I have a 93 F-150 with the 5.0l engine. My check engine light has been coming on with a code 33 generated. This is a failure of the EGR valve to close or function properly. To date I have replaced the valve and the solenoid that sits on top of the valve. I have also tried to clean the ports in the intake manifold. I am still getting a code 33 generated when I drive.

Any suggestions as to what to check next would be appreciated.

Santiago

 

This is the 97 to 03 forum but I will comment on your issue.
The code 33 is telling that the EGR 'movement' is not being detected by the sensor on it's top. That sensor is a vairable resistance not a solenoid.
Have you fully inspected the vacuum hose and source for cracks, splits, etc back to the EVR?
If the EGR gets no vacuum through the vac regulator, it will not operate and be detected by the sensor and causing the code 33.
If you find good vacuum from the intake manifold to the EVR solenoid and the hose is good to the EGR, look at the possibility of a broken wire on the sensor harness.
Good luck.

 

BG,

Thanks for the reply. I have not found any vacuum leaks but will inspect the hoses again. My air induction reactor pump is making noises and I wonder if this condition could affect the EGR operation.

Sorry for posting in the wrong forum.

santiago

 

To test some of the EGR action.do the following;
with the enguine at idle use a hand vac pump on the EGR and apply 10 or so inches of vacuum.
If the EGR is able to open with vac and hold the vacuum without leakdown and the idle gets very rough, the EGR is able to open, not stuck and no port is blocked.
The issue would then be either the vacuum supply or the wire harness.
Be sure the hoses to and from the EVR are on the correct ports as they must be correct being a 3 port device.
Good luck.