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Discussion Starter · #1 ·
I found some thing interesting today that I never noticed before ( if I did I must have said well it's running fine leave it alone) But it now has me very curios.
1, the advance hose off the distributor is going to the tree ( 73 with both advance and retard ports)
2, the retard hose off the distributor goes no where
3, the advance port on the carb WEBER 32/36 is going straight down to the tee
All the research I've been doing has led me to believe that this is incorrect.
From my research I am to believe the following
1, the advance hose from distributor should go to the carb advance port
2 the retard hose from the distributor should go to the tree
3 then the last nipple on the tree should go to the little port on the valve cover ( which I don't have and is wide open)and I'm not fond of the air breather turning black because of this).
So if the advance from the distributor goes to the tree and then the carb advance was attached to said tree is there technically no advance or retard?
Thank you in advance for your thoughts and help
 

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1969 Opel GT 1.9L.
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I've been dealing with some of these same issues recently on the 69. In our case the vacuum advance isn't holding vacuum. No's 1 and 2 are correct, and there are several threads out there that recommend plugging the retard port. One thing you didn't mention was the brake booster hose that should be coming off the bottom of the tree.
 

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Discussion Starter · #3 ·
AH Yes I did forget.
yes the brake booster hose goes right to the very front of the tree
In my case that hose is new as well as the brake booster and master cylinder from ogts
 

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Discussion Starter · #7 ·
I pulled it down to 10 in vac and let it sit for 10 mins and lost 3 in of vacuum in that time?
Good/bad ?
 

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Opeler
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how far of a vacuum do I put in in to test it?
I look through the fsm and don't see it and can't find it anywhere else

Never tried this?
You can do a quick test by sucking on one end of the advance hose and observing the breaker plates in the distributor (they should move slightly).

How do you test a vacuum advanced diaphragm?
Once the base timing is set to the correct position, you can connect a hand-operated vacuum pump to the diaphragm, give it a few pumps, and then watch timing mark on the flywheel advance using the timing light.
 

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I pulled it down to 10 in vac and let it sit for 10 mins and lost 3 in of vacuum in that time?
Good/bad ?
IMO that’s probably fine given that engine conditions are always changing and that there is generally a constant supply of vacuum when compared to a static test.
 

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Discussion Starter · #10 ·
Ok Thank you.
I did observe the breaker plates moving while I was tinkering before I put the hand pump on to see how well it holds and how long.
So I feel a little better there.
I looked a little closer at the tree because I thought there were 4 ports (not including the booster hose) on it and there are 3 on the tree and underneath of it was a metal tube screwed to the manifold and It appears to be pinched off.
I am assuming this would have been for an automatic trans? Just seems weird for it to be there when this is a standard.
So if I have everything connected the way it should now including the retard , Then I would have one port left over that's not used that I just plug.
 

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Discussion Starter · #11 ·

Never tried this?
You can do a quick test by sucking on one end of the advance hose and observing the breaker plates in the distributor (they should move slightly).

How do you test a vacuum advanced diaphragm?
Once the base timing is set to the correct position, you can connect a hand-operated vacuum pump to the diaphragm, give it a few pumps, and then watch timing mark on the flywheel advance using the timing light.
Yes Linsay and Thank you, I found that the other day and thought It may need to be added (if not already) to some of the tech notes and parts list Etc. that I think autoholic was compiling. Which is why I gave it a bump
 

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Discussion Starter · #12 ·
so once I get brave enough to start learning to time this little bugger I have a manometer I use for a/c stuff, if I use it to get data on vacuum while I'm playing with timing where do I hook it up at or tee it into?
 

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1969 Opel GT 1.9L.
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Hook up to full manifold vacuum port at the bottom of the carb below the throttle plates (the vacuum line goes to the retard canister). The port in the middle of the carb which hooks to the advance canister is ported vacuum and should be at or close to 0" at warm idle. Personally, I can't get it to 0" unless I drop the rpm's down to 650 and then the engine idles like a tractor so I still have some diagnosing to perform.
Your advance diaphragm seems OK; mine dropped from 15" to 10" in 10 seconds, and from 10" to 5" in 30 seconds. By comparison the retard canister held steady vacuum for about a minute; I didn't test it any longer.
 

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Discussion Starter · #14 ·
Just to update my dilemma's
I have rerouted and hooked up all my vacuum lines as they (should be)
Now the fast idle on start up no longer works?
Which is in turn leaning me towards putting it back the way it was before.
I tried on 3 different days with motor completely cold, initial start to get gas to carb then one press of pedal I hear choke plates set then it starts but no fast idle at all.
I'm thinking it's something with the retard port to the tree?
My fast idle always worked until now.
 

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Can Opeler
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Just to update my dilemma's
I have rerouted and hooked up all my vacuum lines as they (should be)
Now the fast idle on start up no longer works?
Which is in turn leaning me towards putting it back the way it was before.
I tried on 3 different days with motor completely cold, initial start to get gas to carb then one press of pedal I hear choke plates set then it starts but no fast idle at all.
I'm thinking it's something with the retard port to the tree?
My fast idle always worked until now.
Fast idle has nothing to do with vacuum.
The issue is in the choke and fast idle screw adjustment.
 

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Discussion Starter · #16 ·
Humm thanks Kyler, Maybe just coincidental it stopped working after the change?
I did accidentally touch the choke wire/lead to the choke base when I forgot to hook it back up
It sparked quickly then I tested to make sure I still had 12 volts to it incase it was long enough to blow the fuse But it was still getting voltage.
I have not messed with the fast idle screw since I first got the car and it's been fine until now?
 

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Opeler
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Fast idle has nothing to do with vacuum.
The issue is in the choke and fast idle screw adjustment.
Circle back to this posting:
 

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Discussion Starter · #18 ·
Thank you Lindsay,
I tried it again today and no go so I'll have to look into why this is happening.
Does anyone know the ohms value for the electric choke cold?
Or would that even be worth checking?
 

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Opeler
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Thank you Lindsay,
I tried it again today and no go so I'll have to look into why this is happening.
Does anyone know the ohms value for the electric choke cold?
Or would that even be worth checking?
Installled 32 36 DGEV carburetor approx. 1980.
Never checked ohms for electric choke.

Refer to attachment. Loosen three (3) adjustment screws at choke ring.
When you rotate choke housing, top sheet metal plate will open and close.
Ensure plate is verticle (straight up) when vehicle is warmed up.
Product Toy Gas Machine Nut


See the screw to the right of the choke element in this picture? It's above the brass vacuum tube. That's the fast idle speed adjustment.
Motor vehicle Gas Auto part Nut Machine
 

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Pedal Smasher
1973 Opel GT
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I would recommend plugging the retard port and connecting the advance port to manifold vacuum. Then setup your timing again. In a crude way, consider port vacuum an indicator or throttle position and manifold vacuum as an indicator of load. Port vacuum is always supposed to be zero when the throttle is closed. Manifold vacuum will be different depending on is the car at idle or did the engine just come off of full throttle. These two scenarios should have different vacuum readings. I would not want to retard the ignition with manifold advance when you let off the throttle. That would mean spark happens closer to TDC when the engine could be at high RPMs, and you want the exact opposite. I could be wrong here of course.
 
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