I have a vacuum gauge on the vacuum line to the egr so I know when it turns on and it never does? No CEL. Egr tested good. I got a new cvc and tested good. I tested the egr solenoid and checks good. I swapped ecu no help. I ohm the orange/blue strip wire from egr solenoid to ecu and was good. My question is what sensor or sensors does ecu need to engage the egr solenoid? Maybe I have a bad sensor to the ecu so egr solenoid can't engage? Any thoughts???

 

There is suppose to be a separate control solenoid, You might want to check it out.

 

Yes the egr solenoid. I followed the manual and it tested good. I even ohmed the org/blue wire to ecu.

Does anyone know what sensors the ecu requires before it will allow egr to engage?

 

There are no sensors that tell egr solenoid to open the egr. Best thing you can do is apply power, or ground to the solenoid. Make sure you unplug it from the original harness though. I don't want you frying the ecu.

 

I am referring to sensors telling the ecu to turn on the egr solenoid? The egr doesn't open when ever it wants to. Doesn't the ecu take inputs from say the map sensor for vacuum load and tps for throttle position and thus only telling egr to open when cruising right? The egr is not open at idle or full throttle correct? SO what all sensors does the ecu require before grounding the egr solenoid to turn on thus allowing vacuum to open the egr?

Also in my previous post I had mentioned checking the egr solenoid as per the manual and it checked fine. So did the egr valve and the cvc.

 

Honda doesn't use EGR like other manufacturers do. It's rarely open. Try cruising around above 3000 RPM (something you never do in a VX). See if that gets it to open.

It wont improve fuel economy if that's what you're looking for. People who measure fuel economy in real time have found that forcing the EGR open hurts MPG.

My VX is over 300k, I haven't gotten around to cleaning up the EGR and intake manifold yet and I'm sure it's never been done. Still no CEL for it. Consistent 45mpg around town without even trying, 49 when I'm driving conscientiously (and that was before I noticed my TPS was damaged and out of adjustment).

 

I have tried 3k, 4k and 5k? It never opens?

Well I had a bad stumble only when cruising and found my cvc bad. Ever since I replaced it my mpg's dropped to 42ish and I drive 90% highway and was getting 55 mpg! And with 293k on it she still has great compression!

So I'm pretty sure like every car out there the egr only opens when cruising based on sensors telling ecu when its time to open. What sensors? Anyone???

 

The ecu tells the egr when to open, it does its own calcuations and tells the egr solenoid when to allow vacuum. Did you put the the vac gauge between the solenoid and the egr?

 

Yes, I have the vacuum gauge between the solenoid and the egr. It never moves. I have the 12v on the fuse side of egr solenoid. I ohmed the other side to ecu and checks good so according to manual it says swap ecu. I did that and no change. So I was hoping it might be a sensor feeding the ecu like maybe map or tps or what else I don't know that ecu needs to tell egr solenoid to turn on? Thus far I have no cel, new cvc, checked egr, checked egr solenoid and tried another, swapped ecu? So I'm guessing it would be an input sensor that ecu isn't getting?

 

you provide voltage to the solenoid amd nothing happens than its your solenoid

 

yes it does. it works fine. im starting to think no one reads my post??? the manual says if u put voltage on it and it works then ohm the org/blue stripe wire to ecu and if thats good then replace ecu. i have done it all and it all works? i know one know what inputs the ecu needs to turn it on?

 

Than whats the ecu you're using?

 

stock p07-a00 and swapped with another stock ecu

she is all stock no mods

 

So if you swapped ecu's and you still not getting any readings from your vac gauge then its best to say that you have to meet certain driving conditions in order to have the egr activate. For instance you can warm up your car and apply power to the egr and it should start to sound like its ready to die, or so I was told. Also the egr does not take 12v, I think the ecu sends out a 5v to the control solenoid.

 

yep! i know. when i try something i drive it to work 30mi one way of 90% highway driving. the solenoid must not be getting something to turn on?

yes it does. one side is 12v from acg(s) 15a fuse and other side gets grounded from ecu. pg 11-134 of service manual. i followed the t-shooting from the manual.

 

The egr valve only engages at idle to reduce emissions. The car runs lean at idle and to reduce the hydrocarbon emissions honda had to use an egr valve on its lean burn engines.

Your egr should only operate when the vehicle is cold to help get the car to normal operating temperature.

The egr does not engage during any other cycle for any other purpose

 

hum? i dont think so? egr only engages while cruising at a steady speed and when fully warmed up.

http://www.agcoauto.com/content/news/p2_articleid/207

 

From the link above I found this -

"Electrically operated EGR valves are also common. These may have up to three valves in one unit. The engine computer can open and close any or all the valves in response to input from sensors. For instance the electronic temperature control or ETC sensor informs the computer when the engine is cold. Knock sensor(s) signal valve clatter or detonation. A sensor built into the unit informs the computer of the position of each valve."

This is what I am looking for? Anyone know what inputs the ecu needs to engage the egr solenoid?

 

The eletrical ones are the newer models. you're using the old style egr, which is a vacuum top. The newer ones don't have a separate egr controller and does not need a vacuum hose. They are also 5 wire egr. Your's, and mine, are 3 wire egr w/ an egr solenoid.

 

There are 2 different kinds of egr valves as mentioned.

The egr has nothing to do with lean burn and if you have no check engine light the valve is operating normally.

 

If you're trying to figure out lean burn than you ned a wide band a/f ratio gauge. YOu hit that 20:1 thats how you know. You can use the vacuum gauge to help you with your throttle usage.

 

How are you testing it with a vacuum gauge? Do you have this gauge run to the inside of the car and are monitoring it?

EGR only opens during deceleration, usually from above 55mph. I've data logged Hondas and very rarely see the EGR opening. The only Hondas I ever see where the EGR will open is on the V6 and it only happens for about 1-2 seconds while decelerating from 55+ mph to 35mpg with no brakes applied.

 

yes.

ok, thks. I have never seen it open ever at any speed. With the vx being the renown mpg car that it is I would assume it opens much more than other cars especially since it has the cvc for that reason. idk though? Was hoping someone here had vx knowledge.

 

The thing is...............what are you trying to gauge by checking the egr to see if its opening?

 

The various sensors the ecu needs the turn the egr solenoid on? From the 92-95 service manual page 11-134 is the drawing I am referring to. It is egr t-shooting section and does not identify the various sensors. If one of the sensors are bad then the egr system won't work.