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914World.com _ 914World Garage _ 1975 1.8 L L-Jet

Posted by: jim_hoyland Mar 6 2006, 10:00 PM

Over the weekend, I read several threads on the L-jet hose connections; then went and looked at mine. Map a map so I could verify the connections. I have a couple of basis questions now:

1. The throttle body has two small hoses; one goes to each side of the distributer-retard and advance vacs.
Question: Does it matter which goes to the advance and retard ?

2. AAR valve was tested and it closes when 12 volts is applied.
Question: How far should it open ? Looked about 25% open to me; and a second one does the same.

3. The decel valve has 2 large hose connections and one small one. the small one hooks up in a Y to the Fuel pressure regulato, ant hen hookk to a second Y to the ERG and then to the plenum.
Question: Is this correct ?

4. Are the boots , between the AFM and throttle body replaceable with any after market products?

Posted by: jim_hoyland Mar 6 2006, 10:18 PM

Picture or AAR in open position...

Attached image(s)

Posted by: bd1308 Mar 7 2006, 12:27 AM

QUOTE (jim_hoyland @ Mar 6 2006, 10:00 PM)
Over the weekend, I read several threads on the L-jet hose connections; then went and looked at mine. Map a map so I could verify the connections. I have a couple of basis questions now:

1. The throttle body has two small hoses; one goes to each side of the distributer-retard and advance vacs.
Question: Does it matter which goes to the advance and retard ?

2. AAR valve was tested and it closes when 12 volts is applied.
Question: How far should it open ? Looked about 25% open to me; and a second one does the same.

3. The decel valve has 2 large hose connections and one small one. the small one hooks up in a Y to the Fuel pressure regulato, ant hen hookk to a second Y to the ERG and then to the plenum.
Question: Is this correct ?

4. Are the boots , between the AFM and throttle body replaceable with any after market products?

1.yes. The PelicanParts hose Diagram for the L-jet helps wonderfully.

2.25% open when cold is good. Plug *TOP* should be perpendicular to AAR, not off by any degree to make the sensor work. Mine was liek this, and it stayed open when warm and caused problems. There is also an air leak between the body of the unit and the plug portion...a epoxy application sealed things up and made sure the plug part didnt move. I have a AAR in pieces, i'll post pics tomorrow.

3. *cough* see 1 *cough*

4. Not that I know of, but mine are good so I didnt need to look. Actually I have one that will work, lemme know if you dont find an answer....

b

Posted by: alpha434 Mar 7 2006, 01:36 AM

Hmmm. That's funny. My throttle body doesn't have the distributor retard plug. That's because there were a few different revisions to the L-jet. When you go to look up the diagrams, make sure that your engine number matches the chart number.

Posted by: bd1308 Mar 7 2006, 06:08 AM

QUOTE (alpha434 @ Mar 7 2006, 01:36 AM)
Hmmm. That's funny. My throttle body doesn't have the distributor retard plug. That's because there were a few different revisions to the L-jet. When you go to look up the diagrams, make sure that your engine number matches the chart number.

alright look, I had enough of this.

there are THREE VERSIONS OF L-JET FOR THE 914.

the 1974 version, and the 1975 version...The AFM's are different ( 1975 has a air intake temperature sensor built into the AFM)

there are companies who purchased licenses from BOSCH to use L-Jet on thier cars.

The third type of L-jet had a optional plug-in module called the Altitude Compensator. This would change the mixture for very high-altitude running ( i think lean, but i JUST woke up). That's the three systems.

b

Posted by: Cap'n Krusty Mar 7 2006, 09:34 AM

QUOTE (alpha434 @ Mar 6 2006, 11:36 PM)
Hmmm. That's funny. My throttle body doesn't have the distributor retard plug. That's because there were a few different revisions to the L-jet. When you go to look up the diagrams, make sure that your engine number matches the chart number.

