So i bought i 1990 Cherokee Limited about a week ago. It runs ok but i took it to get the emissions done and it failed. I knew it was gonna fail but i wanted to know where it would fail before i start putting money into it to try and get it to pass.

I plan on doing a tune up ya know spark plugs, wires, air filter, oil change, distributor cap, and also change out the o2 sensor. i dont think the check engine light works so i cant use that to determine whats wrong so im just gonna change what i can to try and get it to pass.

Before I change all that out tho I wanted to run seafoam through the whole thing first and this is where my questions come in.

Is there a certian amount of time i need to wait to get my car retested after using seafoam?

I know they say use 1oz of seafoam per gallon of gas but how much gas should I have in the tank when I use it?

ive only seen one person address this and they said use half a tank of gas so is that correct?

If there is still seafoam in the system is it going to automatically make me fail the emissions again?

Any help would be great. i want to get this fixed and tested as soon as possible so i can use my free test lol.

 

I dumped the whole 16oz can in the tank when I had half a tank and it was fine and half in the crankcase and it works fine now just get an oild change after like 100-200 miles I looked into it and called the sea foam place because I was questioning it a lot haha but its great

 

First thing i am not sure if seafoam will make u fail a smog test. but what i do know is that if your check engine light doesnt work that isnt a big deal just take your vehicle to an autoparts store and have them hook up a scanner and see if it throws any codes. If it does then fix what needs be. After that then disconnect your battery for 10 min and it will normally clear the code. i do say normally. there are those certain times it wont. The second thing is just a suggestion. Seafoam acts as an oil slick on top of gas. So when you do put seafoam in do it before you put gas in the tank to insure that it is mixed well with the fuel. Sorry i couldnt help with the emission. I am from nebraska and i dont have to worry about it there.

 

thanks, this is where im also having questions because i cant drive the car around to much. i mean i have insurance on it but no tag and i cant get the tag until is passes emissions and where i live the cops will give you a ticket whenever they can so i dont want to drive it to much.

is it a problem if I change the oil before driving it 100 miles?

 

lol i cant believe i didnt even think of that.

your lucky you dont have emissions. sadly i bought the car from a guy about 30 miles from me and where he lives he doesnt need emissions but where i live i do need it. honesly makes no sense to me that he can be that close and he doesnt have to have it but I do.

 

I'm not a betting man, but I will bet $100 your 1990 will NOT throw a code or find where to hook up scanner.

Seriously, there are no "codes" for 87-90 renix, i'm sure cruiser54 will chime in on this. As for passing emissions, your on the right track, new O2 sensor, clean the MAP sensor. Any driving issues, missing etc? Catalytic Converter installed? If not Install one ASAP. when you go to have the test done, make sure its hot, don't drive straight there, drive at least 45mins-1hr before going.

 

I dont think so i mean its just cleaning everything out so the oil will be super dirty when you do change it.. there will be lots of smoke from your exhaust because of all the **** that is being burnt off.. I dont see why it would matter if its less then 100 miles just run it hard so it gets through to everything and cleans it out you know

 

I didn't notice what state you live in. Here in Colorado, you can get a temp.tag when you purchase a new vehicle, which is good for about 45 days. During this time you can do maintenance, get inspections, etc, etc. Then just take the test results in to the DMV to get your permanent plates. Again, my only experience being Colorado, the state puts a max dollar amount that you have to spend to try to get your vehicle to pass the test. At that point, if it still doesn't pass, you still get your plates.

Re: Seafoam. I bought a 2001 Sport, 4.0l, manual trans just before Christmas. I ran a can of Seafoan through the tank, and about 3 days later got a solid CEL. Everything else was OK, so I drove it home and took it to the dealership the next day. They said it threw an emissions code, needed new O2 sensor and cats. Well it had already passed emissions a few weeks earlier, so I figured I would just live with it. About two days later, the CEL went out and hasn't come back on since. I'm assuming it's from the Seafoam cleaning out the gunk in the engine, which fouled the sensor. Eventually the sensor started working again, and life was good.

Good luck with yours.

 

Your jeep HAS NO check engine light. The OBD system (do I dare call it that?) does not throw codes. If you can find a guy with a snap on scanner it will only give you the freeze frame data. BTW One of those scanners cost $3000 if you're wondering

 

Which part of the emissions did you fail on? HC or CO? I do safety and emissions here in Utah, maybe I could try to help you.

 

ha well that clears that up. the last jeep i had was a 1996 so i wasnt sure. i decided against even taking it anywhere to see if someone could scan it because i know a lot needs to be replaced on it anyways so I figured whats the point. im gonna change it anyways.

 

Ha i failed HC and CO but I passed NO. any help you could give me would be great.

 

I live in GA. as far as i know all we have is 30 days from the day of purchase to tag and title the car. after those thirty days there is like an extra fee you have to pay when you finally do go to get th tags.

 

The car drives fine. it has started up every time i hve gone to start it. the day i bought the car i had a 40 mile ride down the highway to get home and the car made it with no problem. didnt over heat, never lost power/ never had lack of power.

 

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