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Wed May 31, 2017 9:56 am

I just felt I had to post my findings with a hard start, had to keep pumping gas pedal and would not idle until the engine was @ operating temperature. Even then I was unable to set timing or drive the vehicle with out the engine shutting off.

If you discover a problem like this one with your 83-85 Vanagon 1.9 water cooled engine. First thing you want to do is check this valve. My valve was in the closed position and it just cost me a lot of money and frustration. It took me over 3 weeks to nail down this faulty valve. Anyone who knows anything about this engine will tell you that this part can and I repeat cause you a lot of sleepless nights. I will also tell you that removing and blocking it off, will not solve the problem. Also a costly part to replace, but a must part for proper engine operation. Check my photo gallery for a picture of this part. Final Note: Absolutely must be grounded to the engine block.

Nova73
85 Weekender 1.9
Akron,PA

Sun Apr 15, 2018 7:04 pm

Felt I should follow-up on this post as it (and the digijet manual) helped fixed a similar problem I was having with my 1985 1.9l Westy. I was having cold start issues just as the prior member mentioned. It would start, run for somewhere between 2-20 seconds then sputter out and die. Reving the engine using the gas pedal (which actually does not provide fuel, but allows more air to enter the engine) was the only way to keep it running. Then after a few minutes (when it finally warmed up) it would idle just fine.

When I removed the air auxiliary regulator, it was completely stuck closed. When the van is cold/sitting for a while the valve should be open to allow more air to enter and assist the idle during start-up. As heat is produced by the attached 12 volt connector and the engine, the valve begins to close. In my situation the valve was stuck closed on start-up forcing me to add air by reving the pedal to keep the idle at a sustainable level until it warmed up enough to not need the air aux regulator.

I used carb cleaner to remove the dirt and grime build up from over the years. After I cleaned, I did the freezer test and the valve stayed open. Reinstalled and the van idled smoothly.

If you have a 1983.5-1985 1.9l and you are having similar start then die symptoms when the engine is cold... check the auxiliary air regulator, it might need to be cleaned or repaired.

Mon Apr 16, 2018 10:28 am

When engine is cold, if the hose connecting the aux air valve to the intake boot were disconnected, would that help the diagnostic process? ("extra" air allowed into intake makes engine run better, engine cold?)

Even though the valve is adjustable, in terms of the valve itself, I'd guess at least 90% of the time the valve disc has simply gotten stuck or has limited travel. i.e. the PO hasn't misadjusted the valve.

The later style throttle switch plug on the late 1985 Vanagon 1.9 is the same as the aux. valve plug. If those 2 plugs are mixed up, the engine may start but will run poorly at any engine temp.

Neil.

Sun Jun 03, 2018 4:57 pm

Good question, Neil. I'm not entirely sure how this would affect the vacuum system overall? The AAR receives air intake from the S-Boot which is connected to the Air Flow Meter. So, if you disconnected the AAR, it would create a pretty big leak in the overall vacuum system and possibly make it hard to isolate the problem. Then again, you would be allowing the engine to receive more air, so it may work if the AAR is stuck closed when the engine is cold!

My guess is if you tested the AAR by taking the hose off (side with electrical plug) and it was closed when cold, I bet you'd likely see an increase in idle. I'm just not sure you could be 100% it is the AAR without further testing. It's not a difficult process to take the AAR out, just be sure not to strip the bolts because they are tapped into the engine block.

Tue Aug 11, 2020 4:25 pm

hey this info is helpful. Im not savvy in the automotive repair world. I'm having issues with my idle as well. as soon as I take my foot of the throttle the van stalls. I had my father in-law look at it as well as a mechanic (Hyundai) while at the cottage. we found out that the auxiliary air regulator my be the problem. we adjusted the idle and removed the hose to the elbow and pinched the vacuum hose and it still works but as time went on to move the van it just simply did it again and stalled out. the engine runs smoothly when running. obviously I don't want to keep that bandaid on. how do I fix the regulator? also if not where would I get a reliable part? its next to impossible to find and also in canada.
id like to save on the currency exchange. thanks for the help in advance! cheers!

Tue Aug 11, 2020 5:34 pm

W_ruk wrote: hey this info is helpful. Im not savvy in the automotive repair world. I'm having issues with my idle as well. as soon as I take my foot of the throttle the van stalls. I had my father in-law look at it as well as a mechanic (Hyundai) while at the cottage. we found out that the auxiliary air regulator my be the problem. we adjusted the idle and removed the hose to the elbow and pinched the vacuum hose and it still works but as time went on to move the van it just simply did it again and stalled out. the engine runs smoothly when running. obviously I don't want to keep that bandaid on. how do I fix the regulator? also if not where would I get a reliable part? its next to impossible to find and also in canada.
id like to save on the currency exchange. thanks for the help in advance! cheers!
What year Westy?
And please understand that the Aux Air Valve is there for Cold Idle RPM increase to help prevent stalling at idle until the engine warms up.
Basically , like a fast idle circuit on a Carburetor as in years ago, but just allows air.

