Car: 2000 Accord lx 2.3l vtec f23a1 manual trans
Problrm: rough idle, misfire cyl 2, 4, and random

Ive had a couple EGR related codes, 1st was regarding insufficient flow so I cleaned the channels and valve. That took care of the code but then the code egr lift insufficient showed up (P1491). Currently troubleshooting this code.

I did the following test- started the car and applied voltage to the egr valve, the idle did not cough or stumble or stall as it should have. I know the egr valve opens with voltage, and I could hear that it was opening during this test. I then took the valve off, plugged the manifold side egr channel with a shop rag and started the car again. No exhaust came from the egr exhaust side channel. The channel is as clear of carbon as I can get it. I shut the car off and poured a little sea foam in the channel to see if it would drain, it didn't.

My question is this- if I remove the egr valve, plug the manifold side egr channel and start the car, should there be free flowing exhaust coming from the egr exhaust channel? If so, and the channel is clear, how would I get further in to unblock whatever is blocked? I don't have any idea what's beyond the exhaust channel and can't seem to find any clear diagram that shows this, or how to get to it. Any help or advice would be great.

 

Did you clean the channel on the intake side or the exhaust side? The intake side should have vacuum when the engine is running. The exhaust side should have exhaust gas coming out when the engine is running and EGR is removed.

The exhaust gas should be present at all times, because the exhaust gas must come from the exhaust manifold. You'll have to look at the exhaust manifold and follow the port from the EGR valve through the exhaust manifold. Hopefully the casting on the outside of the exhaust manifold will be obvious on how the exhaust gas gets to the EGR valve.

 

Thank you! Ive been everywhere posting waiting for this answer. I assumed that was the case, but didn't know for sure.

I did clean the manifold side channel and the intake plenum, that channel has a very strong vacuum at idle.

The exhaust channel disappears into the head by where the egr valve sits and from there I have no idea where it goes, I haven't been able to locate it on the exhaust manifold, I've been assuming it's all internal, but surely Honda's engineers would have given thought to access... right?

 

I managed to clear the deep exhaust channel blockage with throttle body / air intake cleaner, stuffing the end of a tight fitting rubber fuel line into the channel and forcing air (and the cleaner) through the blockage. It could be clearer, it's still not flowing as easily as it should be but I ran out of time. I'll maybe give it another go and see if I can clear it all the way when I have time to work on it again.

My idle is still rough and misfiring, according to my 02 sensor and stft it's running lean at idle and rich at 3k rpms, so I read that these results indicate a vacuum leak. I'll do some testing and see if I can find it. If so, hopefully fixing that will fix my terrible idle once and for all.