Rebuilt AFM installed, problem got slightly better then worse.

[jayinduluth]

I was thinking I should just open up my old one and adjust it and throw back in there and send the one I bought back to BD. I would't open the new one up.

I'm hesitant to get in too deep with the throttle adjustment because I'm planning on camping this weekend in it and its drive-able now (well unless I encounter any sort of incline from a complete stop...), just not optimal.
_________________
85 Westy with 91 2.1L

[tjet]

Fyi, mine is acting up again. I previously tried another AFM & an ECU - no help.

It seems to start bucking after it's warmed up. I'm going to unplug the o2 sensor & give it a try...

[Howesight]

Hi Jay:

I don't think your AFM is the problem, but it is possible. I am chiming in because you live in Duluth, which is second only to Toronto, Ontario in the amount of salt they apply to the roads. My Syncro has barely had any salt exposure, but even it has had corrosion issues on parts of the wiring. My bet is that you have corrosion-affected wiring in more than one part of your fuel injection system.

It does not matter that your engine is actually 2.1 litre displacement. You fuel injection system will be 100% referable to the Digijet Pro-Training Manual and the Bentley manual for trouble-shooting, testing, and repair.

The adjustment of the CO via the screw on the AFM will not cause the symptoms that you describe. That screw mainly affects the idle CO readings and the CO readings at very low throttle settings. If your oxygen sensor, wiring and Lambda system in the ECU are operating properly, then the Lambda system will correct any mis-adjustment of the CO screw once the engine is warmed up.

One poster above suggested that you try a known-good ECU. I think that is good advice. However, before buying a new or "rebuilt" (in fact, re-soldered) ECU, it is useful to perform all of the electrical tests in the Digijet pro-training manual. You can find it here:

http://www.vanagonauts.com/files/Digijet_FI.pdf

There are a number of ground wires in the engine bay that influence the EFI system, some directly, some indirectly. Wherever a ground tests less than perfect, carefully clean the ground connection area and re-check. If still less than perfect, strip back some of the insulation on the ground wire near the terminal end to check for corrosion of the copper conductor. It should be shiny copper coloured and if it is, instead, brown, then you need to address it. I have recently had great success using CLR on mildly-corroded switches, (submersing and soaking for an hour or more) so that may be an option, but the speediest way is to cut back the corroded part and crimp a new terminal in place, using a proper terminal and a proper crimper. Here's one source:

https://www.germansupply.com/home/customer/product.php?productid=17094

You should also check all the usual sources of vacuum leaks and eliminate/correct them. The common places are:

1. Rubber boot connecting AFM to Throttle body: It cracks at the bellows and/or is loosely attached;
2. Brake Booster hose: loose or leaking;
3. Hose pieces connecting the intake plenum to the intake runners: They rot from oil inside the manifold;
4. Injector O-rings dried out;
5. Intake flange-to-head gasket;
6. hose from breather tower to intake plenum: loose or rotten;
6. Breather tower diaphragm broken: Test by removing oil filler cap when engine is idling. If idle speed is affected, the diaphragm is toast.
7. Fuel evaporative hose/system. Plug off at the manifold to test. If no change in idle speed, evaporative system is not causing a vacuum leak (but may still be defective).
8. Hoses between idle-up solenoid(s) and intake plenum: loose, eroded or disconnected.
_________________
'86 Syncro Westy SVX

[tjet]

Good info howesight. I just unplugged my o2 sensor & I'm heading out now. Lets see how that works.

[jayinduluth]

good grief, I completely forgot that I did this on Sunday and my rpm did not change when I pinched the hose. However, if I'm recalling correctly (which we all know how well that is working..) the rpm didn't change after it warmed up either, but I'll test again when I get home.

Thanks Howesight!
_________________
85 Westy with 91 2.1L

[jayinduluth]

I assume the pinching of the hose an auxiliary air regulator is only for the 1.9? I'm home now and I'm not seeing that regulator, that hose goes to a T underneath the the air filter, so it must be part of the 2.1.

