I poked down the egr passageway that goes from the egr valve up to the upper intake manifold plenum - and was pulling out lots of gunk. So I bit the bullet and took the upper plenum apart.... no fun. The egr port was fully plugged with carbon where it enters the plenum. I cleaned it out and "pigged" the whole passageway with paper towel wadding, carb cleaner, and a stiff wire. The interior of the plenum was surprisingly dirty with carbon deposits as well - which I was not able to clean much - too many harnesses and hoses still limiting mobility of the cover...

Anyway, cleared the cel and took it for a test drive. so far so good. I'll have to see how this stands up over the coming days driving...

 

I know Honda has a bulletin in which the egr is removed. then the hole is drilled bigger. I dont know if it applies to the 4 cyl.

 

Not out of the woods yet. The car now exhibits a sever stall, sometimes while driving along at speed, where the engine cuts abruptly and severely. I'm noticing the tach needle dive to zero on these episodes, but the speedometer continues to read. Sometimes the episodes a very short - and it feels like a stutter. A couple times when idling at a light, the episode has completely stopped the engine.

This sounds like the ignition switch - and I think I did have it replaced under recall several years ago (I'll have to see if I can find the paperwork). However, I'm perplexed by the partial electrical loss - e.g. the speedometer continues to read. Might this be the ignition coil? Do failing coils exhibit this sort of intermittent failure?

No CEL at the moment, although it has been coming on intermittently. I'm suspecting that if this is an electrical problem that the loss of power is resetting the CEL...

 

Loss of tach signal and ignition suggests a coil or ignitor problem. There are diagnostics in the DIY section. For many Accords, a replacement distributor is not much more than ignitor or coil.

good luck

 

Did a pile more work:

- inspected the ignition switch for wear/pits - looks fine
- inspected the main relay for cracked solder joints - looks fine
- cleaned the battery posts
- replaced the ignition coil (original '98 Hitachi has some blue/metallic discoloration on the side where it engages the metal shim/bracket - possible arching or overheating I guess)
- replaced the distributor cap
- replaced the rotor
- replaced the plugs

Initial test drive seems good. To be seen how this stands up over the next few days. I plan on replacing the ignitor next if symptoms resume - painfully expensive part at $120. Unfortunately, I don't think the bench tests/diagnostics will work for me given my problem is intermittent. Troubleshooting procedures I read seem to assume I am starting from a point where the engine will not fire at all - which is not my case.

 

Will look forward to how you're doing, and what your "fix" was if you know for sure. I'm in the same boat, will post my own soon.

 

Well I'm still having chugging problems.... characteristics are a little different now - I'd characterize it more as a severe misfire/loss-of-ignition. I think this problem is electrical in nature.

I had it scanned and it's only showing the P0420 ("Catalyst System Efficiency Below Threshold") code now, which may be telling me that the cat really is not working, or the o2 sensor on the cat is dead. Neither would seem to be related to the misfire/loss-of-ignition problem though.

As I described previously, these misfire/stutter episodes are accompanied by the tach ticking to zero in a flash. I'm also hearing what I think is a relay click behind the dash when this happens - although it could be the tach needle whacking the zero stop. The other interesting characteristic is that when this happens, it clears the CEL! now what would cause that? It's like the ECM is getting spontaneously reset...

I've read that the tach ticking to zero is symptomatic of a bad ignitor - as the tach pick up is on the ignitor, right? Well I have not replaced the ignitor (yet) - it's a painfully expensive part (~$120). And I don't think a bad ignitor explains the CEL getting cleared. I'm wondering if the problem is more likely electrically "upstream" of the ignitor. Bad ECM? sporadic loss of power to the ECM? Caused by a loose connection? bad relay? broken/frayed cable?

Help and opinions much appreciated!

 

Can you get the car to stall out by shaking the key when the engine is running?

When you say the CEL is cleared, do you mean the CEL just turns off? Does it turn back on for the P0420? Or is the code gone?

 

PAhonda - I'll have to experiment with the ignition switch some more. I took it apart a couple weeks ago and the contacts looked good to me. Still lots of material there and no signs of pitting. I wouldn't think a bad ignition switch could clear CEL though. Sure, it can spontaneously kill the engine... but the CEL state (and stored code) would remain, right. I'd also pulled the main relay out and inspected it for cracked solder - nothing found. I'm starting to feel tempted to rig test lights to some circuits to confirm if power is indeed being lost during these episodes.

Regarding the CEL, the light just goes out when the misfire/loss-of-ignition occurs, and stay out. I don't have an obd2 scanner myself, so I can't check if its still holding a code despite the light being off.

 

The reason I asked is that when you turn off the car normally, does it take a while for the check engine light to turn back on after the initial bulb check?