Once the 12 volt heater circuit at the valve warms up the bimetal element, the disc starts to close off air flow.
If you unscrew the 2 bolts holding the valve to the engine, you can remove it, clean it, and test it by putting it in your freezer.
With a good chill, it should move to its open position.
You also have to make sure none of the hoses to the valve are cracked. Especially the stock 90 degree one if you still have it.

Wed Aug 12, 2020 8:45 am

thanks for the tip. whats the best way to clean it? any tips? ill inspect the hoses and elbow etc. but I have a hard time understanding, I guess there seems to be another issue then. I can start the my vanagon (1982) and I keep the throttle going and obviously like I said before if I take my foot off it stalls. I've driven it with this issue for a few hours. the engine should be warm one would think and again as soon as I take my foot off it still stalls. any ideas what the issue could potentially be? I have to drive it tmw and it will work and run but once I get it to the next location it will be parked and ill have my step dad to help me. he isn't really familiar with fuel injection. but has had a VW Thing for a few years so and has had a body shop years ago.. so he knows cars. just trying to get as much info possible so I can get to the bottom of this. thanks again!

Wed Aug 12, 2020 11:07 am

W_ruk wrote: thanks for the tip. whats the best way to clean it? any tips? ill inspect the hoses and elbow etc. but I have a hard time understanding, I guess there seems to be another issue then. I can start the my vanagon (1982) and I keep the throttle going and obviously like I said before if I take my foot off it stalls. I've driven it with this issue for a few hours. the engine should be warm one would think and again as soon as I take my foot off it still stalls. any ideas what the issue could potentially be? I have to drive it tmw and it will work and run but once I get it to the next location it will be parked and ill have my step dad to help me. he isn't really familiar with fuel injection. but has had a VW Thing for a few years so and has had a body shop years ago.. so he knows cars. just trying to get as much info possible so I can get to the bottom of this. thanks again!
You can use Carb Cleaner or Brake Cleaner. Both can also be used to try lightly spraying around the intake manifold while the engine is running after you clean the valve up, since it sounds like you may have a vacuum leak with the engine running.
That Aux Air Valve just gives you a higher cold engine idle speed, then closes off. Even if it’s stuck closed,you have another issue going on with the dying out on a warm or hot engine.
Timing has to be right, no vacuum leaks from cracked hoses, loose connections, or leaking seals/ gaskets, and your throttle switch needs to read correctly with the throttle closed too.
All of this is covered in posts here on Samba, do you have any manuals like a Haynes or Bentley to follow along and learn if someone gives you info?

Good news is that you need more patience than special tools working on the Vanagon, so ANY automotive repair experience your relatives can offer is useful as you build knowledge with yours.
You may just have to tweak that info a bit as it applies to a VW air cooled engine.

Wed Aug 12, 2020 11:33 am

It really doesn't sound like the AAR is your main problem. With the valve removed and cold you should be able to see all the way through the valve. If you let the valve sit in a 200°F oven and then look down through it, you should not see light.

I agree with others it sounds more like you have a vacuum leak or even multiple vacuum leaks. Changing all the vacuum lines, boots, and elbow is a good idea if they are very old. A lot of time the rot out first on the bottom so visual checks of the various hoses and other pieces often comes up short.

Wed Nov 25, 2020 8:21 pm

I have been searching around here in the samba forums along with using my Bentley manual to iron out some issues with our newly purchase '84 Westy project. It still has it's 1.9 gas engine. I have it running fairly well now, but only driven for a couple miles at a time until I feel more comfortable about venturing out. I did mention this was a 'project'.
Since this thread is titled "Auxiliary Air Regulator Valve" I thought I'd post a couple questions.
When the engine is warmed up and the AAR is closed, is it supposed to block all and any air flow through it???
Initially my AAR seemed to be stuck almost closed and I cleaned it with carb cleaner/pb blaster and feel that it is working like it should.
I've tested it, it's open (can see through the plate that moves) when engine is cold and it closes up when warm (hole in plate moves past the other side). However, air can still flow through my closed AAR. So right now when warm I still have a slight searching/hunting idle and crimping the the hose from the s-boot to the AAR does eliminate the search/hunt and the idle slows and is steady .
Will further cleaning/soaking of the AAR help the valve close up more than it does now? Is there some rubber membrane inside AAR that eventually breaks down that makes it to where the valve will no longer close off?

Thanks.

Thu Nov 26, 2020 7:42 am

69aircooled wrote: I have been searching around here in the samba forums along with using my Bentley manual to iron out some issues with our newly purchase '84 Westy project. It still has it's 1.9 gas engine. I have it running fairly well now, but only driven for a couple miles at a time until I feel more comfortable about venturing out. I did mention this was a 'project'.
Since this thread is titled "Auxiliary Air Regulator Valve" I thought I'd post a couple questions.
When the engine is warmed up and the AAR is closed, is it supposed to block all and any air flow through it???
Initially my AAR seemed to be stuck almost closed and I cleaned it with carb cleaner/pb blaster and feel that it is working like it should.
I've tested it, it's open (can see through the plate that moves) when engine is cold and it closes up when warm (hole in plate moves past the other side). However, air can still flow through my closed AAR. So right now when warm I still have a slight searching/hunting idle and crimping the the hose from the s-boot to the AAR does eliminate the search/hunt and the idle slows and is steady .
Will further cleaning/soaking of the AAR help the valve close up more than it does now? Is there some rubber membrane inside AAR that eventually breaks down that makes it to where the valve will no longer close off?

