1996 Olds Cutlass Supreme 3.1 trouble starting???

[MeanWS6]

My 1996 Olds Cutlass Supreme 3.1 has been trouble free for the last 80K miles (currently 120K).
Just did a complete tune up on her, because I was getting random misfire codes and hard starts. I replaced injectors, plugs, wires, coil packs, ignition control module, crank sensor and PCM in my quest to clear up the misfire. But I am still having problems starting it.

It only happens after it sits for awhile. I have to hit the accelerator while starting to get it to start. It turns over fine also.
I have turned the key to “on” to prime the fuel lines, etc, but still same issue

Any thoughts guys? Could it be a fuel pressure regulator?

[Slade901]

Three things I want you to check.

1. Take out your IAC (Idle Air Control solenoid) which is located on the throttle body. Clean it with a throttle body cleaner and a brush. Clean the spot where the IAC goes in to the throttle body.
If that does not work you may have to replace the IAC $29.

2. The TPS (Throttle Position Sensor) also causes problem which is located below the IAC. The TPS at IDLE provides voltage value to the computer and that's what how computer determine the position of the throttle plate. If there is a dead spot on the TPS providing incorrect voltage then it will throw the computer a little bit. The TPS can't be cleaned and you just have to replace it $19.

3. 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.

Check the connectors as well of all sensors.

[MeanWS6]

Slade - thanks for the direction, will give your troubleshooting steps a try this weekend and get back to ya

Would I normally get an MIL/SES light for these though?

thanks a million!!!!
I was losing my damn mind with this thing.

[jlimrick]

I've been having the same problem with my 96 Cutlass Supreme. I've replaced the IAC and the TPS, cleaned the MAF and ACT. These things only helped a very small bit and I can notice that small bit, but it still has the problem. It starts fine in the morning, and even if you shut it off after driving then restarting within acouple minutes. Any longer than a couple minutes you either have to try a couple of times or put the pedal down when starting. Any other ideas? I was kind of thinking that the fuel preasure regulator might need changed or even a new fuel filter. Please let me know.

Thanks!
Jeff

[Slade901]

Originally Posted by jlimrick

I've been having the same problem with my 96 Cutlass Supreme. I've replaced the IAC and the TPS, cleaned the MAF and ACT. These things only helped a very small bit and I can notice that small bit, but it still has the problem. It starts fine in the morning, and even if you shut it off after driving then restarting within acouple minutes. Any longer than a couple minutes you either have to try a couple of times or put the pedal down when starting. Any other ideas? I was kind of thinking that the fuel preasure regulator might need changed or even a new fuel filter. Please let me know.

Thanks!
Jeff

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. 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).

Failing CTS (Coolant Temperature Sensor). If the CTS fails, it will give out an incorrect reading to the computer. The computer controls how long to open and close the fuel injectors based on the information the CTS gives to the computer.

If you have not replaced your PCV valve, you may need to replace it. Normaly working PCV allows controlled air/oil vapor into the intake manifold. Failing PCV valve allows excess pressure and uncontrolled air/oil vapor into the intake manifold (stuck open PCV valve) or it prevents the air/oil vapor from coming through the PCV valve (stuck closed PCV valve) and ended up on the front valve cover where the breather hose is connected to the intake hose (very dirty throttle body, throttle plate, IAC).

Typical V engines have the PCV on one valve cover (usually rear) and hose then connected to the Intake Manifold. The other valve cover (usually front) is the breather hose and connected to the intake hose (it is suppose to just suck air in and then it exits to the other valve cover (rear) where the PCV is located. However, pressure within the engine forces the air/oil vapor out of the valve cover (front) and those air/oil vapor is now introduced into the intake system and causes dilute the air mixture for combustion and in the process gunk up the throttle body, throttle plate, IAC, etc.

[jlimrick]

Thanks! I'll give these ideas a try.

[jlimrick]

"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)."

Thanks for the help! It was the Fuel Pressure Regulator. I check it after the engine was running awhile and shut it off. Sure enough there was gas in the vacuum line. Thank you very much!!