily stops fan running puts you back to the original problem.