1800: efi intake plumbing

[calgary1800e]

It does, thanks Paul - I've been a carb guy to date, so this is all new to me -

Cheers,
Kerry

[c1800]

AAV can sometimes just be stuck.

Here are more details on these.

https://oldtimer.tips/en/d-jetronic/aav

I’ve managed to repair 2 valves by disassembling them. With the valve supported in a vice and tapping on the appropriate size socket with a hammer to push the innards out one end and then the other.

Picture shows it disassembled.


Once apart, a thorough cleaning and polishing of the inner sliding surfaces with 600 Wet/dry sandpaper. Reassembled with the sockets but only pushed the ends in 3/4 of the way, then off to the stove with 160 deg water and freezer nearby where I could test the action to make sure it was fully closed at 160 and fully open when in the freezer. A bit of trial and error, but seating the ends further to get full closure at cold and full open at 160 resulted in a working AAV. also had to judiciously squeeze the bulb to increase its internal pressure to get full closure.

I did this based on an online document for Jaguars, however I avoided making a sawcut and using JB weld as described in the article.

https://www.jaguarforums.com/forum/a...-procedure.doc

If the bulb no longer works they have been available on line for about $100.

Given a reman by bosch AAV is north of $500 it’s worth a try.

[Ron Kwas]

C1800;

I am following this thread with interest...I had been in contact with an (Austrian IIRC) gentleman who successfully refurbished an AAV for his Mercedes...I don't know if it was one of the ones linked, but I will study these also...I have one which I would like to disassemble and document the refurb process on...that project is on the "long-list"...unfortunately, it looks like they are "permanently" pressed together, with no provision for simple disassembly...if you can give details on a damage-free disassembly technique, I'd be very interested indeed!

Cheers

[Army]

The more modern idle control valves usually come good after a fair amount of carb cleaner / brake cleaner.

(Last generations of CIS - about K)

[c1800]

Originally Posted by Ron Kwas

C1800;

I am following this thread with interest...I had been in contact with an (Austrian IIRC) gentleman who successfully refurbished an AAV for his Mercedes...I don't know if it was one of the ones linked, but I will study these also...I have one which I would like to disassemble and document the refurb process on...that project is on the "long-list"...unfortunately, it looks like they are "permanently" pressed together, with no provision for simple disassembly...if you can give details on a damage-free disassembly technique, I'd be very interested indeed!

Cheers

Ok, here goes. I soaked the AAV in ATF/Acetone for a few days. Had no effect on the opening closing, but may have assisted with disassembly.

For the pictures I only have at the moment a disassembled one, so forgive the less than exact pictures.

In the first picture you’ll see the AAV in a vice, which is mostly there to support the AAV, rather than clamped. In fact do not tighten the vice much more than a very little bit or you’ll damage it.

Taking an appropriate size socket tap on the upper ( in the picture) sleeve to further push the sleeve in the assembly thereby pushing out the end with the bulb. Watch carefully as there is a spring and a piston in there that may fly out, which you’ll need to capture. Once the bulb end is out rotate the AAV 180 degrees (second picture) and with it supported (not squeezed) in the vice use a long socket to tap it out of the housing. Presto. You’ll have it apart.

[Ron Kwas]

C1800;

That looks quite familiar...I've had my AAV in that position a few times...but I was too shy to push it apart from the side you show, as it looked to me that any pushing from the Bulb side, would surely damage it (and so also [incorrectly] stated someone's posting I read elsewhere!)...that is why I didn't want to proceed and trash the part with a bad action...I've now studied your disassembly pic and see that the disassembly force in not applied directly to Bulb (only Bulb Assy!), I've made some markups, and I believe I finally understand what is happening...

Referencing your marked up pic, please confirm my understanding of the assembly and answer some questions:


1. Insert into Housing is a press/interference fit (Blue). What stops insertion during Assembly/Reassembly?...is there a edge or lip?...or does it simply bottom out when Bulb Assy reaches the end of the cavity, stopping insertion? During assembly, when do you know to stop pressing insert in?
2. Plunger precision-fits into Insert (Orange), and can slide within bore based on (thermal) push by Actuator of Bulb Assy, or counter-push by Return Spring.
3. Is Violet OD of Bulb Assy slightly undersized for precision, but not interference-fit into Housing?
4. Disassembly force is applied at Green, (applying any force on Sensing Bulb is a big NO-NO!) which presses out Insert indirectly (dotted Green).
5. Assembly/Reassembly force is at double Green.

Please confirm: Plunger and Insert are both of Alu (which would explain why Plunger freezes in place). While pressing Insert and Bulb into Housing during Assembly/Reassembly, Insert OD indeed presses on Bulb Assy OD , but only to hold it in place...at the same time, Actuator of Bulb Assy presses on Plunger determining its final (thermally dependent) position within Insert...do I have this right? If so...I like it...its an inspired, simple, producible design...its only long-term weakness it the darned Alu with when it corrodeds and grows, locks up the function!!

Point of information: The shape of the air bypass opening in the Insert wall is unique to the engine application (I saw a Mercedes Insert in my travels, and the orifice shape was quite different)...this obviously determines the amount of bypass air as a function of Actuator excursion, so I expect shape is a function of engine displacement and how much extra air they want to add to raise the idle...

Cheers

[Army]

If I remember correctly there´s a voltage spec for when it is operating correctly (Later KE ICVs are harder to measure as you need to measure current)

[mocambique-amazone]

Hi Army, this type of AAV is without any voltage or current. It is 100% mechanicly. The k-jet has a electric driven AAV, the D-jet a mechanic one. A after market solution is to use the k-jet one at a d-jet engine. I prefer to overhoul the mechanic one, like C1800 is doing.
Regards, Kay

[Ron Kwas]

C1800;

In studying the situation (especially your pic 2) a bit more, I think I've answered my Q1...there is no lip for Bulb Assy to bottom out on when it is pressed in...the bore is straight through (please confirm this), so what stops Bulb Assy is that it is pressed until flush only with Housing base...and no more!...so when reassembling, Housing must be on a flat surface with a hole to just clear sensing Bulb, and when Bulb Assy hits this surface, pressing force must stop...! THIS factor is key in allowing Bulb and Insert internals to be pushed out the other way for disassembly...!

In any case, your info is the secret to disassembling this component without trashing it, and just what I needed! Yippee, and thanks!

Cheers

[c1800]

Hi Ron, yes, there is no lip.

Upon reassembly you’ll then need to test the opening and closing , hence the 160 deg water and freezer. Initially I didn’t tap the insert all the way in to leave some adjustment if needed. I ended up with the insert flush with the housing, and required more adjustment to get the orfice fully closed at 160. So I resorted to some slight squeezing of the bulb. There are two adjustment nuts available on the actuator, but of course they are not accessible when reassembled, and how would you know where to adjust them when disassembled?

Let us know how you make out when you give this a try.

Now to figure out how to fix the MPS!