1980 vanagon...more AFM drama

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cegammel
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1980 vanagon...more AFM drama

Post by cegammel » Sat Jan 04, 2014 6:34 pm

Hi all,

I've lurked through most of the AFM info around here, and I'm coming up short... First off, my van is a bit of a Frankenwagen. I just got it, and I've done a ton of work to get it this far. Prior to my purchase of the poor beast, it was used and abused by multiple "it-don't-really-need-that" mechanics...that having been said, I'm missing several rather important parts (alternator, EGR assembly, thermostat assembly, etc.). Despite all, I got the van running pretty well for about two weeks. Taking that info into consideration, here's my current problem: The van starts right up and then dies...repeatedly. When I unplug the AFM, it starts right up and runs like a champ. The AFM has been tampered with; the screw heads are chewed all to pieces, and there's an end of a small black wire poking out. Visibly (to my untrained eye), the AFM seems to be functioning. The flap moves easily, and everything seems to twitch as it should when starting. The ohms are right on, as per the Bentley test.

My second guess was the double relay (and I greatly appreciate Colin's write up on this one). My relay, FrankenBits that she be, has a random 'jumper-looking-wire' running across two of the terminals on the red/black wire side (I don't remember which terminals...and it's dark out). Also, I'm missing the ground-to-screw wire entirely. Using the Bentley light test, the relay checks out.

So, my questions:
1) could I just have a 'bad' AFM?
2) Should I have any jumper wires from the red/black side of the relay?
3) Should the 1980 have a ground wire running from the 85 terminal back to the mounting screw?
4) Any other ideas as to what my problem is?

Oh, I've also just changed all of the vacuum hoses except the four main branch boots. I need to get those and get that done. There is a definite whistle upon starting, but I can't find the bloody leak anywhere...

cegammel
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Re: 1980 vanagon...more AFM drama

Post by cegammel » Sat Jan 04, 2014 7:06 pm

Oh, I should also mention that I've cleaned every ground that I can find (two on the rear of the van by the tail lights, one on the top of the engine, one behind the fuse block, the battery terminal, and the transmission attachment)...Did I miss any?

cegammel
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Re: 1980 vanagon...more AFM drama

Post by cegammel » Mon Jan 06, 2014 7:04 pm

So...no one has an answer for me? I've ordered a double relay, a fuel pump (to keep under the seat if nothing else), and a fuel pressure regulator, as it seems that bugger can cause weird AFM issues as well. Since everything tests OK, I think I'm to the point of replacing things until something works. I'm open to any and all advice here...

Interestingly, the local German shop guys wouldn't even talk to me about a VW...referred me to the clerk to order my parts myself...guess that old vans aren't as glamorous as Minis...

I also checked that 'jumper' wire on my double relay; it runs from 88y to 88z. Is it supposed to be there? It looks pretty original.

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Amskeptic
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Re: 1980 vanagon...more AFM drama

Post by Amskeptic » Mon Jan 06, 2014 10:18 pm

cegammel wrote: When I unplug the AFM, it starts right up and runs like a champ.
there's an end of a small black wire poking out.

double relay has a random 'jumper-looking-wire' running across two of the terminals on the red/black wire side
Also, I'm missing the ground-to-screw wire entirely.

There is a definite whistle upon starting, but I can't find the bloody leak anywhere...
Sorry I'm late. Where is my army of Vanagon assistants when I need them?

There is a red jumper from the hot lead of one relay to the hot lead of the other relay. Consider these the #30 terminals for each of the two relays under the common cap. One drives the ECU and AAR heater and injectors, the other drives the fuel pump.

The ground used to be a stupid brown wire under a mounting screw. Vanagons internalized the ground circuit I believe to the ECU. You MUST make sure all grounds are clean and secure. You MUST check all connectors, including the ECU, that each and every little "finger" or "tine" is in place in the connector. They like to get pushed down inside the plastic connector block, very subtle, when you are too damn sloppy stuffing the connector on. Check.

Can you turn on the pump just by moving the wiper inside the AFM when the ignition is on?
I'll answer in shorter time than this.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: 1980 vanagon...more AFM drama

Post by cegammel » Tue Jan 07, 2014 6:45 pm

I'll try the fuel pump / wiper turn on tomorrow. I know that the fuel pump shuts off after the van starts, but works right up until that point. Then it seems to run on residual fumes for a second or two. As for parts, I sort of figure that having a few spares of quickly disappearing things won't hurt, but I'd rather not plunk down $400 for a rebuilt AFM if I can avoid it. I should also check those ECU pins; I was pretty angry last time I slapped that sucker back on there.
Thanks for your help on this; I'm an impatient sort of person by nature, but I really have no reason to hurry. This van is definitely giving lessons in patience and humility...

