Hello all,
Please forgive me if I'm in the wrong area.
I have read through the countless threads on this topic and decided to tackle pinpointing the problem today. I am now more confused than ever after tackling the black box an am hoping someone can help fill in the blanks in my knowledge. After all, I'd love to be able to drive it around more than a couple minutes without the red "PGM-FI" light coming on.
My Car is a 1987 Honda Accord Hatchback LX-i Manual trans (Fuel Injected)
I'll start with things I know are good:
EGR Valve: Looks to be brand new, I removed it, no carbon at all, opens and closes with vacuum, no leaks. Looks like someone was here before.
EGR Solenoid: Clicks when you apply battery voltage, if there is no voltage the valve is open, meaning you can suck air through it. when I apply 12 volts to it I can no longer suck air through it so it seems to be operating
AIR Chamber??: It looks like cylinder with three nipples, two of them are close together. Top one goes to the EGR Solenoid, middle goes too the EGR valve bottom goes to the CVC Valve? its a UFO looking thing (Green and white saucer I think?) if you suck on the side that the EGR solenoid plugs in, it will send vacuum to the EGR valve, if you suck on the EGR valve side it will send vacuum to the EGR solenoid. If you suck on the bottom nipple, it goes nowhere... plugged or supposed to be that way? the flying saucer (what I think is the CVC) supplies vacuum with the engine running to the bottom nipple of the air chamber which leads me to believe that the CVC is working
Here is where I get confused.
After reading the forums, I've come to the conclusion that with the engine running, if I manually turn on the EGR solenoid while the engine is idling, it should kill the engine. It doesn't do that, engine still runs happily. So I checked for vacuum at the manifold (where the solenoid gets its vacuum from) and there is no vacuum there.. if I then suck on that hose I can kill the engine when its idling and the solenoid unplugged.
I guess it makes sense that there would be no manifold vacuum because if there was, with the solenoid being off=vacuum on=no vacuum (off appears to be default), it would be killing the engine at idle every time. So then the question becomes how is manifold vacuum controlled? There was no vacuum there at any RPM.
With this in mind I assume that would mean that the solenoid is being commanded on by the ECU at idle, the Black and yellow wire has 12 volts on it but the ECM doesn't appear to be grounding it at idle which would mean that its calling for vacuum to be sent to the EGR at idle. If I test for voltage using the ECM as ground it fluctuates between 2-9 volts. stays mostly at 2 volts. Is this a duty cycle thing with the ECU controlling the EGR valve at idle or is my ECM bad?
I'm hoping I'm making sense and that you guys can help me understand what's happening and how this system is supposed to work.
As fair as I can tell I have a bad intake, bad solenoid (appears to be operating backwards?) or bat PCM... or all of the above.
Ask any questions you have!
Thank you!
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