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Sat Mar 09, 2024 8:00 am

Hi ya’ll!

I am looking for instructions with pictures or a video on how to replace the mass airflow sensor on my 1979 Superbeetle.

I thought it would be easier but I’m stuck. Don’t have time to wait for a book in the mail - can’t get to the library - car won’t run until I fix it.

Thanks for any help.

Sat Mar 09, 2024 8:51 am

Slide off S boot, disconnect electrical plug, unbolt from air filter housing.... Installation is the reverse of removal.

What diagnostic steps led you to believe the AFM needs work? (the airflow sensor on L-jet is called an Air Flow Meter)

Sat Mar 09, 2024 10:32 am

Thanks for such a quick answer!

I need pix. I got the boot, the plug and the housing off with no problem. Where exactly are those bolts?

Long story short: I took the car to a mechanic for a minor tune-up and they screwed me (not in a good way). Overcharged me and broke the MAF. They lost the cover to its working bits. All the old VW mechanics are gone now.

Call it whatever, but when I bought another one it was called:
https://www.oreillyauto.com/shop/b/engine-sensors-...per-beetle

I’m a 70-year-old female.This is air-cooled VW #13 in my life, so I’m no stranger to working on one, but it’s been a few years, so I appreciate the help.

Sat Mar 09, 2024 10:49 am

MAF (Mass Air Flow) is a modern fuel injection term that is used incorrectly retro back onto the Bosch L-Jet fuel injection system in your Beetle. On a modern car, they really can measure and calculate the air flow, air density, and mass of the intake. Your L-Jet AFM (Air Flow Meter) does a good job measuring air flow. Then the L-Jet system approximates density (to get mass) in two different ways that I won’t bore you with.

Did your mechanic take apart your AFM? Did they open it up and make adjustments inside?

The bolts/nuts to remove the AFM are directly forward of it and under the top edge of the engine lid.

If you need a new plastic cover for the AFM, I can give you a link to buy a new one. But if an untrained mechanic made adjustments inside your AFM, you’re at some amount of risk running the engine with it as is.

Sat Mar 09, 2024 11:05 am

The black plastic part on the right in the pic is attached with 4 bolts, a couple go through that bracket that leads up to the hood hinge, and 2 more are accessed from inside the air filter housing IIRC.

BTW we generally avoid clamps on the S boot connections, in case of a backfire it's better to let it blow off, opposed to damaging the AFM internally.

Sat Mar 09, 2024 11:29 am

On my Father In Laws 77, I had to get into the MAF sensor and reset the board to new tracks. I then reset the basics. In the thread I created, I covered most of this on page 5. It might help you out!

Good luck! But do know that I have ALOT of experience with these units. They were used on multiple manufactures cars. I was always having to tweak on them to obtain decent drivability for the customer’s, customer. Use the info at your own risk. Be careful to impart no discharges, no static, no moisture. Clean, dry, dirt free or you will realize more issues down the road. Tooling has to be a decent digital DVOM. I like Fluke meters. They are the only ones I use. They have internal protective devices in them for times when the shit goes sideways. I cannot stress BEING CAREFUL & CLEAN loud enough! You the info at your own risk!

https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=80

Have fun!

Sat Mar 09, 2024 2:05 pm

Another place for a reasonably safe method to adjust your AFM is the Itinerant Air-Cooled site: https://www.itinerant-air-cooled.com/viewtopic.php?t=7761

One word of caution: the discussion goes on for 12 years and this group tries many things, like lean-burn methods at 16%-17% oxygen and above. I advise staying away from that lean-burn stuff (but I'm not an expert.)

The AFM adjustment method first described in 2010 is aimed at keeping the air/fuel ratio below 14% oxygen (approximately). That's what I do.

Sat Mar 09, 2024 3:08 pm

The sequence is important! Do not veer off of the path. Set one variable up at a time in the order on my build. The board, IF WORN, gets moved first. Followed by the remaining three fine tuning points, each one dialing further down on the peak running zone. You tune by ear. Like you would a carb. Dial them in, go for a drive. Any changes that you make need to be proven. And as with all gasoline engines, too rich is better than too lean.

Remember to adjust the valves and check the ignition system before meandering down this path. ANY issues within the mechanical side of the engine or ignition system will become huge hurdles during the tuning process. If in doubt, fix any deficiencies before tuning!

Sat Mar 09, 2024 4:15 pm

[quote="busdaddy"]The black plastic part on the right in the pic is attached with 4 bolts, a couple go through that bracket that leads up to the hood hinge, and 2 more are accessed from inside the air filter housing IIRC.

Thanks!

Perfect photo - that’s what I got. I took off the black plastic and the air filter - no problem. Just need to find those 4 bolts.

Is that rusty bolt on the top right one of the bolts that need to come off?

Sat Mar 09, 2024 4:28 pm

If you take the nut at the top of the bracket off the AFM and air cleaner should come out as a unit, then remove the air cleaner lid as well as the filter element and look for the entrance to the AFM, there's a couple 10mm bolt heads beside the rectangular hole, I can see the end of the threads of one at the lower right of the AFM in the pic.
There will also be corresponding ones on the outside of the aircleaner on the opposite (fwd) side of the AFM entrance, I can see the head of one peeking out at the base of that black bracket, it should have a buddy a little below that one.

Sat Mar 09, 2024 5:54 pm

Yay! I found all 4 bolts!

Is there some trick to getting that last one at the bottom back under the hinge? Tight space.

Sat Mar 09, 2024 5:55 pm

Take the whole unit off, aircleaner and AFM, then reassemble before putting back in place.

Sat Mar 09, 2024 6:01 pm

busdaddy wrote: Take the whole unit off, aircleaner and AFM, then reassemble before putting back in place.

Okay! Thanks so much! I’m less freaked out now. I get it!

Sun Jun 23, 2024 1:39 am

Hi all,

Just a quick question - where do i get a new 6 way connector for the AFM, its pins and a boot for it ?

Thanks for any help!

Sun Jun 23, 2024 8:23 am

yol wrote: Hi all,

Just a quick question - where do i get a new 6 way connector for the AFM, its pins and a boot for it ?

Thanks for any help!
Try Kyle: https://kyleautomotivespecialties.com/ although if your harness is that rough maybe you really just need the whole thing rebuilt?, Kyle does that.