Failed smog inspection! Help! (please)

[Traveler111]

I posted this question earlier in my "rebuild 360" topic but it got too long etc.

Here's the thing. I just bought an '88 G.W.

It has new plugs. Wires look like new. so does cap and rotor. Coil is new. Oil has been changed.

It idles very high. When you put it in Drive, it gets very rough but smoothes out when going down the road. There is one ticking valve tappet. I put Hydra Valve Clean (sp?) in it but so far, it's still ticking. It's not clacking, just ticking.

Cat looks OK from the outside.

Here are the numbers from the NJ inspection:

HC = 171, max allowed is 159 - Failed
NOx = 429, max allowed is 1624 - Passed
CO% = 2.86, max is 1.42 - Failed

Any suggestions would sure be appreciated.

[Traveler111]

Forgot to mention that this beast has 130,000 miles on it.

[JeepKahn]

Check your timing and for vacuum leaks is the best place to start... I'd also check the carb, sounds like you could have a float set too high allowing gas overflow but at speed its drawing enough to not overfill the bowl...How many miles are on the catastrophic converter, when they go bad it's not normally externally visible... It's more about miles that causes them to funk up...

[Stuka]

I would also pull your plugs and have a looksy, make sure your not burning any oil. Those HC's are tripple what my 75 cherokee had with no cat (didnt come with one) with 155k on it (how much it had when i bought it). Thise will also say if your running rich or not. Also check your vacuum, bad idle can also mean vacuum leak.

[Traveler111]

I changed the plugs before inspection. There was no oil. One plug had some dry carbon. The others were burning well with just a little more gap than they should have.

As far as I can tell, all the vacuum lines are connected and don't seem to be cracked. Will inspect more carefully.

[Booger]

This is probably not true, but I heard that if you empty your tank most of the way and use exxon 93 or 94 you will get better results, but like i said it probably isn't true.

[Traveler111]

Nope. Don't believe it. High octane is just to prevent knocking in high compression engines. It has no other benefit.

[mtn goat]

if you cant find any vac leaks, consider resetting your carb...you didnt say if you had to do idle and speed tests, but you need to lean down you mixture a bit...this may produce more NOx's but you have some room int that catagory...A place to start is to find where the mixture where the motor idles best and then lean out until you drop about 50 rpms

[Traveler111]

I forgot to mention that this NJ test is done at speed on a dyno. Idle settings probably won't be enough, I guess.

[brielly]

If all else fails try a private inspection station. They don't use a dyno to test which should make it easier to pass. Mine cost me $60 and was well worth it. They just leaned out the carb and got it through.

[letank]

High HC and CO.. seems like the power valve is gone or disconnected..... the one under the carb with a vaccum line.... if you pull the vacuum line and gas comes out... then you have a leaky power valve

of course a high float would do it as well

Michel