Thanks. . I’ve never broken one down to see the internals, but I thought it was more of an all metal affair inside.
With the hose pinched off, what is the idle speed of your engine?

Thu Nov 26, 2020 7:54 am

It’s been a long time, but I don’t believe you get an absolute seal when it’s to temp. It’s more of a volume bypass.

Thu Nov 26, 2020 9:09 am

jlrftype7 and MarkWard, thanks for the replies.
I was hoping to hear that this unit was basically metal and that being more of reducing the air volume. So my assumption is that it is working properly and that I need to further test/evaluate things. This vehicle being a recent purchase and not knowing full history I'm just going to have to get to know this 36 year old a little better. :lol: Right now it's a little bit of a love/hate thing.
Pinching off the hose results in an idle at or just below 800rpms.

Thu Nov 26, 2020 9:31 am

There is no substitute for a systematic troubleshooting methodology when you have a no start or poor running vehicle.

“Check this first “ from a small sample size is not a Methodology.

It’s good info on how to evaluate the AAR if you get led there.

Thu Nov 26, 2020 9:31 am

The fuel cutoff on the Digijet happens at a very low rpm so if your engine wants to idle faster than that it will surge continually at idle. There are several places where extra air can get into the intake air stream.

-Vacuum leaks from any source are a big one, lots of boots and old hoses to crack and let air in. Old hoses, boots, and elbows can look fine on top and be rotten on the bottom. I like to remove each and every rubber piece of the intake system and inspect it end to end and then even if it looks good, seal one end and suck on the other to see if it holds vacuum.

-The throttle valve bushings wear out with the miles and the butterfly can wear into the sides of the throttle body. Remove the throttle body and hold it up to a light, you will very likely find damage here.

-I don't know how tightly an AAR should seal, but it sounds like yours may not be sealing well enough. Maybe soak it longer and adjust it so it doesn't open quite as much?

- The intake manifolds may not be sealed well to the heads it is common to find a leak there. Check the torque on the bolts and replace the gaskets if need be.

Sat Nov 28, 2020 7:39 am

Thanks all the replies. I'm not one to throw money at new parts unless I can fully know that it is needed. I'm glad to have samba folks that have more experience on these Vanagons and willing to share.
I had assumed that I was chasing some vacuum leak somewhere, just didn't know where. Prior to my posting I had checked the throttle shaft for radial wear and it is tight radially. However, it has more than a mm of axial play! I haven't had a chance to pull the TB out, but assume that mm stems from wear on the inside. I have checked and feel the hoses are good and the S-boot is new. I'll get the TB out and report back.

Tue Apr 15, 2025 5:26 pm

I know it’s been a little while for this thread but does anyone know how much the valve should be open? It depends on the temperature I assume? In checking this valve I threw it in the freezer for 30 min and the valve was open but I would say no more than 80% open rather than 100%. Im chasing down a cold start issue similar to the earlier posts here and have checked many other systems with no avail. I was wondering if mine is functioning but no all the way. I still have to hold the pedal on cold starts for a good two minutes before I can drive.

Curious why does it need to be grounded to the engine block? It seems mine was functioning the same either way.

Tue Apr 15, 2025 5:47 pm

It should have been all the way open after 30 minutes in the freezer. The wire is for the electrical component of the valve and is the primary means of warming the spring up to close the opening. On really cold mornings, without the electric connection, the engine can be warm enough to not need the aux valve but the ambient air temps will be too cold to let it close. You end up with a high/surging idle until it finally warms up. Clean it out well with carb cleaner and see if it opens more when cold. It's been a while, I think there is some adjustment you can make, as well, to get it to open all the way.

Hans

Tue Apr 15, 2025 9:11 pm

The valves are somewhat generic and many can have the same bore size, but have different shutters or whatever they are call. IIRC the AAR for a Type 4 engine does not open to the full size of the bore but close, so 80% is likely normal.

The electrical schematics shows the AAR for the air cooled is grounded through the ECU by a white wire, while the AAR for the 1.9L goes to a ground (likely on the engine block) via a yellow wire. It doesn't look like either one is grounded though its body and mounting point.

Wed Apr 16, 2025 5:48 pm

Hmm I bit the bullet and bought a reconditioned one after I tried to use the adjustment screw and broke it clean off.

Not sure I trust reconditioned knowing that to get in these things you have to cut them open basically but hopefully the ones at bus depot work well. I’m still not 100% sure that’s my problem but I’m running out of roads to go down.

These things really test your patience! It’s my first Vanagon and have been studying the Bentley for 6months straight now. Taking it on its first road trip this weekend. Wish me luck.