1800: - efi intake plumbing

calgary1800e · Mar 5th, 2018, 15:49

Perhaps dumb questions, but on my 1971 1800e, I am trying to sort the plumbing around the intake (I didn't take it apart).

Below the cold start throttle valve switch, there are two 1/2" open ports, one in front of the butterfly, one behind. I see pictures of cars with the oil breather hose running from a top port and I think out the front of the two lower ports toward the air intake. I also see there are cars that run this direct - any reason for this?

(I am not referring to the two side ports for the exhaust recirculating system).

On those that run the oil breather line direct, the top port is usually blocked. If I run direct, should either or both of the lower ports be blocked? Or are they moisture drains or something...?

Also - for the line running from the intake to the booster, I sometimes see a black union, looks like a plastic valve - something to adjust vacuum to the booster or something? required?

Thanks!
Kerry

Army · Mar 5th, 2018, 16:12

I assume in the brake booster line there is a non return valve so the booster remains with the ¨power¨ for as long as possible.

Bosch / Mercedes CIS usually incorporates an air idle control valve which takes crankcase air and adds it to the mixture chamber behind the main throttle control plate (which is fixed to stay shut at idle but the engine still needs air)

I´m not sure how Volvo did this but I guess it can´t be too too different.

If someone can´t give you the answer you want post up some pictures of what you´ve got and I´m sure that´ll help.

c1800 · Mar 5th, 2018, 18:16

Based on your description The 2 ports you refer to are for connection to the auxillary air valve that is attached to the head below the thermostat. It’s function is to increase idle when the vehicle is cold by allowing some extra air into the intake.

The plastic valve in the brake booster line is a one way valve.

There isn’t an EGR system on these cars.

There’s a Fuel Injection Fault Tracing Manual as well as an 1800E service manual available for download on this site.

http://volvo1800pictures.com/sweden/...on_misc_en.php

If you can post some pictures that would help.

calgary1800e · Mar 5th, 2018, 20:10

Quote:

Originally Posted by c1800

Based on your description The 2 ports you refer to are for connection to the auxillary air valve that is attached to the head below the thermostat. It’s function is to increase idle when the vehicle is cold by allowing some extra air into the intake.

The plastic valve in the brake booster line is a one way valve.

There isn’t an EGR system on these cars.

There’s a Fuel Injection Fault Tracing Manual as well as an 1800E service manual available for download on this site.

http://volvo1800pictures.com/sweden/...on_misc_en.php

If you can post some pictures that would help.

Thanks re the Brake booster -

Regarding the intake - here is a picture of the two ports. Dead centre (you can see the other two hoses off to the right). My car seemed to have a hose from the air filter assembly with a sleeve that looks like it should fit, but doesn't slide in easily...

c1800 · Mar 5th, 2018, 21:52

The line in question comes from the charcoal canister up front where the air filter is. Do you have a charcoal canister? They were often removed when they rusted out.

Ok, looked again, those 2 ports underneath and behind the charcoal canister line are blanked off. I don’t know why they are there. They appear to be internally connected to the AAV ports.

In any event my 71 1800E has the same arrangement, plugged from the factory and not used for anything.

Are yours open or plugged?

calgary1800e · Mar 5th, 2018, 22:47

I will have to confirm that the rear one is a through opening - I could feel the opening behind the throttle, and on the bottom, but I didn't check to see if it was sealed in between. The one in front is open for sure.

I can see why, if the oil breather is plumbed to the air intake that the top and bottom front port would be opened, but I could not see a reason for the rear port behind the butterfly, seems counterintuitive to have a butterfly with an intentional leak behind it...

Actually, I can't really see why the oil breather needs to be plumbed at all - often they just have a filter on them to keep gunk from getting in.

Anyway, this is probably one of the least of my problems at the moment.

Thanks!

Mar 5th, 2018, 15:49	#1
calgary1800e New Member Last Online: Dec 30th, 2018 19:11 Join Date: Feb 2018 Location: Calgary	efi intake plumbing Perhaps dumb questions, but on my 1971 1800e, I am trying to sort the plumbing around the intake (I didn't take it apart). Below the cold start throttle valve switch, there are two 1/2" open ports, one in front of the butterfly, one behind. I see pictures of cars with the oil breather hose running from a top port and I think out the front of the two lower ports toward the air intake. I also see there are cars that run this direct - any reason for this? (I am not referring to the two side ports for the exhaust recirculating system). On those that run the oil breather line direct, the top port is usually blocked. If I run direct, should either or both of the lower ports be blocked? Or are they moisture drains or something...? Also - for the line running from the intake to the booster, I sometimes see a black union, looks like a plastic valve - something to adjust vacuum to the booster or something? required? Thanks! Kerry

Mar 5th, 2018, 16:12	#2
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	I assume in the brake booster line there is a non return valve so the booster remains with the ¨power¨ for as long as possible. Bosch / Mercedes CIS usually incorporates an air idle control valve which takes crankcase air and adds it to the mixture chamber behind the main throttle control plate (which is fixed to stay shut at idle but the engine still needs air) I´m not sure how Volvo did this but I guess it can´t be too too different. If someone can´t give you the answer you want post up some pictures of what you´ve got and I´m sure that´ll help. __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Mar 5th, 2018, 18:16	#3
c1800 Master Member Last Online: Today 05:36 Join Date: Oct 2013 Location: Alberta	Based on your description The 2 ports you refer to are for connection to the auxillary air valve that is attached to the head below the thermostat. It’s function is to increase idle when the vehicle is cold by allowing some extra air into the intake. The plastic valve in the brake booster line is a one way valve. There isn’t an EGR system on these cars. There’s a Fuel Injection Fault Tracing Manual as well as an 1800E service manual available for download on this site. http://volvo1800pictures.com/sweden/...on_misc_en.php If you can post some pictures that would help. Last edited by c1800; Mar 5th, 2018 at 18:29.

Mar 5th, 2018, 21:52	#5
c1800 Master Member Last Online: Today 05:36 Join Date: Oct 2013 Location: Alberta	The line in question comes from the charcoal canister up front where the air filter is. Do you have a charcoal canister? They were often removed when they rusted out. Ok, looked again, those 2 ports underneath and behind the charcoal canister line are blanked off. I don’t know why they are there. They appear to be internally connected to the AAV ports. In any event my 71 1800E has the same arrangement, plugged from the factory and not used for anything. Are yours open or plugged? Last edited by c1800; Mar 5th, 2018 at 21:59.

Mar 5th, 2018, 22:47	#6
calgary1800e New Member Last Online: Dec 30th, 2018 19:11 Join Date: Feb 2018 Location: Calgary	I will have to confirm that the rear one is a through opening - I could feel the opening behind the throttle, and on the bottom, but I didn't check to see if it was sealed in between. The one in front is open for sure. I can see why, if the oil breather is plumbed to the air intake that the top and bottom front port would be opened, but I could not see a reason for the rear port behind the butterfly, seems counterintuitive to have a butterfly with an intentional leak behind it... Actually, I can't really see why the oil breather needs to be plumbed at all - often they just have a filter on them to keep gunk from getting in. Anyway, this is probably one of the least of my problems at the moment. Thanks!

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