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.

 

If the valve is opening and the idle does not change you are not getting EGR.

 

Correct, due to no exhaust coming from the exhaust channel. The channel has been cleaned out as far as I can get with a fairly long bore brush. So whatever blockage remains is in there deep, looking for advice on getting in there, I have no idea what it looks like or how to clean it beyond the channel.


Edit: this is assuming there should be exhaust gases flowing freely from the exhaust channel at idle and according to the test explained above.

 

You need to clear after the valve as well. Have you looked at that?
FWIW I do not believe the EGR is responsible for you stated problem.
Have you checked any of the basics like fuel pressure?
EGR will cause your problem if the system is clean and you are getting EGR at idle due to a open valve. This is not a problem when you don't have EGR flow.

 

I understand... the way I decided to troubleshoot this is to take care of the trouble codes first, the egr is coming back as the primary "red led" issue. After that at least I'll know if it is or isnt the problem. At the same time I've got new o2 sensors coming and a new map sensor so I'm actually hitting it from a few different angles. (Also a new egr valve).
So far I've been looking at air and ignition, haven't made it to fuel yet. There was just so much carbon in my intake I figured that's where to look, along with the trouble code it just seemed to make sense.

When you say I should clean after the valve, if you mean the manifold channel and intake plenum, I've cleaned those thoroughly.

 

I don't think you understand. If the passages are plugged you get no EGR. The idle problem to be caused by the EGR would be because the passages are open and it's getting EGR when it shouldn't. That EGR is not causing your problem unless the passages are open and the EGR valve is open at idle.
Do this. Take the valve off and block the passage. Does it still idle bad? If not, your valve needs to be replaced.

 

I do understand everything you're saying, what I'm saying is I was addressing the EGR codes before anything else to get rid of those trouble codes. I know at idle the EGR isn't supposed to be open and would only be causing the idle trouble if it had a vacuum leak in the valve or from the gasket, or if it was stuck open. These things aren't lost on me. At any rate, I managed to remove the deep exhaust blockage (mostly) and replaced the valve, the P1491 error is now resolved and I'm moving on to the next step.

According to the obd2 results, and from what I've read, I have a vacuum leak somewhere that's only bad enough to affect the idle, not enough to affect the engine at higher rpms, so I'll try the starter fluid test, and if that shows nothing, a smoke test. Idk why it couldn't just be the map sensor, I would have been done a long time ago.