I failed inspecton yesterday.... My CO was too high...running too rich. There is also a bad miss that is worse at higher RPM's and my timming is off. I went throught the archived messages and talked to a few people. I pulled all my plugs the # 2or3 I can't remember was burnt (a sign of off timing, right?). Someone suggested that it's not likely a vacume leak because the miss would be worse at Idle....but maybe 2500rpms isn't enough to smooth it out. I replaced the plugs with new ones, cap and roter and leand the carb as much as I could. I also played with the timming after these other adjustments. It still misses. I have no pointer or timing light....Friday this guy I know is going to time it by the vacume somehow. I saw some potential bad news in archived messages suggesting that the miss could be caused by a bad cam lobe? I just don't know tell me what to do please. Checks I can run and such. One more thing, could the modual (sp?) that fires the duraspark be bad and cause this? It's the only old part on the car. Thanks Here are my test #'s for those who can make sense of them They are all too high. RPM 898 2559 HC PPM 852 and 2000 CO% 5.85 and 2.56 CO2% 6.7 and 7.2
Mile High emissions Yes you could have a bad cam lobe. You can also take out the air filter and see what happens. Might be a low flow air filter. Valve seals probably history allowing oil to be stucked past intake valve stems. Muffler might be old and plugged making the engine work harder and running rich. What do the plugs look like? Syn oil can also help out due to better oiling qualities.
well the motor only has 4000 miles on it so far after the overhaul....it only had 40k on it before that. The result is the same without the air cleaner. The plugs looked great except on the #2 or 3 plug the metal thing was a little burnt. I'm not burning any oil and I also passed the smoke part of the test. How can I tell if I have a bad lobe? It's hard to tell if the miss is only in one cylinder because it seems some what inconsistant. I should look to the carb some more but I want to know its not a bad lobe. The carb is new too but I changed the jets maybe I got something in it. I've noticed the miss but I can't remember if it started before or after I changed jets. or if it's been their since I put the motor in. It's hard to tell when I've never had it tuned right. I thought of another question too....I read that the oil presure is suposed to be in the range of 40-60 psi. When I'm at a stop light in gear with a warm motor it drops to around 20 psi is that always the case? I've driven a few fords and they all seem to do it.
JC the oil pressure action is ok. The quickest way to see if a cylinder is not up to par including the valves guides, springs is to invest in a vacuum gauge for some low amount of dollars, because I havenot had to by one for years. With the gauge hooked onto a source of full intake vacuum, a bad cylinder will show a sudden drop in the reading everytime that cylinder fires., and can be found most of the time by pulling the plug wires at the cap, one at a time and noting the drop in engine RPM and watching the gauge for the same drop in sync. The one that drops the least RPM and more on the gauge, is the bad one. A good vacuum reading on you engine should be 18 or higher if the cam is stock. A low steady reading can be a leak or ignition timing that is to retarded. Hope this will be of help as this is the way most of us would trouble shoot these conditions in the absence of expensive scope etc. Plug wires can contribute to this also as well as the cap and rotor.
I would start with the plug wires. I have seen several misses disappear after changing the wires. A thin spot in the insulation or a small break in the connector can cause a plug to not fire. Also you said that that you changed the jets in the carb. Make sure that there are no leaks in any of the gaskets after you put it back together. That can throw off the pressures in the carb and cause a rich condition. Did the car fail the Co at idle or at 2500RPM or both? I noticed that you are from Colorado as well. You might look into the Collector Series plates. You pay the registration 5years at a time and only have to have 1 E test when you first get them. You don't have to have another inspection as long as you own your car . The only catch is that your car has to be over 25years old. I think you have that covered. I did this for my 69.5. Takes a lot of stress off.
Your carb air/fuel mixture is probably too lean, I'd invest in a Hand Vacumn Pump you can get em at Autozone for about $20 they have many uses but one of em is testing engine vacumn I ran a test on my 71 today and discovered my mixtue was too lean as well (just recently installed a new PCV Valve). Also I have to concur on the spark plug wires new ones often do the trick. Mine used to miss really bad I fixed it by installed new Spark Plugs (Bosch Platinum - not Autolite) and new plug wires, miss dissapeared. 71 Grabber (Project Car) 85 Club Wagon 94 Taurus GL Sedan FFV