_________________
85 Westy with 91 2.1L

[Wildthings]

[hdenter]

There should be two hoses coming off the "S" boot. One to the breather tower and that braided hose to your aux air valve. On the other side of the aux air valve is a hose going to the plenum. The aux air valve is buried down under the right side intake runners for #s 1 and 2. You should be running all 1.9 FI and ignition parts.

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[Wildthings]

What is the hose set up that kind of parallel the coolant cross over pipe. I don't recognized it.

The hose set up is not in this picture of a 1.9L engine

[bluebus86]

if all else fails and you really want to be able to diagnois this van while running and have the ability to catch imtermittant problems in real time, then jnvest in one of the ecu mknitors that vancafe sells. this little unit is a great. very good for trouble shooting the injection system. you will need the digijet version.

http://www.van-cafe.com/home/van/page_1628_567/8691_shop_ecu_monitor_system.html


good luck
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022

[t3 kopf]

I had that same issue in the past when I had my 1.9l. A new AFM made my engine run poorly. 2 things fixed the problem. I completely rebuilt my injection harness and I added a restrictor to the oil breather line. The digijet system is pretty trouble free but the vacuum system has to be rock solid for everything to work correctly. The TPS switches are super easy to adjust correctly but don't usually contribute to this issue.
_________________
'90 Carat w/ '95 phase 1 EJ22 OBD2 conversion

[tjet]

Just a quick update on mine: with o2 sensor unplugged, I felt an overall drop in power once it warmed up, but it still had an intermittent stumble. This time, I happened to notice when it stumbled - right after I turned on the headlights & wipers. So maybe the alternator harness is bad & when there's an electrical demand, it's robbing the ECU power.

Here's a post for a similar running issue, which was caused by a bad alternator harness...

http://www.thesamba.com/vw/forum/viewtopic.php?t=618186&postdays=0&postorder=asc&start=0

[hdenter]

You're right Wildthings, I thought that picture looked fishy. I couldn't tell for sure just looking on my phone. I can't see the second port on the S boot.

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[jayinduluth]

According to the Bentley, that is a 1.9 air intake hose or boot.

I have possibly bigger problems. I took apart the AFM/filter housing so I could see the auxiliary air regulator better, in doing so I discovered that one of the hoses to the bottom of the vacuum shut-off valve, charcoal cannister was not connected. I connected it but noticed that the connector to the hose has a split in it. I must have knocked it off installing the AFM. So I put that back, assembled the AFM/filter back and like an idiot, thought I would go for a drive, because I guess I'm an eternal optimist. The drive around my neighborhood went fine, well, fine as in same symptoms, ok at the start, lacking any power from stop, but flooring it I would at least move and once it hit about 15mph, off to the races. I was able to floor it at least make it go up a hill, so I decided to take it out on city streets, got back to my hill (because Duluth is the san fran on the midwest...) to go my house, turned up said hill, got about two van lengths from intersection and it died. Tried to restart and it like its not getting gas. Some guy stopped. had me start it while he smelled the exhaust and said it was the fuel filter (which is new GW round one, between fuel pump and engine, installed last summer). I thought well, its probably not starting because I'm on an incline, but got towed up to my driveway, a relatively flat space and no start there either. Now I'm relatively disgusted and going to bed.
_________________
85 Westy with 91 2.1L

[Howesight]

[Tom Powell]

[jayinduluth]

Yeah I know, the smelling the exhaust and equating it to the fuel filter is a new one to me too. I do seem to have random people coming up to me and telling me what's wrong with my van.
I was in a bar a couple weeks ago telling a buddy of mine my van woes about going up hills, etc, random guy sitting next to us says its my catalytic converter and to disconnect it and that he's seen it lots of times.
_________________
85 Westy with 91 2.1L

[Tom Powell]

[Wildthings]

[Howesight]

Heard at a bar in Saginaw:

"Y'know them catalytic converters swim upstream to spawn every Spring, right?"
_________________
'86 Syncro Westy SVX