Hey everyone,

I'm having this problem where my 1990 740 Turbo will randomly turn off when going slow, usually when I'm making a turn on either a street or parking lot. I'm trying to find out specifically what it could be. I checked the fuel lines for cracks, the fuel pump and fuel filter underneath the car have also been replaced, I got a new fuel relay, and I've also installed new spark plugs, spark plug cords, distributor cap, and distributor rotor last night. I'm not sure what to do. The only thing I know for a fact that I'm picking up is the coil so that everything ignition-wise is new. I also pulled the [ 16 Heater blower, Air conditioning ] fuse because my A/C isn't working. I don't think that has anything to do with it, but I'd rather leave no stone unturned.

Appreciate it, everyone!

 

The engine has an idle motor/air control valve/many other names - It's function is to keep the idle speed constant. When they stick or go bad the idle speed can fluctuate or make the car stall.

The first think I would do is clean the throttle plate, set the throttle switch if needed, then check and adjust the basic idle. - Test the idle motor, and reset the throttle plate and switch if needed. Also a simple air leak in the intake system can cause stalling - any hose/part from the air mass meter to the throttle plate and the intake manifold gasket can cause an air leak. Common is the short hose on the intake side from the intercooler to the pipe gets a hole burned in the bottom of it. Or the expensive hose from the air mass meter to the turbo inlet.

Stalling while turning could be from wires touching/shorting out when the engine moves - does it do it always when you turn the same direction? Are there any codes stored in the self diagnostics? If your car has a speed sensor - What's it's condition? If it does not have a speed sensor you will have an impulse sender in the distributor - the plastic connector at the distributor breaks and shorts out sometimes. Or the impulse sender goes bad (sorry can't remember when Volvo went to speed sensors on the 740t)