Can anybody offer me any advice on where to go from here. I have a 2000 Honda Accord 4cly auto with 260,000km. I bought it at about 150,000. It has run great but recently has been not quite right.

The fuel pump failed about 3 months ago. It stopped turning and could be started with a gentle tap on the housing on the top of the tank. I changed the pump to an AC Delco which I installed myself. That issue appeared to be resolved but it did turn on the check engine light twice after I changed the pump. I did not bother to read the code as I assumed the engine was just re-learning the new pump.

Recently the fuel economy has gone down (but it is summer and the AC is on full time). The car seems to miss at low rpm with the AC on. Not really bad but enough to notice. Now the check engine light is on steady and the codes stored are P1399 generic P0172 Generic system too rich and P0304 Cylinder 4 misfire. I recall changing the cap and rotor as well as a set of plugs but I really cant recall how long ago it was. I changed the air filter a few days ago and that did not help at all. I also pulled the plug nearest the driver side and it still looked like new.

Should I do the cap rotor, and plugs again? Or am I dealing with a bigger problem?

Thank you in advance for your help!

 

The problem and codes may be caused by clogged EGR ports and/or the EGR valve stuck open.

 

Thanks for your advice does it make any difference that this car is not subjected to short trips. This car is a daily commuter and pulls a one hour drive over a steep four lane mountain pass at 110 - 120 kph. It has done about 100,000 km under these conditions.

I do recall that the last Honda accord that I bought (a 1994 with 160,000 km) was a grocery getter and had done a lot of short trips. When I started commuting over the pass it started throwing codes but quickly cleared itself out and started running good. I sold it with about 340,000 kilometers and never had any EGR issues except a few codes when it was new to me.

I think I will pull all of the plugs, wires and the cap and rotor before I dig into the EGR ports on the manifold. From what I read on the forum the EGR usually throws a specific code to the EGR. If I have to do the EGR I certainly can I just don't need the job right now.

Thanks again. I'll post back the results later.

 

I put in a new set of NGK spark plugs tonight. No change. The old ones did look worn but all four are a nice healthy tan colour. Resistance on all four plug wire ranged 11,000 - 16,000 ohms. Spec says reistance must be less that 25,000 ohms. Also ran in dark garage no arcing. Wiggled connectors no change detected. I have a set of NGK wires but chose not to change them. Checked cap and rotor and they both look fine. Coil electrode looks good too.

The car misses badly when cold and throws 1399 instantly and after driving around a bit is also threw 0304 misfire cyl 4. I am going outside to test EGR per my Haynes Manual.

Do you still think it's EGR??

Thanks

 

Okay. tested the EGR as per the Haynes manual. Continuity between terminal 1 and 2 and terminals 1 and 3. Check. Warm car up then apply ground to terminal 6 and positive to terminal 5 vehicle should stumble run rough or stall. Check. Car stalled. I pulled the EGR and cleaned it. A bit of black soot but not bad. Apply voltage valve opens remove voltage valve closes. Ports on manifold fairly clean with a small amount of greyish soot. Put compressed air through to manifold. I think it is coming out behind the throttle body throttle plate but it is hard to tell. Put a flexible wire through manifold egr port into manifold. By the length of wire I was able to jam in I think it is clear into the plenum. I felt inside throttle body EEEWWW black oily goo. Yuck! Re-assemble egr and fire it back up. I sprayed choke and carb cleaner into throttle plate and opened throttle plate manually.

Test drive. Miss from 1000 to three thousand RPM. and the unidentified code 1399 again.

Should I take the plenum apart and clean it. I don't have a gasket for it so I think I should wait till I get one.

Advice??

 

update. changed cap and rotor as well as plug wires. No Change. Pulled wires on running engine. Cyl 4 seem to not change much plugged in or not. 1-3 causes an immediate stumble. Compression solid 170 on 1,2,3 and 185 on cyl 4.
Pulled injectors to clean them they look ok.

Could really use some advice here.

 

ok Pulled the top of the plenum no blockage on egr port. Bit of dry soot. That's all. Injectors a little out of spec as 12.8 -13.9 ohms Spec says approximately 13.9 - 19 ohms. I can hear them clicking with my stethoscope. don't look too dirty?

Could really use a little help here.

 

Have any pic's of the plenum?

Also so we are clear, the cyl are numbered 1 thru 4 with #1 being the "belt" end of the engine and #4 being the "trans" end of the engine.

Can you swap the injectors between #4 and #3 and retest.....you pulled #4 wire and no change in the engine, yet the other cyl's did.

 

Sorry no pictures of the Plenum. I already cleaned and re-assembled it. It had a black oily tar like substance coating the entire inside. but the egr passage only contained light soot. I suspect I can thank the long trips at high speed and load for burning out the egr area and keeping it clean. I used a thin coat of Aviation high Tack gasket on both sides of the steel plenum gasket. I hope that was a good decision. I can't see why not.

Unfortunately I cannot identify which injector is # 4 anymore. I had a momentary lapse and soaked all four injectors in a jar of injector cleaner. I forgot to label it. DUH!!! The o ring on the tips are all brittle. I could not get an o ring kit in my small town so I have a set of nitrile o rings that I am planning to use on re-assembly. I am cautiously optimistic that a bad injector is my cause. Yes # 4 was not pulling it's weight and #4 injector was also not as crisp when listening on my stethoscope. I hope that cleaning the injectors will at least temporarily solve it and I'll know if it pops back up again it needs injectors.

I will re install them today and flash it up. I will report back the results. As for cyl id yes. I am calling #1 at drive belts and #4 at transmission side.

By the way does anyone think valve clearance could be my issue? My old accord never moved the entire time I owned it and I have not checked this one ever. There is a bill for it from the Honda dealer in the glove box but that was a lot of miles ago.

Thanks

 

PROBLEM SOLVED!

So I put it back together and fired it up. It threw P0505 three times and hunted from 1000 - 2200 rpm. I checked everything like vacuum hoses and wiring harnesses including the throttle cables. No issues were found so I went for a short drive. Maybe the computer just had to learn how to run the clean injectors?????

After I cleared the codes and went for a short drive it settled down and ran great. I just got back from a decent test drive and it is fixed. The car pulls hard, idles smooth, and is not throwing any codes!

I am now sure that a dirty or clogged injector was the issue. I did a final cleaning on the injectors before re assembly today and noted that one of them was sticky. I used a punch to manually push up on the valve and after a few cycles it was as smooth as the others.

If I get a P1399 again I will invest in a set of injectors.

I am still contemplating checking the valve clearances. I am a big believer in preventative maintenance but in my previous experience they never moved anyway.

Should I check the valve clearance or save my time??

Thanks