1992 Accord 5 spd has 'classic' EGR symptoms. When warm, engine stutters slighty at low revs, smooths out by ~2.5K Car runs smoothly when cold. But... Just this evening I discovered that Car still stutters even when EGR valve vacuum line is disconected. The EGR system may not be to blame (??!) Observations: ------------- -General Check Engine light goes on after ~20 min of driving, sooner on a warm engine. Code '12' indicates EGR issues. No other codes. A few Weeks ago, I pulled two of the EGR port plugs (Cyl 1 and 3, neither transfer port) and found crusty but free flowing passages. Will pull the others this weekend, just to be sure. -EGR valve pulled, poked and prodded. (1 week ago) Valve smoothly opens under vacuum, (As I recall, it was fully open by about 7mmHG. Will test again to get more accurate numbers.) Diaphragm does not appear to leak. Diaphragm and valve plunger move smoothy. (There was a tiny bit of carbon build-up on the plunger that caused slight drag. Cleaning it hasn't changed anything that I can detect.) Valve seals reasonably well when closed - blowing on the output port, I couldn't detect appreciable flow at zero lift. The valve spring seems 'OK.' I didn't measure lifting force, but it seemed progressive and 'reasonable.' Measuring the valve's electrical resistance, there appear to be two complimentary outputs. As the valve is lifted, one resistance drops from ~5K ohms, and the other rises from ~1K to ~3K (the second numbers may not be terribly accurate - I observed that they changed and wasn't paying enough attention to the actual values.) - Vacuum meter tied into system, car driven. (Tonight) When monitoring the vacuum control line, the EGR solenoid output (Vacuum line 16 pressure) varies from 0 to a maximum of ~3mmHG. No more. Vacuum rises as engine revs build, then drops abruptly to (near) zero. When check engine light comes on, all solenoid activity ceases. As mentioned above, the car stutters (as before) even with the EGR valve actuation line disconnected/plugged. ~3 mmHg applied to egr valve stalls the car from idle. I haven't yet fiddled with the control solenoid or constant vaccum control valve. Any thoughts or advice? Thanks -Greg
the valve feeds a series of orifices in the manifold. where these connect to the main manifold pipes, these are relatively small diameter and tend to clog. can't remember the ages for transition, but older ones have the orifice drilling hole welded closed, later ones have them plugged with a blank that can be removed for cleaning. dealers carry resealing blanks. if you have the later ones, google this group for how to do it - there's a downloadable pdf out there somewhere. if they're welded, you can drill them out, but blanking then becomes an issue. if the manifolds are compatible, the ideal solution is get a later model year manifold with removable plugs from a junk yard.
