Failed CA smog due to high HC @ idle....advice?

[Blackstar8507]

smog report attached.

[4.3LXJ]

Crap, after all the work. Did the technician make any suggestions? Such as worn out cat etc?

[Blackstar8507]

NO. I asked about the cat and he said he could diag it for $130...or I could some how check the temp of the exhaust before/after the cat. He said it should be cooler in and hotter out.

OR possibly a timing issue.

[whowey]

Normally a high HC level means that there is excess unburnt fuel in the air stream. Start by checking all the usual culprits. Injector O-rings, making sure that you don't have an injector sticking open.

Also did you get the engine good and hot before going to test? That can sometimes clean up any unburnt fuel in the engine.

[4.3LXJ]

One trick I always use is to run premium gas during the smog. It burns cleaner and sometimes will take care of a close situation. It is the ethanol. Makes it burn dirty

[Blackstar8507]

It was good and hot. The tech actually said it started to over heat at the end. I blame the ventilation in the shop. Considering I drove it up to Magalia and back straight to the shop w/o the temp going over 200*. I am going to check the timing (Steve do you have a gun?) and seafoam it on my trip to the coast. I don't have time to test again until I get back.

[4.3LXJ]

Yes, I have a timing light

[Blackstar8507]

i'll be in your area thursday. Maybe I could come by?

[whowey]

It is the ethanol. Makes it burn dirty

No ethanol would not be the culprit.

Ethanol blended fuels will show lower levels of hydrocarbons than non ethanol fuels will.

http://www.cleanairchoice.org/fuels/E85C02Report2004.PDF

There is a chart on the top of page 4 showing that increasing the amounts of ethanol in fuel will result in lower HC levels using the EPA 'hot-start' testing. Which is pretty close to what sniffer testing is.

[4.3LXJ]

No ethanol would not be the culprit.

Ethanol blended fuels will show lower levels of hydrocarbons than non ethanol fuels will.

Better read that again. That is for an E85 equipped vehicle. Our injectors and combustion chambers are designed for gasoline. When our local gas blends go from summer to winter blend with increased ethanol, we with our non E85 vehicles take a 25% hit in milage and horsepower. Cat gets nice and hot though. The physical chemistry behind this is that the alcohol forms tighter hydrogen bonds to gasoline molecules than gasoline molecules to themselves. This makes less atomization and will increase emissions, mostly HC and there will be a loss of power and milage greater than the amount of BTUs lost by the lesser BTUs of ethanol itself. Consequently, If I want to get my usual 16 mpg instead of 10 mpg, I pay an extra twenty cents a gallon. And this is not just Jeeps. It works across the board here in sunny CA. It is just a fact that our milage goes up by 20% in neighboring states. Also, the premium trick is what some smog guys use to make marginal vehicles pass

[Brasscatz]

NO. I asked about the cat and he said he could diag it for $130...or I could some how check the temp of the exhaust before/after the cat. He said it should be cooler in and hotter out.

OR possibly a timing issue.

$130 for a diagnosis??? You could get a new cat for cheaper than that!!

[Blackstar8507]

Any suggestions on a high flow cat?

[4.3LXJ]

Summit Racing has good prices and selections

[whowey]

I've been doing a crap ton of reading the last few days on California winter blends of fuel. Because the idea that CA specs MORE oxygenate in fuels in the winter when the norm is less, had me confused.

But.. I did find something interesting that would lead to the OPs problem. California allows a much higher level of Butane in winter fuels to reduce cost. This butane would cause a higher level of HC in the sniffer test. Increased butane levels don't seem to be prevalent in premium fuel. This would lead to people running premium fuel seeing the lower HC levels.

[4.3LXJ]

Thank you, that is what I have been saying. Use premium fuels to smog

[ParadiseXJ]

I am going to check the timing

Could you explain how to adjust the timing on a 94 XJ?

...and for $130 I'd be happy to diagnose your CAT. :bsflag:
What shop was that?? There is a "pass or free shop" on Clark Rd. in P'dise.

Take a look at it at night...all warmed up. If it's glowing...it's going. If you tap it with a rubber/wood mallet, and it rattles, it's shot.

Cash? or charge? JK