I have an '85 CJ7, Good little red jeep. It fails the low speed emissions test here in Texas... any thoughts on what can be done to get it to pass? John

Which test is it failing?  Which county are you in?

 

Roger in El Paso

 

The CO emissions and the unbirned gas one... ( cannot remember the official name) My research turns up that I might need to lean the mixture... this car passed the last time it was inspected in it's current configuration.... Any help would be great... thanks

I have my Jeep set a little lean give it a tune up and always bring a new gas cap with me to the test as I always need to replace it. Passes every time with the new gas cap.   Paul   79 CJ-7, 258, Auto with Quadratrac (O|||||O)

I have heard people trying some alcohol from Walgreens in the gas tank.   I never tried it but several people on Jeep lists have claimed it worked for them.

There is just something about putting Isopropyl Alcohol in my gas tank.....

I always bring a new gas cap, as they want to sell you the new $5 cap for $15, and wont let me keep my key cap.
Now that I have swapped a 4.0 in, it wont run well enough to get to the smog station. BAR first

It idles fine, but when you use the accelerator, it starts bogging and such.
30 psi on the fuel rail
Hesco TPS on the dampener
tried affecting the phase of the distributor

Dan

Paul

Try leaning out the idle mixture.  Also you can let the tank go almost dry and put in  a couple of gallons of premium grade gas for the test.

You still have three years of tests to pass, so hang in there with it.

 

Roger

 

HC - hydrocarbons - is the emission of unburned fuel. It's indicative of a misfire. CO - carbon monoxide - indicates a rich air/fuel mixture. At the shop where I work we have a standard treatment for emissions failures. First we spray a whole can of carb cleaner into the intake to clean it up REALLY GOOD. We do this with the engine running. Second, we change the oil and filter. Third, if the spark plugs aren't BRAND NEW, we change them. We ohm the wires, if any one is out of range, we change all of them. If applicable, we change the distributor cap, rotor and points,(if it uses points). If the coil doesn't put out a high enough spark, we change it. If the vehicle has an O2 sensor, we change it. If the air filter isn't BRAND NEW, we change it. We check the timing. If the vehicle is carburetted, we lean it. We check the gas cap, if it's loose we replace it. We check the PCV and EGR systems and replace any suspect parts. We have a 100% pass rate for re-tests. mtm

If you are trying to raise the octane, xylene and tolulene are what the refineries used to use. Tolulene is available at about $6 for a 8 oz bottle on ebay or $10 a gallon at a chemical supply store. It has an octane of about 120, so 8-12 oz in a full tank raises your octane a few points. Racers who are too cheap to buy racing fuel still use it...rumors have it that it can dry out some seals. But it is just an aromic petro distillate. Da stuff that makes gas burn, and da stuff that evaporates. Isoproprial Alcohol is contaminated alcohol (so you cannot drink it and so you dont have to pay an alcohol tax) I would go with denatured alcohol from the hardware store paint section if you are going to do that...but are you not only making gasahol. In Cali we have gasahol in the summer. 10% by volume. They add 10% alcohol to the gas, it lowers my prius gas miledge by 10%. So they just get to charge me for a gallon and give me 90% of a gallon of gas. Ebay will give you lots of information on tolulene and such...and I have a few gallons in my backyard for sale or trade.... Dan

Good to hear all of this and appreciate the reply... I just did all of this to my jeep last night; plugs, oil, pcv, air filter. and leaned as much as I could then went a little more... .... fingers crossed!

Isopropyl is a completely different molecule from ethanol.

 

Roger

 

Good news.. it passed. Thanks for all the advice! John

I sucked in College Chemistry anyways....

I hope the ph was close to 7

 

Roger