w114 1973 280E M110 Aux Air Valve?

[body_infinity]

Hi guys started working on this 1973 280E w114 M110 engine and while most looks good the cold start idle is very low. I have to hold the accelerator for 4mins till it warms up. When it reaches normal operation temp it idles fine (a little low perhaps but doesn't stall anyway)

According to the manual I have to check the Aux Air Valve but have been unable to locate it from the diagram anyone have a picture (clear one) where this is? I think it may be jammed closed or may have been disconnected (blocked off) by previous owner?

Or is there any other thing to look at for the problem of low idle at cold start?


Thanks again guys BI

[t walgamuth]

did you check your cold start valve for proper function?


tom w

[body_infinity]

Originally Posted by t walgamuth

did you check your cold start valve for proper function?


tom w

Hi tom, yep cold start valve working (turns on and shuts off), have no problem with starting cold or hot, just the idle is very very low at startup when cold. My manual indicates the Aux Air Valve but the diagram is not clear in terms of where it is located on the m110, nor is the parts diagram very clear so was wondering if anyone could advise me via a picture or diagram and best way to take it out to test.

thanks again guyz BI

[250 Coupe]

I didn't find a listing for a W114 280E but here are two different styles of air valves.



This one is actually an idle speed control valve from a D-Jet engine.


This is the one on my K-Jet 450SEL.


Michael

[body_infinity]

The 450sel version is what I have worked with, the catalog page for the w114 with the m110 (D Jet) , that I have, shows it to be similar to the 450sel (shown before) version with the wax bulb that sits in the coolant but been unable to find it?? the other pic is new to me I don't think its for this year of car (1973 w114 M110, D-Jet). any way made some pics of the engine, any help tracing the AAV would be great, thanks again guys.

[body_infinity]

Thought the following will help clarify what I am talking about...



its number 651, looks like the outlet is from the top not side as the other pics show, anyone know how to get at it? or have a picture of it close up? It looks like it is not closing hence could be jammed which is common so wanted to try and clean it by a deep soak but need to remove it first any tips would be great.

Thanks


------------
W114 /M110 1973 280E (D-Jet)

[alabbasi]

That's one of my all time favorite cars. Especially the ones with the 5 speed manual.

[250 Coupe]

Disclaimer, I've never seen or worked on a FI M110.

My guess is that some one thought they were going to gain HP by removing the air injection setup.

The blocked off port would be the air supply to a diverter valve, part ?67. The aux air valve, #651, also draws from this connection.

The aux air valve is probably mounted in a casting on or near the water pump or maybe in the head. The hose you have circled is probably from the outlet of the valve.

You'll need to route a hose from the blocked off port to the aux air valve, which probably works fine but is blocked off.

Michael

[ctaylor738]

There's only one place on a M110 for the valve to go - on the left side of the block under all the rubber air hoses. I read somewhere that Bosch is no longer supplying them. I think that any K-Jet valve will work. You might try removing it and soaking it in carb cleaner to see if you can free it up. Also, I read that one guy had some success rapping it smartly with a hammer.

[body_infinity]

Originally Posted by ctaylor738

There's only one place on a M110 for the valve to go - on the left side of the block under all the rubber air hoses. I read somewhere that Bosch is no longer supplying them. I think that any K-Jet valve will work. You might try removing it and soaking it in carb cleaner to see if you can free it up. Also, I read that one guy had some success rapping it smartly with a hammer.

Thanks for the info had another look and yep spot on!! managed to follow the hose to the AAV which is way under the throttle body very hard to get to.... I hope I don't need to remove the throttle body to get to it? if anyone can confirm the procedure that would be great as there is no reference to it in the manual.

I have worked on other AAVs (mostly v8s) which are easy to get to but this one is hard.

Re the hammer yep thats going back some time but managed to get one working like that but also by (very very gently crushing the wax bulb) seems to get her closing ...anyway just wanted to confirm that there is no other way of getting to it??

Cheers BI

[ctaylor738]

The only time I got close to one was when I pulled the head from an engine in a 107. I managed to get the air hoses unhooked, and left the valve on the block. As I recall, that was somwhat difficult. Maybe you can get to it from underneath?

Good luck.

[romansek]

On my W107 M110 engine I had to remove the intake manifold to remove AAV. Be careful to not break the copper envelop (part inserted to the engine block) which covers the moving plunger. I cleaned my AAV in an ultrasonic cleaner bought in Harbor Freight on sale for $20 plus $5 for the Cleaning Powder. After cleaning and drying I lubricated internal moving mechanism with sewing machine oil and it works like brand new. I tested the closing function in boiling water and the AAV works. A new AAV costs $450.
Good luck.

[body_infinity]

Originally Posted by romansek

On my W107 M110 engine I have to remove the intake manifold to remove AAV. Be careful to not brake the copper envelop (part inserted to the engine block) which cover moving plunger. I cleaned my AAV in the ultrasonic cleaner bought in Harbor Freight on sale for $20 plus $5 for the Cleaning Powder. After cleaning and drying I lubricated internal moving mechanism with sawing machine oil and it work like brand new. I tested closing function in boiling water and the AAV works. A new AAV cost $450.
Good luck.

thanks roman, didn't want to hear that ...how much work is involved in removing the intake manifold? was going to try to get at it from under the car but it looks too hard.

cheers BI

[romansek]

My car has a fuel injection system which has more parts to remove. Probably you can remove the AAV without removing the intake manifold, but this will be good a time to check all the air plumbing (hoses). In my car this system is intensive. Good luck.