It has an auto trans, FWD, and had the CEL on for some time. The codes set were P2181, P0300, P0303, and P0304. I pulled the spark-plugs to inspect and check compression. The first thing I noticed is that the plugs are way down deep, and that "well" was very full of oil on #1, 3, 5, & 6. The firing-end of the plugs all looked good and clean, maybe even recently changed. Compression-testing was a real kick! All that oil around the plugs ran down into the cylinders, so compression on the oily ones was very high, >300 psi on the first... but it came down steadily as I kept cranking and testing as the excess oil blew out the open plug holes. One of them I checked repeatedly and it settled out at 190. The two non-oily ones (#2 & 4) were 185 and 190 on first pass, but then #4 steadily decreased with each try until it was down to 85. Later I put all the plugs back and ran the engine briefly, then checked #4 again (with all others in); it was back at 190. My conclusion was that compression is probably OK, at about 190 on all. I checked the plugs for firing while they were out and I was cranking for compression, all OK. By the way, these are "super-dooper" two-electrode plugs and they only fire on one electrode at a time; big surprise, huh! Although I would think oil is a pretty good insulator, cleaning it off the four seems to have cured the miss-fire problem. None of the P03xx codes have come back and the engine now runs smooth at all times. First question: how hard is it to change those valve covers, and how likely is it to be successful?. And just out of curiosity, how is miss-fire detected; by listening to the knock sensor?
Now on to the P2181 code, "engine cooling system performance"; that one keeps coming back. The only info I have right now is that "the cooling system has to be checked and topped-off routinely". I don't really know how often or how much is added, but get the impression it is checked frequently but little is added. It may be the frequent checking is in response to the P2181 and fear of over-heating the engine. The other tid-bit I have is that the car has been a money-pit and their regular mechanic is exasperated with it. My impression, after cleaning the plugs and driving it for a bit, is that there is nothing terribly wrong with it; I just need to get to the root of the P2181. The throttle response is a bit squirrley, but I think that is because it is an all-electric system. At this point I was stymied, as I don't have a scan tool and I couldn't even find the ECT sensor or thermostat to even consider checking; and batauto's server crashed. Next question, for Jim F: can you post some pictures of where stuff is located on that engine?
Good news is that this engine is mounted fore-and-aft, so everything is much easier to access that transverse V's I have seen. I have a block test kit and was going to check for combustion gas in the coolant, but my test fluid had turned to yellow over the years; I'll have to do that next session. At this point I am open to any hints or suggestions, but feel I have to get a real scan-tool to go much further. I'll post in "Auto Products" about that.
Now on to the P2181 code, "engine cooling system performance"; that one keeps coming back. The only info I have right now is that "the cooling system has to be checked and topped-off routinely". I don't really know how often or how much is added, but get the impression it is checked frequently but little is added. It may be the frequent checking is in response to the P2181 and fear of over-heating the engine. The other tid-bit I have is that the car has been a money-pit and their regular mechanic is exasperated with it. My impression, after cleaning the plugs and driving it for a bit, is that there is nothing terribly wrong with it; I just need to get to the root of the P2181. The throttle response is a bit squirrley, but I think that is because it is an all-electric system. At this point I was stymied, as I don't have a scan tool and I couldn't even find the ECT sensor or thermostat to even consider checking; and batauto's server crashed. Next question, for Jim F: can you post some pictures of where stuff is located on that engine?
Good news is that this engine is mounted fore-and-aft, so everything is much easier to access that transverse V's I have seen. I have a block test kit and was going to check for combustion gas in the coolant, but my test fluid had turned to yellow over the years; I'll have to do that next session. At this point I am open to any hints or suggestions, but feel I have to get a real scan-tool to go much further. I'll post in "Auto Products" about that.