i just aquired an '89 jeep cherokee and i need to get it to pass smog, i know the smog guy and he said that he didnt think it would pass when it was on the machine, said that just a set of plugs might do the trick

now i wasnt actually there when it was on the machine nor have i heard it run in person as of yet but it does run and drive, just runs a bit rough i guess, so i was going to put in a set of plugs and give it the seafoam treatment and cross my fingers

any ideas to further the chance of it passing?

its got the 4.0L with 208k and some change on it

 

Full tune up.. cap/rotor, plugs, plug wires, etc. Oil change, try running some seafoam in the cranckcase and thru the intake before your oil change. (NAPA has a sale on ALL OF THIS STUFF THIS MONTH). Make sure it has good fuel in it as well.

 

the oil was pretty clean when i checked it, might have bad fuel in it, i dont know how old it is

im going to check on prices tonight and go from there, thanks

 

what would the best brand of plugs be to put in?

i run champions in my truck, what do jeeps like the best?

 

If you are going to Seafoam I would do it before the tune-up, as some people say it can foul plugs if you do the Seafoam in the fuel tank as well. Do a search and you will get good descriptions of the cleaning process.

Everyone here seems to like straight-up Champion Copper Plugs, $1.89 per. I got some Champion Platinums ($2.89 per) just to try them out, they work just fine so far and supposedly they are 100k plugs. I will change them before then, I am sure.

Got those, cap, rotor, Bosch Premium plug wires, anti-seize grease for the threads and dielectric grease for the boots for around $71 a couple weeks ago. Might be even better cheaper this week.

 

I live in Ca and the last time I had my 88 smogged it failed as a gross polluters,I did all the right things to pass, but a bad o2 sensor screwed that up. With talkin to the smog guy he said that any missing or rough running would be almost a sure fail.fresh oil and test All sensor ,and inspect the vapor recovery systems,that is a separate test that older car have to pass ,good luck on the smog test

 

I have never had champion plugs, I think their quality has decreased over the years, I like to run Autolite and AC delco platinums, whatever you do, DONT run those bosch ones with multiple ground prongs or even the single platinums because they have a very small ground pin

 

ive used the seafoam before and i like it, planning on running the champion copper plugs, clean the cap and rotor if i dont replace them

lookin at the oxygen sensor but trying to do this on a very tight buget at the moment

how do/can you tell if the sensor is bad before smogging it?

thinking about putting in a fuel treatment aswell, the gas is about a month old im told

 

Move to alabama.......HAHA just kidding how offten do you guys have to have this test done on your cars .....Side not something like 60% of the bad ozone crap comes all the way across the pacific from china ......how bout instead of spending money testing your cars over there lets just build a big *** dome over china ......that would be one big dome haahahaha ......any way enough with the crap I changed my injectors on my renix to the yellow ford #19 ones and it now runs like a dream no miss or stumbling I could not belive the differance and I got 8 off ebay tested with new orings for like $60...just a thought

 

I used to live in CA and have gotten plenty of vehicles that shouldn't pass smog to pass easily.

Here is the trick: The test measures levels in percentages. If you throw off the percentages, no matter how much crap is comming out your exhaust, you can still have a low percentage (by boosting the levels of the other readings). Put three bottles of octane booster in your gas tank. Then drive your car really hard to heat up the cattalitic converter as hot as you can get it. Then take it to a 15 min smog place or somewhere that guarantees to get your car in there before it cools down. The extra octane and the burning hot cat will throw off the percentage readings enough to allow a "pass".

Hope this helps.
though, if you are misfiring, you should get a tune up anyway because you really want all your cylinders hitting.

 

I would try Lucas fuel treatment, I did 3 tanks of that, My engine ran alot better, i replaced the O2 and it passed with ease, the first test was really bad, I went to the smog shop on Wible Rd, by Rainbow carwash, he is a really good guy, helped me out alot

 

Testing O2 sensors that are installed

The engine must first be fully warm. If you have a defective thermostat, this test may not be possible due to a minimum temperature required for closed loop operation. Attach the positive lead of a high impedence DC voltmeter to the Oxygen sensor output wire. This wire should remain attached to the computer. You will have to back probe the connection or use a jumper wire to get access. The negative lead should be attached to a good clean ground on the engine block or accessory bracket. Cheap voltmeters will not give accurate results because they load down the circuit and absorb the voltage that they are attempting to measure. A acceptable value is 1,000,000 ohms/volt or more on the DC voltage. Most (if not all) digital voltmeters meet this need. Few (if any) non-powered analog (needle style) voltmeters do. Check the specs for your meter to find out. Set your meter to look for 1 volt DC. Many late model cars use a heated O2 sensor. These have either two or three wires instead of one. Heated sensors will have 12 volts on one lead, ground on the other, and the sensor signal on the third. If you have two or three wires, use a 15 or higher volt scale on the meter until you know which is the sensor output wire. When you turn the key on, do not start the engine. You should see a change in voltage on the meter in most late model cars. If not, check your connections. Next, check your leads to make sure you won't wrap up any wires in the belts, etc. then start the engine. You should run the engine above 2000 rpm for two minutes to warm the O2 sensor and try to get into closed loop. Closed loop operation is indicated by the sensor showing several cross counts per second. It may help to rev the engine between idle and about 3000 rpm several times. The computer recognizes the sensor as hot and active once there are several cross counts. You are looking for voltage to go above and below 0.45 volts. If you see less than 0.2 and more than 0.7 volts and the value changes rapidly, you are through, your sensor is good. If not, is it steady high (> 0.45) near 0.45 or steady low (< 0.45). If the voltage is near the middle, you may not be hot yet. Run the engine above 2000 rpm again. If the reading is steady low, add richness by partially closing the choke or adding some propane through the air intake. Be very careful if you work with any extra gasoline, you can easily be burned or have an explosion. If the voltage now rises above 0.7 to 0.9, and you can change it at will by changing the extra fuel, the O2 sensor is usually good. If the voltage is steady high, create a vacuum leak. Try pulling the PCV valve out of it's hose and letting air enter. You can also use the power brake vacuum supply hose. If this drives the voltage to 0.2 to 0.3 or less and you can control it at will by opening and closing the vacuum leak, the sensor is usually good. If you are not able to make a change either way, stop the engine, unhook the sensor wire from the computer harness, and reattach your voltmeter to the sensor output wire. Repeat the rich and lean steps. If you can't get the sensor voltage to change, and you have a good sensor and ground connection, try heating it once more. Repeat the rich and lean steps. If still no voltage or fixed voltage, you have a bad sensor. If you are not getting a voltage and the car has been running rich lately, the sensor may be carbon fouled. It is sometimes possible to clean a sensor in the car. Do this by unplugging the sensor harness, warming up the engine, and creating a lean condition at about 2000 rpm for 1 or 2 minutes. Create a big enough vacuum leak so that the engine begins to slow down. The extra heat will clean it off if possible. If not, it was dead anyway, no loss. In either case, fix the cause of the rich mixture and retest. If you don't, the new sensor will fail. Testing O2 sensors on the workbench.

Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

 

Check for any vacuum leaks. Check your EGR valve. Change your O2 sensor. Getting mine straightened out was a HUGE *****.

 

thanks mitchell205 - i printed out that write-up so i will read it over and give it a try when i can


now i remember why i like smog exempt vehicles, lol

thanks for the help guys

 

random question - what kind of coolant goes in it? just regular green antifreeze or something else?