Honda failed CA emissions... any advice?

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The misfire needs to be diagnosed and fixed. Otherwise, your numbers are never going to be improved. You will need to find an equivalent ScannerDanner type of person in your area! (ref: youtube)
 
Seems like a mental check back over on the basics needs to be in order: Ignition/spark delivery, fuel, air...and of course mechanical however it is running.

A recent oil change? Fuel pressure test? Sounds ignition or electrical related, possibly. You have the OE plugs in, etc, no CEL codes?
 
teambeechstreet,

Have you ever replaced the ignition coil?
I read that you replaced the plugs, wires, cap and rotor, and even the distributor, but I don't think I saw you mention that you replaced the ignition coils.

BC.
 
Originally Posted By: ltslimjim
Seems like a mental check back over on the basics needs to be in order: Ignition/spark delivery, fuel, air...and of course mechanical however it is running.

A recent oil change? Fuel pressure test? Sounds ignition or electrical related, possibly. You have the OE plugs in, etc, no CEL codes?


I have not done a fuel pressure test, which is on my to-do list at the moment. All sensors, plugs, etc are OEM. No CEL codes at all.

Originally Posted By: Bladecutter
teambeechstreet,

Have you ever replaced the ignition coil?
I read that you replaced the plugs, wires, cap and rotor, and even the distributor, but I don't think I saw you mention that you replaced the ignition coils.

BC.


The ignition coil is inside the distributor and was replaced when I installed the new distributor. Thanks though.
 
Go rent a compression test tool and see how's your compression number and compare against the spec of the engine, and the difference between the cylinder. You may have head gasket problem or stuck ring if your numbers are off.

When you replace the plugs, did your old plugs have a green (or whatever the coolant color looks like) tint on it?

You might also want to borrow a tool (not sure what kind) that can read the misfire number on each cylinder and pinpoint where is the misfire from.
 
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Originally Posted By: PandaBear
Go rent a compression test tool and see how's your compression number and compare against the spec of the engine, and the difference between the cylinder. You may have head gasket problem or stuck ring if your numbers are off.

When you replace the plugs, did your old plugs have a green (or whatever the coolant color looks like) tint on it?

You might also want to borrow a tool (not sure what kind) that can read the misfire number on each cylinder and pinpoint where is the misfire from.


Hi, thanks for the suggestions. I did a compression test several days ago and the numbers were 160 across the board. Nominal is 180 and minimum is 135, so compression seems OK for a 250K motor. There are no signs of coolant loss and I have never seen coolant inside the cylinders or on the spark plugs. I haven't heard of a tool that pinpoints which cylinder the misfire is coming from. I may have to look into this.
 
Finally got it to pass smog and figured out why HCs were through the roof.

The OEM exhaust manifold on this car was cracked when I bought it, so I thought I'd replace it with a cheap aftermarket piece. Something I never noticed was the aftermarket unit had the oxygen sensor bung in only one runner. So the oxygen sensor was only reading exhaust gases from one cylinder instead of all four like the OEM unit. Ghetto fixed the crack on the OEM piece and slapped it back on. Presto! HCs were back to normal! Car passed smog no problem!!! Weird thing is the gas mileage has decreased considerably. I was averaging 32-33 mpg regularly and now it is getting 27-28 mpg. Oh well, no more smog headaches. Just my luck though, the radio and A/C decided to take a dive a couple days later. If it's not one thing, it's another. Thanks for everyone's help!
 
I'm curious as to how you arrived at this conclusion? While obviously it was the cause of your trouble, it seems pretty unlikely.
 
Originally Posted By: The_Eric
I'm curious as to how you arrived at this conclusion? While obviously it was the cause of your trouble, it seems pretty unlikely.

I stumbled upon a thread on a Honda-specific forum where a guy with the same car/engine swapped the exhaust manifold to the same aftermarket one I was using. He also failed smog for really high HC and someone else told him that it was because of the placement of oxygen sensor on only one runner. The sensor was reading lean and telling the ECU to dump more fuel. The thread starter posted up that he switched back to his OEM manifold and passed smog.
 
Is it because this aftermarket header is leaking? or is it because having the O2 on 1 runner makes it response slower and fluctuate more than having it read the exhaust on all 4? One thing for sure is this placement will make the O2 heat up more slowly.

Can you ask for a refund from the manufacturer or retailer?
 
You may have a fuel distribution problem where the individual cylinders are not seeing the same air fuel ratio. An extremely filthy intake, or more likely a leaky intake gasket could cause this as could an excessively worn cam. With the OE exhaust manifold the O2S is getting a better representation of average mix. If this is so you have one or more cylinders running rich and one or more running lean. This should give you poorer fuel efficiency and power, but thanks to the catalytic converter, emissions are good enough to pass the test.
 
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