So this is my first post on this forum and my first post on a Volvo Forum period. Recently I bought myself a 1993 Volvo 850 GLT N/A car after a short break i took from volvo ownership. The Volvo world isn’t new to me and the pricey maintenance schedule isnt either having previously owned an e46 drift car that loved to break every weekend. My previous volvos were a 2000 s60r which i very much regret selling and a 2011 c30 rdesign in the sunburnt orange which again i wish i still had.
Okay, done with my self welcome now into the fun troubleshoot ive done on my 850.
The issue: Car idles perfectly fine for about 1 minute then it stalls. This happens every single time. I can drive the car but after 1 minute it will inevitably stall.
The car does not hunt idle when it stalls. Does not lean out or cut the fuel pump. I opened up the relay and the solder joints were bad, i swapped in my buddies known good relay and the issue still occurred, the car stalls. Having seen the bad solder joints in my relay i replaced it anyway. I though maybe my pump had gone bad so i opened up the gas tank and pulled the pump out to find that it was the original pump so i replaced that too along with the original fuel filter. Bench tested my injectors and they were all good and replaced the seals. Issue still occurs the car will stall. I changed my ignition/injector relay and the issue still occurs car stalls. This has me thinking that something is commanding the ECU to shut off the car. I did lots and lots of research and found a fantastic write up about the ECT sensor that can send signal to the ECU to shut the car off if the coolant temp is too hot or there is loss of signal.
So i replaced the ect sensor and now my fan wont shut off. Before i put coolant in it i wanted to just test this in key position 2 and the fan starts and doesnt shut off. However they turn off when i shut the key off.
When i purchased this car there was a thermostat dial switch wired into the #2(High) fan speed centre connector on the fan control relay. He had the Temp set to 65C on the dial switch to turn the fan on. The dial read temperature from a probe that was shoved in the upper rad hose port on the radiator side.
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My Questions: Does this car have a failsafe where if the coolant level sensor reads lows it runs the fan and thats why my fan wont shut off while it has no coolant in it?
What are the odds the new ect sensor i put in is sending the wrong resistance and is a bad sensor and thats why the fans run constant. (the Ect is from Uro parts (im pretty sure the quality if their parts is poor but wanted to give the cheap sensor a shot))
Are there any other failsafes in the ecu that command the engine to shut off?
Sorry for the ramble i promise to keep the rest of my posts short and sweet.
My dad is a tv repair man, I can fix every piece of this car.