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Re: 1980 vanagon...more AFM drama

Post by Amskeptic » Tue Jan 07, 2014 8:50 pm

cegammel wrote:I'll try the fuel pump / wiper turn on tomorrow. I know that the fuel pump shuts off after the van starts, but works right up until that point.
I'm an impatient sort of person by nature, but I really have no reason to hurry.
Especially check the delicate little contacts that close when you move the wiper. They are on copper stalks and are opened when the wiper parks. Carefully clean them. Pump must turn on when you move the wiper CCW and turn off when you let the wiper park. Good Luck.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: 1980 vanagon...more AFM drama

Post by cegammel » Wed Jan 08, 2014 3:06 pm

Amskeptic wrote:
cegammel wrote:I'll try the fuel pump / wiper turn on tomorrow. I know that the fuel pump shuts off after the van starts, but works right up until that point.
I'm an impatient sort of person by nature, but I really have no reason to hurry.
Especially check the delicate little contacts that close when you move the wiper. They are on copper stalks and are opened when the wiper parks. Carefully clean them. Pump must turn on when you move the wiper CCW and turn off when you let the wiper park. Good Luck.
Colin
I cleaned the inside of the AFM previously, including those little contacts, with no dice. I tried moving the wiper with the ignition 'on,' but no good on the fuel pump. So, I went ahead and swapped out the double relay, and she fired right up. Unfortunately, with all of the vacuum leaks fixed and the grounds repaired and cleaned, enough rattles disappeared for me to very clearly hear what I think is rod knock. I was really hoping we could get a couple of camping trips in before summer; if the rods are just tapping a bit, will I do serious damage by putting a few miles on it? It would be great to make it to summer break before I have to take the motor back out.

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Re: 1980 vanagon...more AFM drama

Post by Amskeptic » Thu Jan 09, 2014 7:56 am

cegammel wrote:swapped out the double relay, and she fired right up.

Unfortunately, I think rod knock.
if the rods are just tapping a bit, will I do serious damage by putting a few miles on it?
Although this is fuel delivery forum, and we are veering into a new category, please describe the immediate environmental variables surrounding this knock, i.e.

engine temperature
load at time of knock
duration of knock
aural frequency of knock, low thumps are main bearing-ish, tinny clatter is valve/rocker, soft murmer knocks are the aluminum pistons rocking in the bore and usually occur only when engine is cold, etc
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: 1980 vanagon...more AFM drama

Post by cegammel » Thu Jan 09, 2014 4:15 pm

May I start at the beginning? That way, you can see how big an idiot I really am...

I bought the van, destined for the scrap yard, with a detonated piston in the #3 cylinder, and a resultant mangled head. I took the engine out, swapped out the cylinders and pistons, put a rebuilt head on, and now just about everything else beyond the long block. Against the advice of people who know MUCH more than I do, I decided not to change the rod bearings, since the side to side clearances checked well within specs. When I got it running, one of the lifters was badly airbound. I took it to the local German auto guy, who immediately heard the lifter and called it a rod... I kept running the van, added some Marvel Mystery Oil, and that lifter quieted right down nicely. Then, this fuel thing happened, and I've been trying to figure it out since the beginning of December.

The original knock, which I am quite certain was lifter, was consistently loud and rhythmic (tock-tock-tock). I got out the stethoscope, but I was just unable to localize the noise any closer than 'very near the #2 cylinder, at the bottom of the pan.' Once that lifter quieted down, I now hear (and the mechanic may have heard this all along, I was focused on the lifter) a soft tapping that is not rhythmic and intensifies when I abruptly let off the accelerator. I can't really hear it from the driver's seat, only when I'm standing over the engine bay.

I have not tried getting the motor warm since replacing the fuel relay, so all I can comment on is engine cold, on a cold day (for GA). The knock is not apparent at idle, only when the accelerator is punched and released. I did consider piston knock as a possibility, but this sound does have the 'rattle-snake' quality that I've heard terrifying things about.

My oil pressure is great, by the way; consistently 35-50 psi from idle to slight acceleration. I'm fairly certain that the noise is not the mains, but I'm not sure of the cam shaft bearings.

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Re: 1980 vanagon...more AFM drama

Post by Amskeptic » Fri Jan 10, 2014 7:24 am

cegammel wrote:May I start at the beginning? That way, you can see how big an idiot I really am...
Nobody gets to call themselves "Big Idiot" around here except me, GODDIT? There's only room for ONE Big Idiot in this town.

Warm the engine up thoroughly. Drive as though it has a bad rod. That means keep the engine under load at all times, mostly acceleration loads, of course, but you can switch to deceleration loads too. We want to avoid free-running high rpms, which is what unavoidably happens at every shift, so shift at lower rpms than normal. Once engine is thoroughly warm, about 30 minutes of easy driving in cool Georgia climate, listen for sound before the engine has a chance to cool down too much. If the sound is less, you may have a piston with looser cylinder clearance than normal. This sometimes happens when you do a mix'n'match half rebuild/cobble together.

If the noise is slightly worse at this warm temperature, you may very well have a rod knock. I have a question either way: what determination was made that the grenaded #3 cylinder's rod was not bent?
Colin


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BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

aerosurfer
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Re: 1980 vanagon...more AFM drama

Post by aerosurfer » Fri Jan 10, 2014 11:54 am

Where in GA are you? If you are around atlanta, Im happy to give you another set of eye/ears, as well as recommend you to the guy I used who built my crank during my last rebuild.
77 Westy deluxe

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