914 L-jet ALWAYS has a retard connection. Setting the timing correctly requires it. The larger nipple on the TB is the retard fitting, the smaller the advance fitting. You need them both. SOME later 2.0 VW Busses used single vacuum, but that distributor is inappropriate for use on a 1.8 914. The Cap'n

Posted by: Dave_Darling Mar 7 2006, 08:53 PM

Many of the 74+ cars did not have a vacuum advance fitting on the throttle body. The distributor dashpot (the vacuum cannister thingie) was unchanged, and still had two fittings on it. When there is only one fitting on the TB, you plug the advance fitting on the distributor dashpot to... Nothing. Just run a piece of hose under the manifold somewhere so the Smog Monkeys (or others who look in your engine bay) don't freak out.

The advance fitting was added back for the EGR motors at the very least, and possibly some others.

--DD

Posted by: Rand Mar 7 2006, 09:12 PM

Posted by: Cap'n Krusty Mar 7 2006, 09:27 PM

QUOTE (Dave_Darling @ Mar 7 2006, 06:53 PM)
Many of the 74+ cars did not have a vacuum advance fitting on the throttle body. The distributor dashpot (the vacuum cannister thingie) was unchanged, and still had two fittings on it. When there is only one fitting on the TB, you plug the advance fitting on the distributor dashpot to... Nothing. Just run a piece of hose under the manifold somewhere so the Smog Monkeys (or others who look in your engine bay) don't freak out.

The advance fitting was added back for the EGR motors at the very least, and possibly some others.

--DD

True of the 2 litre cars, but I don't recall seeing a 1.8 w/o the advance, and I worked at a dealer for nearly the entire MY. I was one of 2 914 guys there, so I PDI'd at least half the ones we sold. The Cap'n

Posted by: jim_hoyland Mar 7 2006, 09:54 PM

Thanks for the replys: The Throttle body's hose connections appear to be the same size...

Attached image(s)

Posted by: jim_hoyland Mar 7 2006, 09:57 PM

Last question for this thread; The decels large hoses attach to the top portion of the S shaped boot and to the manifold. Does it matter which goes where ?

Attached image(s)

Posted by: alpha434 Mar 7 2006, 10:42 PM

QUOTE (Dave_Darling @ Mar 7 2006, 06:53 PM)
Many of the 74+ cars did not have a vacuum advance fitting on the throttle body. The distributor dashpot (the vacuum cannister thingie) was unchanged, and still had two fittings on it. When there is only one fitting on the TB, you plug the advance fitting on the distributor dashpot to... Nothing. Just run a piece of hose under the manifold somewhere so the Smog Monkeys (or others who look in your engine bay) don't freak out.

The advance fitting was added back for the EGR motors at the very least, and possibly some others.

--DD

It doesn't matter, Dave. Ialready said that and so it's autoomatically wrong.

Posted by: Cap'n Krusty Mar 7 2006, 11:28 PM

QUOTE (jim_hoyland @ Mar 7 2006, 07:57 PM)
Last question for this thread; The decels large hoses attach to the top portion of the S shaped boot and to the manifold. Does it matter which goes where ?

Does the fact they're 2 different sizes of "large" mean anything to you? The Cap'n

Posted by: Cap'n Krusty Mar 7 2006, 11:30 PM

QUOTE (jim_hoyland @ Mar 7 2006, 07:54 PM)
Thanks for the replys: The Throttle body's hose connections appear to be the same size...

The one we see is the same size as the one we see. What about the one we don't see? The Cap'n

Posted by: bd1308 Mar 8 2006, 07:58 AM

I have a 74 L-jet system and it has both the retard and the advance connections.

b

Posted by: thewheel69 Mar 20 2006, 10:02 PM

Hey, while we are on the topic... does anyone know where I can get my hands on the elbow boot between the airbox and throttle body? Dont know the technical term (intake boot?)

Any remedies or solutions if not?

How about a K&N cold air intake aftermarket system?

Thanks for the help!