rudypoochris Posted March 3, 2007 Share Posted March 3, 2007 So the Explorer passed smog. Everything seems fine, except for the 118/118 on the HC... Why are those so high? What usually causes high HC, lean, rich? Has EEC-IV learned that I like to floor it at that RPM sometimes and gives it extra gas there? Thanks! Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted March 3, 2007 Share Posted March 3, 2007 I'm pretty sure the high HC means running rich. I'd guess that your CAT may not be working as well as it could, as it should be able to burn off extra hydrocarbons that dont get burned in the combustion chamber. Mike Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted March 3, 2007 Author Share Posted March 3, 2007 I'm pretty sure the high HC means running rich. I'd guess that your CAT may not be working as well as it could, as it should be able to burn off extra hydrocarbons that dont get burned in the combustion chamber. Mike Thanks for the tip! 1300rpm is such a weird RPM to sample at though. Not sure Ford ever really instended the engine to be worrying about much more then staying away from detonation at 1300rpm. Quote Link to comment Share on other sites More sharing options...
GrommitZ Posted March 3, 2007 Share Posted March 3, 2007 My e36 failed 3 times before passing a couple of days ago. I failed on the same section 15mph HC's. I have the same limit of 118 and was failing above 140 the first 3 times. Along the way, I did a tune up, replaced the O2 sensor, checked for ecu code faults and tripple checked for vacuum leaks, the last being a good reason for high HC's. The last time I replaced the airflow meter, but I don't think it's the reason it passed. On the 3rd and last try, I was monitoring my O2 sensor voltage by splicing my multimeter into it. There are periods where the voltage was stuck around .8 volts when it should be switching between roughly .2 and .8 volts within a second. I first thought a vacuum leak cause my ecu to run in safe mode. It will do this because a vacuum leak can cause the engine to run lean and overheat the cat. To compensate the ecu will force the fuel injection to run rich, protecting a cat melt down. I did not observe a consistent pattern of when the car was running closed or open loop. I can't pinpoint what allowed me to pass, but on the last try, I drove the car longer, including a brief drive on the freeway in 3rd gear. I made sure the engine was never turned off once I was at the test only station. The smog operator was nice enough to run the car on the dynometer for 5 to 10 minutes to keep the engine and cat warm this time. I got hot enough that I could see what was probably oil burning off the head pipe and cat, coming out from under the car. My HC's dropped from 145 to 41 and my N0's dropped from about 300 to less than 10. I know people always say to really warm up your cat before the test, but I also think it's important to not turn off your car before the test. My car's O2 sensor would be switching fine one moment. Turning off the car and restarting would cause to go back to open loop briefly. I'm guessing that the real reason my car failed the previous times. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted March 4, 2007 Author Share Posted March 4, 2007 Interesting, thanks for the pointer. At least I do not need to worry until 2009 Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted May 8, 2008 Author Share Posted May 8, 2008 Just in case someone else with EEC-IV has a similar issue. I was just digging through old things and stumbled across this one. Well the reason why the HC's are high was because the engine coolant temperature sensor was reading way low. It only got worse after that smog check until the engine was stumbling and I found it out using my digital voltmeter. The sensor was reading 68 degrees of coolant temperature when the engine was at 185 degrees... that was when I yanked it. Problem solved. There are two replacement sensors you can get at Kragen, I believe both from Neihoff. One is a composite plastic of sorts, the other is metal (brass?). Don't buy the plastic one... we will see about this brass one in some time. If it fails, then I am going straight to OE. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted May 8, 2008 Share Posted May 8, 2008 man haha you guys are lucky. my Z isn't even close to passing emissions. Idle HC is 250 (limit 250) and Load HC is 1100 (limit is 250 again I think) CO% is fine though. I get to find out on friday whether or not I get to rebuild the engine and put new rings in. before the head rebuild to repair a warped head and compression leak through the number 3 exhaust valve, I was able to pass the load test at 120HC but idle would fail with 1100hc (because of the leaky valve) I'm really hoping I just see a charcoal looking spark plug, and not an ugly drippy plug. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted May 12, 2008 Share Posted May 12, 2008 the thermostats on explorers have a habit of opening soon or sticking open as the vehicle gets milage on it.if you dont use it in a very cold(snow) climate you wont notice this.this affects fuel milage.another thing to check is air charge temp sensor.getting the vehicle to run like the day it was new is the only way to try to get some fuel milage out of it.only use ford parts and motorcraft spark plugs.keep the tire pressures up-like 36 psi.when it goes to smog shop make sure its wasnt parked then driven directly onto the dyno. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted May 12, 2008 Author Share Posted May 12, 2008 the thermostats on explorers have a habit of opening soon or sticking open as the vehicle gets milage on it.if you dont use it in a very cold(snow) climate you wont notice this.this affects fuel milage.another thing to check is air charge temp sensor.getting the vehicle to run like the day it was new is the only way to try to get some fuel milage out of it.only use ford parts and motorcraft spark plugs.keep the tire pressures up-like 36 psi.when it goes to smog shop make sure its wasnt parked then driven directly onto the dyno. For a while my thermostat was stuck open, then I started getting into cars and repaired it. The car runs great. Only problem with the EFI really was a bad replacement ECT I installed. I get around 21 highway at 72mph so I am really not about to be complaining. Quote Link to comment Share on other sites More sharing options...
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