View original topic: Rebuilt AFM installed, problem got slightly better then worse. Page: 1, 2, 3, 4  Next
jayinduluth Sun May 22, 2016 11:02 am

85 westy, with a rebuilt 2.1L automatic, but it has the original 85 AFM/air filter setup (my air fliter is square and not oval).
I've been experiencing bucking, lack of power, lack of acceleration from stop, since rebuild in June of last year. Put new O2 sensor in, new round fuel filter, and new fuel pressure regulator after it was determined the PSI was too high. Same problems exist.
Today I installed rebuilt AFM from BD and started off great. Drove down road, hesitation was gone, seemed like mid-range power was back. Headed home, I have to go up a hill. At the stop sign, I press on gas and nothing. No movement, no power, nothing, rpm don't change. I put in neutral and engine revs up fine. I back up, (I was on a slight incline at the stop sign before the hill) to a church parking lot and shut van off. I wait a few minutes, start it up, press on gas pedal and off we go. I get a mild 10mph running start at the hill and it powers up it, even accelerates a little bit. With the old AFM, it at least could go up the hill, all be it very slowly. But what the hell with the random nothingness? Grounds? plugs, etc, were done with rebuild last year.

tjet Sun May 22, 2016 1:06 pm

Mine was acting up the same way last week - AFM, no help.

I tried another ECU that I had. So far, so good.

If you don't have a spare ECU, try reseating the connector on yours & see if there's a difference

jayinduluth Sun May 22, 2016 3:57 pm

Thanks for your reply. Unplugged ECU and plugged back in after examining, looked good to me. No difference, started off ok, but then as it warmed up, back to sluggishness, missing. And apparently what I thought was flooring the gas pedal, was not true, there is one little bit that I really have to stand on to get at, that at least provides more power to it. I don't have access to a known working ECU.

jayinduluth Sun May 22, 2016 4:17 pm

Also, it appears that the ECU is from the old 1.9 as it looks like this -

and not like this which is from a 2.1 -

could that be the problem? Do I need a 2.1 ECU?

tjet Sun May 22, 2016 6:44 pm

I would say that you will need to find a 1.9 ECU, not the 2.1 Digifant. On your new AFM, is it for a 1.9 or a 2.1? - I'm not sure if there's a difference anyway.

You may also want to clean up all your grounds & reseat all the connections. Also, if you floor it, does the problem go away?

oceanair Sun May 22, 2016 6:49 pm

Keep it all the same. If you are running a 1.9 FI system then the system must be completely 1.9, not a mix and match. It will not work correctly with mixed bits.

jayinduluth Sun May 22, 2016 6:56 pm

The AFM is for a 1.9, I have a square air filter.

I wouldn't say the problem goes away if I floor it from a dead stop, but it at least moves.

tjet Sun May 22, 2016 7:20 pm

There's a procedure to check the throttle switch. Here's a VW training video for the 2.1 TB - not sure if the 1.9 is the same.

Tom Powell Sun May 22, 2016 10:34 pm

If you have a 2.1 engine, shouldn't you have a 2.1 ECU and AFM also?


jayinduluth Mon May 23, 2016 8:03 am

Previous owner did the 2.1 update, it must not have come with the other items.

vegpedlr Mon May 23, 2016 9:15 am

Sounds like you have a set up similar to mine. I have an 85 with a 2.2 WBX, built from a 2.1 case. But for all intents and purposes, it is a 1.9. It has the Dijgijet fuel system, so all the FI parts must match the 1.9. While many parts are interchangeable, there are many that aren't. In addition to fuel and engine management, the cooling system and exhaust are different. If you compare the pictures in your Bentley with your engine. Took me a while to get it sorted, but now that I know, I mostly shop with Van Cafe because Peter drives an 85 and keeps those parts in stock, while GW tends to ignore us.

Good luck dialing your running issue.

Wildthings Mon May 23, 2016 10:05 am

Lets see some pictures of the top of your engine. You will probably have the stock Digijet fuel injection for your year, but may have a hodge podge of parts from different years including Digifant parts.

