minilogoguy18

You can block the valve, just don't raise the RPM above 3000, the valve does not operate at low RPM, it's basic misfire troubleshooting. How will you know the valve is hanging open at idle if all you did was unplug it? Carbon build up a seat wear will cause a EGR leak making the mixture become rich by introducing an inert gas at a time when the PCM isn't programmed to counter it by reducing injector duration. That method of unplugging the EGR wont test anything but the detection circuit in the PCM and MIL bulb on the dash lol.

Shorting the SCS just removes 2 trip monitoring and sets it to single trip. All PGMFI DTC's require 2 consecutive failures to set a permanent DTC otherwise it's just stored as temporary which the PCM can erase on it's own if another few drive cycles pass without a problem found. The only DTC that can trigger a permanent DTC on 1 drive cycle is a misfire that the PCM considers to be catalyst damaging since the PCM gives no ***** about the engines performance, only the safety and performance of the catalyst.

A P0420 isn't hard to trigger since catalyst performance is the main goal of the PCM, it's difficult to test without the right diagnostic equipment. Comparing output voltages between the main and secondary sensors to judge catalyst performance with a multimeter wont be easy. I'd say if you haven't gotten a P0420 DTC yet then the catalyst is OK.

backinblue92

iTrader: (1)

Ok wow alright while I understood what u wanted me to do to troubleshoot this, thank you so much for going into more detail there. I fully understand exactly what it is I'm trying to do here with the egr now, and what it means.

Yeah I was gonna say, unplugging the egr would tell me it's unplugged but wouldn't close a valve that refuses to close due to wear or carbon buildup.

Bad news is I tried after work tonight to simply remove the egr and the nuts stripped. Both of em, like they were made of putty. Not sure what happened because it was torqued to literally 25ft-lb 2 weeks ago. So I have tomorrow off. I'm gonna go to the shop and pay them to borrow their obd2 scan tool if they don't just let me borrow it in the parking lot. And I know exactly what to look for here now. I'd imagine if the egr valve is hanging open at low rpm, it is doing it all the time, so triggering a single cycle dtc would tell me for sure. It would be deleted in time, sure, but I'd be seeing it in real time.

Also, my catalyst is brand spanking new. Magnaflow CA legal cat. The first thing I did after the first fail was change the o2 and have a new cat put in. Exhaust tone changed, and I'd imagine no catalyst is as good as oem, but anything CA legal should do the job well enough that I shouldn't still be looking at the cat. Besides, being obd2, I'd throw some kind of dtc or even a cel if my cat wasn't functioning properly. I'm starting to believe my old cat wasn't even bad, but I was gross polluter on HC (220), CO (.7%), NOX (2100ppm) at 15mph after the first test (and passing at 25) then by the second test, after the new cat and o2, I was only missing on HCs at 15mph. 3rd test was with iso heet, brought everything down further but not good enough. 4th test was a pretest with denatured alky and a massive fail at 15, yet another passing at 25.

So the cat is doing all it can, but basically those horrible gross polluter numbers at 15 are still happening and I needed to source the issue. My money has been on a major failure that is affecting air/fuel mix at low speed/rpm.

If it also means anything, my 15mph test is run at 1750rpm under load (when presumably under load the egr should be not open). The 25mph test at 2000rpm, no load cruising. It tells me given the mass variation despite only a 300 rpm difference, that it's load vs no load. Something, when under load, is causing a super rich mix. Egr is the only thing that makes sense.

Thank you very much for your time in explaining not just what you think, but the why and how. I don't expect to be spoon fed without getting my hands dirty too hope to report back tomorrow literally happy to have to replace a $150 part. If it means the end of this 1.5 month saga. Lol

backinblue92

iTrader: (1)

Also, forgot to ask, do I need to reset my ecu before I jump the SCS for a new drive cycle? Or would I rather keep my stored cycles and jump it in the hope that if it doesn't detect a dtc it is already stored in short term memory?

backinblue92

iTrader: (1)

And here are the corresponding charts for the values:
















Used a friends obd2 scanner. This was all at idle. I know I've already gone over those numbers but thought I'd post pics anyways.

There were no temp dtc or permanent dtc, even when the SCS was jumped. So all systems are still normal.

I had to hack off the egr bolt nuts which damaged the studs too since they were not coming off now and got stripped. So for the moment, until the new studs and nuts arrive from Honda and I have more time, I'm at a standstill. I'll be able to get her on a dyno for a pretest with the egr blocked off for the 15mph test when I can.

Although this presents a question: if the egr valve isn't fully closing when not in use, aka when idling like I was when I did this today, wouldn't that be present in my fuel trim? Or shown up in some way?

Edit: so I'm hearing from a friend my MAP value is really low and it should he more like 14 inches of mercury, not 7.7. So there's high manifold pressure due to low vacuum? And either my map sensor is fucked or I've got a manifold problem.

backinblue92

iTrader: (1)

Ok so what I have ascertained from my research is that I have one of two issues going on. The manifold pressure is either low, indicating a vacuum leak, or the map sensor is bad.

While I did test the voltage of the map sensor, I did not test it with a vacuum guage. As it stands now, the map is reading 7.7inHG at idle when it should be well above that. So it could be sending the wrong values to the PCM this whole time. I'll be picking up a new map sensor tomorrow and testing it at idle with my buddies obd scanner thurs to see if that value changes.

If it does not, that means I have a intake manifold leak. Which could end up being the egr valve not fully closing, but it'd have to think that would at least create a dtc if not cel.

I double and triple checked every vacuum line against the honda diagrams, all is in order. I'll have more info thursday, but I feel I've finally narrowed it down to a specific couple ideas.

Anybody have any input or common sources of IM vac leaks that I may not be thinking of? I also identified what could be a symptom of the map sensor or overall low manifold pressure- when slowing to a stop, when I push in the clutch the rpms will drop to 300 for a second as I stop before settling back at 750. And now that it's been brought to my attention, there is a slight initial lag under acceleration.

backinblue92

iTrader: (1)

Well the intake manifold vacuum turned out to be fine, in terms of the numbers. Problem is, it bounces between 21"-22" so fast that u can't barely even see the needle. So it's still misfiring. With no DTCs.

So I'm going after the egr like was suggested before I got distracted with thinking it was the MAP because of the low vacuum the scanner read. Apparently, the scanner doesn't account for atmospheric pressure. So when it read 7.7", I needed to add 14.7". Lol that sucked. And wasted my time.

So one last resort. I see nobody has any ideas anymore but I'll keep updating til it's fixed.

holmesnmanny

When you cleaned your egr ports, did you clean the tiny port holes that lead down into the runners or did you just clean just below the egr plugs ?

ludea17

TimiK

ludea17

ludea17

My catilytic converter was gutted.... That was my problem.

snobordboy

That will do it, our emissions test here are rather strict.
My Lude has been sitting in the shop for a couple of years now basically, so I will need to have a new custom pipe made to adapt my new header to the stock cat if I ever want to register it in Colorado again.