My 2000 Civic HX D16Y7 is now giving me a P1399 code as well as P0301, P0302, and P0300. It is stuttering mid range after it warms up and seems a little sluggish, though idling smoothly (a little low). It had been giving me a P1491 code back when it was running fine. I ended up replacing the EGR valve with a OEM EGR valve, and that got rid of the P1491 code. When I changed it out, first with an aftermarket EGR valve (Also labeled Siemens) I sprayed carb cleaner in the ports, but I couldn't get a wire to go anywhere in there. I have replaced the plugs, wires, cap and rotor and fuel filter to no effect. Also, I replaced the coil and adjusted the valves. The cylinder compression before the valve adjustment was 195, 190, 185 and 180. My vacuum gauge didn't tell me much, giving reasonable readings, but it isn't much of a gauge. There is no obvious vacuum leak. My timing light didn't show anything odd and the timing was in the right neigborhood on the pulley. It is frustrating that with all the sensors and the computer the car isn't really telling me what is wrong. Is it spark or fuel or are the ports for the EGR system plugged? If it's the ports, I'll need a model specific service bulletin because it looks like there is some stuff to take off for access. If it's fuel I guess I'll need to get a fuel pressure testing kit. I'm not sure I can really rule out spark. Could it be a sensor like O2 or temp or some other? Was the EGR code a coincidence or related? Some well reasoned advice would be appreciated.

 

The 00 HX has a D16Y5 engine not a D16Y7 engine.

Scrape and scrub clean the ports and passages of the EGR chamber:

 

Thanks RonJ. The diagram is helpful. Any chance of instructions. It's not right in front of me, but it seems like I might have to take out the injectors and maybe a few other things to get to the EGR chamber which I'm guessing is the key to cleaning out the ports. Is that the idea? Just gain access to the chamber and scrape and use carb cleaner or something? Oh, and take of the EGR valve which I have done five times now. Or do I need to take off more like the whole intake manifold? I take it from your advice you think that some blockage in there could be the source of my problems and not a coincidence?

 

I did like RonJ said and cleaned out the EGR Chamber. The stuttering went away and the CEL stayed off for 20 miles. It's got P1491 again which is insufficient EGR lift or something. At least the misfire codes haven't shown up (yet). It idles low enough to cause the a/c compressor to turn on/off/on/off rapidly but it has never stalled. Ideas?

 

Did you also clean the EGR valve? Also make sure all of the EGR system vacuum hoses are routed correctly.

 

Did you replace your spark plugs and wires? on the other code i agree with ron did you clean the egr valce and check the hoses?

 

I did clean the EGR valve, but I guess I could try one of the other two that are now in my collection. Also, I have replaced the wires, plugs, cap and rotor a few weeks ago when this began. There isn't a vacuum hose attached to the EGR valve and all the other hoses are where they have always been though it is kind of hard to follow them all where they go to be absolutely sure there is no leak. It seems like last time I was looking for leaks if I pulled one off it made the engine idle significantly faster.

 

For the HX with CVT, the EGR valve connects to an EGR control solenoid valve by a vacuum hose. The HX with a MT lacks the vacuum hose and EGR control solenoid valve. I assume that you have a MT. If so, you likely have an electrical problem in the EGR circuit or a bad EGR valve. The electrical tests are described on pages 11-261 to 11-264 of the 96-00 Civic manual that can be downloaded at either site 1 or site in my signature.

 

Thanks RonJ for the link to the electrical diagnosis sheets. It looks like it is the ECU. Can I just get another P2N and plug it in or is there more to it?

 

Also clean the passages in the manifold under the EGR valve. One of them goes all the way through the head to the exhaust manifold side. Might be best to remove the exhaust manifold and clean it from that end.

Try adjusting the idle screw in the top of the throttle body (NOT the throttle stop screw) to avoid low idle. This is assuming you've already cleaned the IACV and air passages for it.