Intake gas filter

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JDNightFox
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Intake gas filter

Post by JDNightFox »

I'm tracing my distributor advance vacuum issues and this seems to be where the vacuum should be coming from. What is this and where can I buy a new one?

It's labeled as the "gas filter" on the diagrams and it's just a two port vacuum opening on cylinder #1

I have yet to find anywhere in the FSM where it shows you how to test if it's functioning correctly
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NWMO
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Re: Intake gas filter

Post by NWMO »

Hey NightFox,

FSM pages 18-21 cover the "gas filter", which you describe well as a two port vacuum location on the #1 intake manifold. It looks to me like it has no "function", but simply provides vacuum from #1 intake manifold to facilitate the "mixture control" valve (which provides fresh air during abrupt deceleration) and the second port ties into the tvsv for EGR control.

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

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JDNightFox
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Re: Intake gas filter

Post by JDNightFox »

My car is Cali compliant, so one side of it controls the distributor advance, and the other side controls the choke-open feature

I have just finished removing it and testing with a vacuum pump and it has very poor suction ability. This may be the cause of both my timing issue and the poor gas mileage (because maybe the choke has been stuck partially closed for some time)

Which pages are you referring to? EM 18-21 have it showing but not how to test it
JDNightFox
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Re: Intake gas filter

Post by JDNightFox »

I also found that it is leaking around the seal. I need to know if it is designed to restrict vacuum or if I can just drill a hole through the middle to open it up
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NWMO
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Re: Intake gas filter

Post by NWMO »

I assume this is the part we are talking about? If so, I would clean with a “plastic safe” solvent, not drill. As I shine the light down the intake side, it appears the plastic base includes a porous media to allow air flow, but likely slow down the fuel in the mixed air? Regardless of which of the three ports I plug, I can blow air through the remaining two that are open.

I don’t expect it is designed to restrict (though it may some). I believe it is simply a port to pull intake vacuum for control to two different systems. Any leaks in or at the fitting would create lower vac and interfere with the other systems control.

Chris
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
JDNightFox
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Re: Intake gas filter

Post by JDNightFox »

Okay so in that one there is no air restriction when you blow air through it?
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NWMO
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Re: Intake gas filter

Post by NWMO »

Nothing signicant, air moves through at a reasonable clip. The flow between the top two ports should be completely unencumbered, you might notice a little restriction when blowing through the bottom port.
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
JDNightFox
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Re: Intake gas filter

Post by JDNightFox »

yes the top two are open, but going through the bottom it has a heavy restriction on it. I'll try to clean it out with carb cleaner
JDNightFox
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Re: Intake gas filter

Post by JDNightFox »

Okay the carb cleaner worked really good to clean it out. It has much better flow through it and I put the engine back together, my timing now advances from 13 degrees to 15/16 at idle and the car actually starts easily. Hahaha

Verified that my TVSV works now by letting the engine warm up and watching the choke break engage to open the choke

Unfortunately I broke one of the tabs off the gas filter when installing it so now I have to disassemble it again tomorrow and put epoxy on it

Now I need to figure out how to adjust the idle because it’s idling really high (after fixing all these vacuum leaks)

The shop that charged my AC adjusted the idle as is when it came in before
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NWMO
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Re: Intake gas filter

Post by NWMO »

Good job,

I’ll clean mine up before installing.

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
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Petros
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Re: Intake gas filter

Post by Petros »

it is just a vacuum port, it is a "gas filter" in the sense that some foam or screen inside prevents fuel from the intake manifold from getting up into the vacuum system. though vac from into the manifold, a back fire could send fuel up the vac lines.

A good cleaning is all it should need.
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JDNightFox
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Joined: Sun Nov 01, 2015 5:39 pm
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Re: Intake gas filter

Post by JDNightFox »

NWMO wrote: Thu Dec 20, 2018 9:08 pm Good job,

I’ll clean mine up before installing.

Chris
Make sure to test if yours is leaking too. I wouldn't have known that it was leaking around the seal if I didn't pull it off and plug 2 of the openings. Putting epoxy around the metal/plastic gap fixed it
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