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Old 08-23-2010, 09:47 AM   #21
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Re: Installed new carb insulator= slightly higher idle?

When I suspect a vacuum leak on a carb'd car w/ automatic transmission, I look to see how much the RPMs drop when I put the car in gear.

For instance, my Buick used to idle at 900 in park/neutral, then 750 in gear. That's a 150RPM drop.

When I have a vacuum leak, that changes by more like 300 RPM.

By the way your engine speed is oscillating, however, I have to suspect your ignition. Did you hook the vacuum advance and transmission signal back to the correct ports? (One is ported vacuum, one is unported vacuum)

-BC
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Old 08-23-2010, 04:53 PM   #22
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Re: Installed new carb insulator= slightly higher idle?

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Originally Posted by bobc455 View Post
When I suspect a vacuum leak on a carb'd car w/ automatic transmission, I look to see how much the RPMs drop when I put the car in gear.

For instance, my Buick used to idle at 900 in park/neutral, then 750 in gear. That's a 150RPM drop.

When I have a vacuum leak, that changes by more like 300 RPM.

By the way your engine speed is oscillating, however, I have to suspect your ignition. Did you hook the vacuum advance and transmission signal back to the correct ports? (One is ported vacuum, one is unported vacuum)

-BC
Does this apply to a manual transmission?
I'm going to check the timing advance ports next.
At the moment I'm working on the O2 sensor. It seems it wont thread in!!!!
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Old 08-23-2010, 04:54 PM   #23
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Re: Installed new carb insulator= slightly higher idle?

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Originally Posted by Jay2TheRescue View Post
I know what the problem is... Signatures are not available until you reach Junior Member. Once you have been a member for 30 days, and have a post count over 25 it will be available in your control panel. You also need to add your vehicles to your garage tab, and enter some fillups.

Once you have your vehicles in your garage, I may be able to manually add your vehicle's tag to a signature from the admin control panel.
Ok. I'll keep typing until I get 25 posts......
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Old 08-23-2010, 05:03 PM   #24
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Re: Installed new carb insulator= slightly higher idle?

Get garage entries for your vehicles, and I may be able to add your vehicle tag to a signature for you. We can make an exception for someone's vehicle tag. The reason new members can't have signatures is because we were getting people join and post once or twice, then add spam to their signature.

Let me know once you've added your vehicles to the garage and I'll see what I can do on the admin side to add it as a signature for you.
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Old 08-23-2010, 06:16 PM   #25
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Thumbs up Re: Installed new carb insulator= slightly higher idle?

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Originally Posted by Jay2TheRescue View Post
Get garage entries for your vehicles, and I may be able to add your vehicle tag to a signature for you. We can make an exception for someone's vehicle tag. The reason new members can't have signatures is because we were getting people join and post once or twice, then add spam to their signature.

Let me know once you've added your vehicles to the garage and I'll see what I can do on the admin side to add it as a signature for you.
Thanks! I'll let you know.
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Old 08-23-2010, 06:58 PM   #26
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Re: Installed new carb insulator= slightly higher idle?

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Originally Posted by Erik View Post
The best you can do is monitor the oxygen sensor output with a digital voltmeter and see if it averages out to 400-500 milivolts (it normally jumps around above and below these values as the air bleeds try to lean it out when it gets too rich).

You can get a universal 1 wire oxygen sensor for it at many auto parts stores and splice it into the factory wire using the materials included with the sensor (heat shrink tubing is included with the sensor)- So you just cut the wire/connector off the old sensor and add it to the new one.

The fuel injected civics/crx's of the 1984-1987 generation do have a computer that stores codes that can be retrieved.

If you have air conditioning, there is a vacuum operated idle up mechanism that bumps you up to a fast idle when the AC compressor kicks on. It is on the drivers side of the carb, toward the back. It may be bumping up your idle.


Also check the fuel level in the carb- if the float level is changing because of a bad float valve, the idle speed will change too. You can check the fuel level by looking through the sight glass on the drivers side of the carb while the engine is running.
The O2 sensor seems low if reading below 2k rpm and a bit high 2500rpm. Not sure if I did it correctly but it was good and warm.
I think I'll just pop the universal unit in and roll the dice.
BTW the OEM O2 sensor was $215

The fuel level was at the upper area of the sight glass, with only a small amount of air visible.
Did i read somewhere that the fuel needed to be between the two points in the center?
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Old 08-23-2010, 07:29 PM   #27
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Re: Installed new carb insulator= slightly higher idle?

It should be in the dead center of the glass- maybe that is your issue.

It is easy to adjust the fuel level- just turn the screw on the top of the carb (next to where the gas line attaches) in very slowly- it will take some time to see the gas level go down because the engine must burn it.
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Old 08-24-2010, 04:06 AM   #28
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Re: Installed new carb insulator= slightly higher idle?

That screw has the factory paint on it, that's what's confusing.

I'm getting a thread chaser for my o2 sensor, then look for the vacuum leaks.
after that I'll do the fuel level.
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Old 08-24-2010, 05:42 AM   #29
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Re: Installed new carb insulator= slightly higher idle?

Yeah- its just painted on lock tight. Don't be afraid to break it loose and adjust it slowly.
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Old 08-24-2010, 06:04 PM   #30
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Re: Installed new carb insulator= slightly higher idle?

The O2 sensor is on and started looking for vacuum leaks and I think I found one on the vacuum advance. There are two ports and only one holds vacuum.
I read somewhere that this is common to leak.
Can anyone explain how these two ports work? I'm guessing each is set for a different carburetor port. So to give more advancement when that hugebutterfly fully opens.

I'll order another one and then reset the idle. I'm still going to check for vacuum leaks around the carb after I get this part on.

Any words of wisdom with the removing/installation of this particular part?
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