I pulled my codes and am getting a code 33 while the engine is running test and as a continuos code. The egr valve will bleed off a
little bit when I check it with a vacuum pump. I hooked up the vacuum pump to the vacuum line to the egr valve and when I accelerate the engine it shows very little vacuum. Could the problem be the evr valve? Will it change the power or performance of the engine if I keep driving the truck the way it is.

 

My sources say that a code 33 is that the EGR did not open or opened itermittently. This won't harm the truck but will give poorer performance and the ever annoying warning light. I had a similar problem that turned out to be the EVR solinoid that controlls the EGR valve. It is up near the ignition coil, just follow the green hose from the EGR to it. It is electrical, computor controlled, telling the EGR when to open' Mine was open all the time. I took it apart, Carefully!, and found that under the bottom cap there is a small spring and a small rubber coated metal disk that is the control valve. There was a small piece of grit stuck to the valve there by letting the vacuum to the Egr to be constant. This may be your problem . Another problem that Fords have it the vacuum canister(juice can) on the passenger side wheel arch rusts out and leaks. I just mickey moused the plumbing to got engine vacuum at idle and then tested my can for leaks and the Egr for operation.( I have since bought a vacuum pump for this purpose as well as brake bleeding, very worth while) If you apply vacuum to the Egr at idle the engine will run rough and then most likely stall. If it doesn't the EGR may be blocked with carbon or the diaphragm my be hooped. EGR gasses only enter the engine at a cruise speed. I blocked my EGR with a plate discribed in other EGR related problems listed in these forums and get no warning light now although the system still thinks that the valve is doing it's thing! I suggest you cruise throug other threads on the EGR subject to find suggestions on this topic. This forum is a god send to us Ford owners who would rather fix it themselves than pay a shop to do it.

 

I checked the EVR valve and it doesn't hold any vacuum at all. I used the procedure in the Haynes manual. I guess I'll replace this first. When the egr valve is not working properly what will the computer do to compensate for this???????????? Will it make the truck run leaner or richer or change the timing???????

 

I've had the same problem with a 90 bronco.Code 33.I too checked the evr(solenoid by the coil)per the haynes manual and it would'nt hold vacuum.Replaced the solenoid and the new one does the same thing,won't hold vacuum.Did I get a bad solenoid?Of course ford dealer won't take back an electrical part.The manual says that the pcm applies ground to the circuit and the evr opens to put vacuum on the egr and open it.Mine will do that.But,it says that when the solenoid closes it vents vacuum to close the egr.Now the manual says to test it with the plug disconnected(no power) and it should hold vacuum.But if it vents vacuum when it's closed,how can it hold vacuum?I realize that if it vents all the time you would have a vacuum leak.I'd be interested to see what happens when you replace yours.I also tested my neighbors truck and his solenoid would not hold vacuum when closed either.Call me confused.I guess worst case right now my egr is not opening,same as having it blocked off.It's not pinging,other than that I don't now what problems it could cause.

Billy