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> L-jet question on my'74
ricardo
post Nov 19 2016, 02:45 PM
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Got my car running recently and I have a few problems.
It seems that the car runs if I disconnect the decel valve hose that goes to the air sensor.
If I close of the opening at the air sensor, the car stalls.
My thinking is the car is only running because its getting air through the hose opening, and not through air sensor.

I tested the air sensor terminals as per the Haynes manual and got the following:

Terminal 6 and 9 284 ohms Range 200 to 400
Terminal 7 and 8 153 ohms Range 120 to 400

Anyone have any idea whats going on?
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TheCabinetmaker
post Nov 19 2016, 02:48 PM
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Don't you already have a thread on this topic? Why post two?
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ricardo
post Nov 21 2016, 09:26 AM
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QUOTE(ricardo @ Nov 19 2016, 03:45 PM) *

Got my car running recently and I have a few problems.
It seems that the car runs if I disconnect the decel valve hose that goes to the air sensor.
If I close of the opening at the air sensor, the car stalls.
My thinking is the car is only running because its getting air through the hose opening, and not through air sensor.

I tested the air sensor terminals as per the Haynes manual and got the following:

Terminal 6 and 9 284 ohms Range 200 to 400
Terminal 7 and 8 153 ohms Range 120 to 400

Anyone have any idea whats going on?



Somebody know what's going on?
Anybody?
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malcolm2
post Nov 21 2016, 10:29 AM
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OEM vacuum layout.
Attached Image


I took my DECEL valve out and have this.... I folded the OLIVE hose over and plugged it. Now mine looks like this.... I am not use I follow your problem. What is an air sensor? Is it in either layout?

Attached Image
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Dave_Darling
post Nov 21 2016, 10:33 AM
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You can check if air is going into the engine--just put your hand over the intake snorkel. You should feel the air getting drawn in.

Unplugging one of the hoses that is "downstream" of the air-flow meter will give you a lean mixture. Air that gets drawn in through that open hose (or the open fitting the hose had been plugged into, as in this case) is not measured by the AFM so the FI doesn't "know about" it and doesn't add fuel to account for it.

You either have a rich mixture, and adding umetered air is getting it somewhere near the correct value, or you have some other problem that is dragging the motor's RPM down and letting more air in (even though the mixture is off) is helping it to run. You can check for the latter case by opening the throttle.

Any idea how the mixture is? Lean or rich? A wide-band O2 meter will tell you.

--DD
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ricardo
post Nov 21 2016, 10:42 AM
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QUOTE(Dave_Darling @ Nov 21 2016, 11:33 AM) *

You can check if air is going into the engine--just put your hand over the intake snorkel. You should feel the air getting drawn in.

Unplugging one of the hoses that is "downstream" of the air-flow meter will give you a lean mixture. Air that gets drawn in through that open hose (or the open fitting the hose had been plugged into, as in this case) is not measured by the AFM so the FI doesn't "know about" it and doesn't add fuel to account for it.

You either have a rich mixture, and adding umetered air is getting it somewhere near the correct value, or you have some other problem that is dragging the motor's RPM down and letting more air in (even though the mixture is off) is helping it to run. You can check for the latter case by opening the throttle.

Any idea how the mixture is? Lean or rich? A wide-band O2 meter will tell you.

--DD


Thanks guys i'll give your suggestions a try
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