It only starts when it has low temperature

Hi, I'm Raul. I have a problem and, above all, a big question. I have a 1999 Ford Focus 1.8 TDCi. About four months ago, I replaced the connecting rods because one broke. About a month ago, while driving, if I went over 3000 RPM, the glow plug warning light would come on and the car would stall, although it would restart immediately. I took it to the garage and they told me the problem was a part in the dashboard that they had to order from Ford, and I'm still waiting for it. The thing is, now the car starts perfectly fine from cold, and I can drive it normally. But if I turn off the engine and the temperature gauge is at least halfway down or a little below, it won't start. I have to wait until it cools down to the first bar on the temperature gauge before it starts perfectly again. I'd appreciate any help in knowing if anyone has experienced this and could clear things up for me, because the garage couldn't tell me exactly what the problem is either. But they say it could be the injection pump, and that's scared me quite a bit.
Regards and thanks.

Have they connected the computer? In some cases it's the crankshaft sensor or the valve that regulates the fuel in the injection pump.

I have an appointment at Ford tomorrow; they're going to do a diagnostic. I'll let you know what they say. The guy who helped me said it looks like it might be a sensor.
Thanks a lot.
Regards, Raul

Hi, something similar happened to me with a Toyota, gasoline engine, the problem was the engine temperature sensor, which always indicated to the ECU that the engine was cold.

Hi Raul, based on what you've said, it sounds like what our friend nizome suggested: a damaged or loose temperature sensor. Something similar happened to me with my Isuzu truck, and it turned out to be a faulty terminal on the temperature sensor (it uses two, one for the temperature gauge and another for the ECU, which was the one that was defective). Try pressing the accelerator almost all the way down when starting the engine while it's warm. Some ECUs detect this as "flooding" and don't inject extra fuel (like they would when the engine is cold). This is a temporary measure while you're fixing the sensor. Let us know how it goes. Good luck.