EGR Control Solenoid only cuts on for 1 second

[zedjr10]

I got a 92 accord ex coupe. After replacing my control box i tested the vacuum from egr control solenoid while someone sat in car and revd engine to 3100 rpms. It cuts on for about a second of 7 to 8 in hg then cuts off. It did the same before i replaced the control box except the vacuum would only last for a split second. What would be telling the computer to cut the solenoid back off. I am assuming it has to be another sensor somewhere or maybe it is egr lift valve sensor cause diaphragm is cracked. I did probe voltage coming from lift sensor connector while key on and engine off and i get the required 1.2 volts. Or just maybe this is normal behavior while not driving(my service book aren't clear on this). Anyone ?

[edit]I forgot to say that when i get vacuum from egr control solenoid hose it is when it is rising to 3krpms and not when it sits at 3k rpms. It actuates it seems very shortly after i start revving up engine but before 3k rpms. I never see any vacuum at 3k rpms itself. My book sais something about the thermovalve b. I didn't know the thermovalve had anything to do with the egr or even what valve they are talking about. Do they mean FICV valve ECT sensor. [edit]

[zedjr10]

Problem solved. It was egr lift valve sensor. For anyone else who has same symptoms. If it is a super quick flash in vacuum less then half second it is probably a blocked passage. But for a 1 second jump and then nothing it is ur egr lift valve sensor. The ecu needs a signal above 1.2 volts to make adjsutments. If it doesn't detect a jump in volts it immediately cuts off egr solenoid. You can either take the top of the egr valve and unstick the plug(u might break casing though as the top wasn't intended to take off) or get another egr valve completely. Which is what i did. Got it from junkyard for 10 dollars. f22a6 engines have a different egr valve so be aware of that. They look the same but are different. Don't ask me the differences cause i don't know. Probably has to do with the size of chamber or flow. Anyways hope this helps someone else.