i just purchased a 1992 chevy van at a auction it has a5.7 v8 and it failed the emissions e check in my state of ohio.on the nox gas it was 20.697and the limit is 12.69.i have checked out the egr valve and this is what i have found the vacuum is good, the egr control solenoid works when i put a ground wire spliced in to the wires for the solenoid there is 12 volt power on one side.also when i ground out the other wire the egr opens completely and stays open til i remove the ground.and when i press up on the egr valve i have heard the motor will drop and almost die but when i press on my egr it has no effect on the engine at all.after it warms up a little the egr valve will move just a little with the gas pressed,so i unhooked the vacuum off the egr valve i put my finger on the end and gave the motor some gas and only got vacuum for a couple of seconds and then nothing.but when i hook another strait ground to egr solenoid the egr opens all the way.i have heard the egr passages sometimes clog up so i removed egr valve and it was not carboned up to bad no chunks or any thing and i looked in the egr valve holes and cant see any build up of blockage.also while i had the egr off i started the engine and exuast came out of the egr holes is this blocked.is there something im missing.help????

 

also there are no codes stored and no codes thrown on the van

 

This breaks a fundamental rule on the board that all topics must be 3rd gen, but I'll allow the discussion only since it also applies to SBC's in 3rd gens.

If while the engine is idling you open up the EGR valve and it doesn't make any difference in how the engine runs, you have blocked passages somewhere. The valve is pretty easy to check, but the intake passages can be plugged in places not visible just by removing the valve.

The fact that it ran with the EGR valve removed, and exhaust came out of the intake boss, is pretty good evidence that the intake vacuum passages are blocked. Remove the intake and replace it, or have the one on it now tanked by an engine machine shop. If the intake is aluminum, it should be "washed", not tanked in a caustic cleaning solution. You could try to clean out the passages manually, but the shop can get everything out/off of it.

 

if there is a blockage in my intake would that cause the egr valve to not work properly.it seems to try to open but like it loses the ground or something.one wire on the control solenoid is 12 volt is the other wire the ground? or is it a hot wire too lower voltage?when i hook a wire into the one i think is a ground it opens the egr valve.whats wrong.am i doing something i shouldnt?

 

Certainly not the way I would do it. I'd disconnect the solenoid connector, apply a 12v jumper to one terminal and ground to the other, and with vacuum applied (engine running or external vacuum source), see if the EGR valve opens.

 

when the key is turned on, the solenoid has power on one side and i do jump a ground to the other wire, and it does open wide does this mean my ground is bad thats going to egr solenoid.i have also tryed to cross the wires too and the valve did not move.it only opens when i add a ground to the wires for the egr solenoid.does the computer control the ground for the egr solenoid? if one side is hot and i have power checked with a troubleshooting lite and when i tryed to do the opposite and check the groung the lite did not come on like the ground is bad?

 

When the ECM wants the EGR valve to open, it provides a ground to complete the circuit.

Perhaps I didn't read your account carefully enough, so jumping the ground wire to ground would open the solenoid and therefore the valve (if vacuum is present).

I'd still bet you've got plugged intake passages. Very common.

 

have you ever heard of someone that has unblocked intake passages with the intake on the engine.im looking for some suggestions on how to get through a blockage i have tryed a clothes hanger and have no idea which way to poke i have tryed but feels like im getting nowhere.got any hints for me.thanks for all your help.ken

 

Only if the blockage was in the exhaust portion, and close to the EGR valve.

Best way is to get it off and clean it out properly. Or, "upgrade" the intake while you're at it.

 

ive taken my intake off and i am going to have it put in a hot tank to clean it,there are some plugs in the top and bottom of the intake ,DO THOSE PLUGS HAVE TO BE REMOVED TO HAVE THE INTAKE HOT TANKED?