Replaced IACV but the car still stalls

[scubawrstlr]

I Have had many problems with my car, '92 Cutlass Supreme 3.1, anyways. I can run it for about 20 miles and then the idle gets really rough and the car dies. So I searched online and found this place, and I read all about the idle air control vavle and possible vacumm leaks. I found one major leak...the mechanic didn't hook the vacumm line back up when he looked it over... So I hooked that back up. I replaced the IACV and I had the TPS tested which tested good. I think I may have another leak on a hose comming right out of the back of the manifold. I am going to fix that. Anyhow, I can run my car for about twice as long as I ever could before (now I can go maybe 20 miles at 55-60mph) before I have these problems. My dad keeps telling me to fix the cooling fan. The problem is that it doesn't always turn on and the car runs hot. I know there is a way to keep the fan running constantly or you can put in a switch to turn on the fan. Also, the "mechanic" that I went to told me that the reason my car is stalling is because the engine comtrol computer is going, I find this had to beilve now that I have read these forums. Any help would be great.

[Slade901]

Check your CTS (Coolant Temperature Sensor). If the CTS is bad, either it gives out a too cold signal or too hot signal to the computer.
If it is stuck in too hot, it signals the computer and in turn it will immediately close the fuel injectors and not stay long enough.
If it is stuck in too cold, it signals the computer and in turn it will immediately open the fuel injectors for a long time and probably flood the engine.
During initial startup (cold engine), the Normal CTS sends a cold signal to the computer to open the fuel injectors longer and then gradually returns the fuel injectors to normal operation as the temperature rises.


If your vehicle has a MAF Sensor then check it. The MAF (Mass Air Flow sensor usually located right after the air filter box) or ACT (Air Charge Temperature sensor usually located on the side of the air filter box). Try cleaning them with some throttle body cleaner and let it dry.

It could be your fuel pump relay failing. The fuel pump is also powered up by the oil pressure sender signal if the fuel pump relay is malfunctioning. Tell tale sign would be that you have to crank the engine a couple of times to get it started Or it fails when the temperature in the engine bay gets hotter and then the fuel pump relay malfunctions. Simple fix is to replace the fuel pump relay and if that does not fix the problem, it is something else.

It could be your Fuel Pressure Regulator failing. The Fuel Pressure Regulator has a diaphragm inside and if that diaphragm ruptures, excess fuel is sucked into the Fuel Pressure Regulator vacuum hose and into the intake. Check the Fuel Pressure Regulator vacuum hose for any sign of fuel inside the vacuum hose (do it after running the engine for a while).

On my 1990 Oldsmobile Cutlass, I rigged up and connected the two fans directly to the main fan and so both fan turns ON when the primary fan kicks in. It takes less time to cool the coolant.