You certainly might need to adjust your throttle position switch and may need to tune your new AFM. If you have vacuum leaks that could be a problem as well. It kind of sounds like the engine runs fine until the TSII sensor determines the engine is nice and hot and the fuel mixture has been fully leaned out.

jayinduluth Mon May 23, 2016 10:48 am

As of last November when fuel pressure regulator was replaced, shop found no vacuum leaks and temp II sensor was good.

I can take a better pic if needed when I get home from work.

Wildthings Mon May 23, 2016 12:49 pm

From what I can tell from your photo the FI and cooling systems appear to be correct for your model year.

jayinduluth Mon May 23, 2016 4:39 pm

I just checked the TPS and heard the clicks in the appropriate places - at the start and near the end at full throttle.

Wildthings Mon May 23, 2016 5:08 pm

jayinduluth wrote: I just checked the TPS and heard the clicks in the appropriate places - at the start and near the end at full throttle.

Put a meter on it and verify that the switches are actually passing current.

jayinduluth Tue May 24, 2016 4:33 am

I put my pos hf meter on there. It wouldn't go down to zero, but from what i've read on other threads, that's ok. When I opened up throttle it showed some mark on screen on the far left that looks like a one - maybe that's the hf symbol for infinity, who knows. I have a buddy with a presumably better multi-meter coming over after work today. But anyway, it does look like it changing when opening.

jayinduluth Tue May 24, 2016 6:13 am

Wildthings - one your posts you mention "tune your new AFM". what do you mean by that? Do you mean the CO? Because my new AFM is missing the "plug" and doesn't appear to have anything in that hole.




Wildthings Tue May 24, 2016 9:18 am

jayinduluth wrote: Wildthings - one your posts you mention "tune your new AFM". what do you mean by that? Do you mean the CO? Because my new AFM is missing the "plug" and doesn't appear to have anything in that hole.




I don't think much of certain companies that "rebuild" these units. They hook a meter up to the plug, push the flap open once or twice and if they see the readings they want they will just clean up the outside to make it look new, box it, and ship it out. The end result is you end up paying for an AFM that someone down the line tampered with and is thus way out of spec. Even if they do inspect and adjust the unit they can not tune your unit for your particular engine and thus if you engine has an induction signal that is not stock from running a non stock cam you mixture can be off.

I would suggest doing the tests on the AFM as shown in the Bentley and if you can find someone local with the knowledge have them check the settings on the AFM wiper and spring and set the idle CO. These units are similar to what was used on many different rigs of the era, so it doesn't necessarily need to be a VW specialist who checks the AFM.

Maybe buy yourself a cheap analog meter from Walmart and check your throttle position switch with it first. You really need to be 100% certain those switches are working correctly before messing with anything else. Do the testing in the Walmart lot and then return the meter when you are done, this doesn't need to cost you anything but time.

bluebus86 Tue May 24, 2016 9:40 am

from what i have heard these rebuilt units can be a roll of the ddic. I understand that there is no replacement wiperboard, so they simply test them, they cant replace them, none exist new (except old stock) you may have a very worn board on a rebuilt unit.

that is why I bought an NOS air meter box. that was a few years ago, I dont know if Van Cafe still has any or not, I grabbed an NOS one while I still could.

I know on the djet cars like the 914 that replacement boards are manufactuted, install youself. this make it like new again, but these baords are of a simpler design, only metal traces, no resistors built in as the vanagon has. the vanagon board will be more difficult to reproduce. eventually I hope some one is able to make new baords for the airmeters, else these vans will eventually die do to lack of parts.

for you problem, try putting the original air meter back in and see what happens, or exchange this rebuilt one for another, maybe it is bad. can you remove the top to examine the board without voiding warrentee?

also use a quality meter to varify the wiper operation, you should get njce steady chanbes as the air flap is moved, any jumpyness and ylu know you likely have a bad board. a quality anaolog meter works best for this measurement rather than a digital meter.

time to invest more than 20 bucks at harbour frieght and instead get a quality meter

maybe something like this.....

or this....

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