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89 YJ failed smog!

Hello All,

My 89 4.2L YJ just failed its smog on HC, results as follows...

15mph MAX 124 AVG 34 MEASURE 125 25mph MAX 104 AVG 23 MEASURE 104

As you can see it was a real close one, it was well below average on CO and NO.

I should have put two and two together as I noticed the other day some soot build-up on the tail pipe. SO my question is beyond changing the PCV valve, an oil change, and high octane gas, is there anything else I can do? I changed the PCV valve, distributor cap, rotor and ignition wires three months ago, do you think changing the sparks would help any?

Thank you in advance for your time and consideration of this matter and your replies.

Cheers, kind regards, Steve

Reply to
Stevil
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Steve,

High octane gas burns slower and colder than the gasoline you are supposed to be using therefore creating more pollution (especially hydrocarbons).

Make sure you run the vehicle hard before the test so the engine is fully heated up.

It probably wouldn't hurt to run a can of Techron, BG44, SeaFoam, or Berrymans into that tank of high-test you have there, just make sure you run that tank as close to empty as you dare before refilling it with regular.

You may want to get a can of GumOut Jet Spray and give the carb a thorough cleaning.

New sparkplugs are probably not necessary but it wouldn't hurt to pull them and give then a good look to see it there is any indication of a misfire.

Let us know..

Reply to
billy ray

I failed emissions in my Toyota recently. I got a bottle of "Garunteed to pass" emissions formula. I added it with a full tank of gas and ran in nearly empty, then I added another bottle and went for a 20 mile hard drive before going directly to the emissions station.

Passed with flying colors.

HTH

Carl

Reply to
Carl

Some soot on the tail pipe is pretty much normal on a vehicle with a cat converter. If there was a lot of it, that would indicate it's running rich, but if your CO readings were low, it's not rich. High octane gas might help a little with high NOx, but won't do a thing for HC.

HC is unburned fuel. Anything that can cause a misfire could cause this. Ignition problems, or a lean mixture would be what I'd look for first. Make sure the timing is where it belongs. Could also be a dead cat or air injection system.

Reply to
bllsht

"Stevil"

Along with the misfire idea, change the spark plugs. If the air injection system is sub-standard, that would give you a point or two on the HC too. On a vehicle this old, often the pump seizes up and someone puts plugs in the holes for the AIR nozzles.

Earle

Reply to
Earle Horton

A clean air filter does wonders for HC emissions, so does new plugs....

I would also recommend you check the new distributor cap and rotor out. There are a bad batch of them out on store shelves. The rotors are too short and start arcing out very soon after installing them.

High octane might help smooth things out if it sputters at idle. Your engine calls for high test if running hot and loaded to avoid engine ping.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

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