'77 Beetle FI Idle Issue

[ScottK66]

Fiddled around with the care some more today. At one point, I discovered that one of my spark plug wires came off. Got it reconnected, but it still didn't run right. Talking to the shop in Dayton, the guy told me that the plug was probably wet and needed to be cleaned or replaced. I assumed (am I'm learning not to assume anything with this car) that the plugs, wires, etc. had all been recently replaced. The problem is that I received no paperwork with it so I have no idea what's been done to it and what hasn't, where it's been or what it's been through. I decided to replace the tune up parts and got new plugs, wires, cap and a rotor. The old plugs were all carbon fouled and the one where the wire was of was wet with gas. The wires didn't look terrible, but the boots were discolored. Maybe that's just from heat from the engine, but it made them look old and questionable. The cap and rotor were probably fine, but I thought I'd replace them while I was at it. So, two of the wires route between the engine and the tin ware. It's a tight fit. How in the world do you pull them through without damaging them?

[Lost69Convertible]

Hi Scott. I assume the tight fit of the spark plug wires is for cylinders 1 and 2? (on the passenger side of the car.) If so, I find it's usually worth the time to remove the intake air filter box and the AFM when working on that side of the engine.
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[ScottK66]

[busdaddy]

You can pull the cup shaped boot off the end that goes in the distributor cap, them feed the wire through between the shroud and manifold from the outer edge, then put the boot back on and put it in the cap.
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[ScottK66]

[busdaddy]

RF-#1, RR=#2, LF=#3 &LR=#4 when viewed from behind. The #1 position on the cap is wherever the old #1 wire was, it's supposed to be over the notch stamped into the distributor rim, but not everyone puts the drive gear in correctly.
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[VW_Jimbo]

Because a picture is worth 1000 words!

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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[ScottK66]

Yes, that is exactly what I was looking for! I got my car back together and tried to start it. Cranked, but wouldn't start. Rechecked all my connections and made sure the cap and rotor were positioned and seated correctly. Still wouldn't start. Thought I had incorrectly gapped the plugs and started to take them back out. Now that I see the diagram, I realized a couple things:

First problem: I had misread Busdaddy's post and had the cylinder order flipped.

Second problem: Based on the diagram from VWJimbo, the notch on my distributor is in the #2 position, so if I follow the diagram rather that the notch location, that was also off.

Third problem (and possibly the worst): I had bought a new wire set and was having difficulty getting the #3 wire to go on the plug, but finally did. When I took it back off, I discovered that part of the insulator had broken off. I found one piece, but I think the rest of it is down in the well for the spark plug. I had removed the other three plugs, but not that one as I was afraid that if the piece of insulator fell down in the cylinder, I'd have big problems. I found an old hose for my shop vac, cut off the plastic nozzle end and tried to get the hose over the well in the hope that it would suck up the broken piece. No luck. Knowing what I know now, I probably don't have to remove the plug and I can put the others back in. I'd really like to get that piece out of there if I can though. A friend of mine has a borescope tool, so maybe we could use that to confirm if it's in there or not. I don't know how I managed to break it, but I'm sure it's something I must have done. The wires were only $15, so I'm not worried about the money. I'll buy another (and better) set. Once I get my mess straightened out, I'll try it again and see what happens.

[busdaddy]

Don't lose sleep over the stray bit of plug end insulator, it's likely down between some fins and harmless, even if it does fall into the cylinder next time the plug is out it's softer than any engine component and will get chewed up and spat out harmlessly.
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[ScottK66]

[ScottK66]

Okay, here's the latest. I got the new set of wires on and they are far superior to the first set I bought. They all fit snugly onto the plugs unlike the first set, which were wobbly after they were attached. I followed the diagram and hooked up all of the wires accordingly. Tried to start it and it cranked and popped a little but wouldn't start. As I had mentioned in my previous post, the notch on the distributor for the #1 plug is in the #2 position. That being the case, I took the wires loose from the cap and moved them all one position counterclockwise so the #1 wire is now lined up with the notch. Started it and it fired right up and ran great. I took it out and drove it about five miles without any issues. I don't know why the #1 position doesn't agree with the #1 position in the diagram. If the distributor were removed at some point, I would think it would have to go back in the same position or it wouldn't run right. Maybe the distributor is mis-marked from the factory. All I know is it runs again and is is running well for now. I won't ever assume that the problems are fixed. I now know better than that. The Beetle is the recovering alcoholic of my cars. We will take things one day at a time and hope there isn't a relapse. By the way, my friend stopped by with his borescope tool and I looked in the spark plug well for the broken piece of insulator. I don't know where it went, but I couldn't see it, so I'm not going to worry about it.

[busdaddy]

Good news!, fingers crossed for continued success.

That picture doesn't work with DVDA's, if the vacuum can is facing straight back like it should #1 ends up ~ 2:00.

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[Lost69Convertible]

Scott - If your Beetle has a relapse to fast idle after driving about 20 minutes (engine is fully warmed up), here's a quick test you can do. Pinch each of these hoses closed, one at a time:

If your idle slows down while pinching, you'll know the Aux Air Reg or Decel Valve is the culprit.
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[VW_Jimbo]

[ltjohnb]

[busdaddy]

Preferably not, as you mention a backfire needs to go somewhere, if it can't blow off a few hoses easily it might slam the AFM door shut so hard it breaks.
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[ltjohnb]

[Lost69Convertible]

Here's my thinking for what it's worth. I'm new at this compared to others, so you can weight it accordingly.

Backfires can damage the AFM --> Don't clamp the hoses: My Beetle had mild backfires on a regular basis before I reconnected the Decel Valve. And there was no AFM damage. So I think a big backfire must occur to damage the AFM. I'm not saying this to downplay the issue. Just want to share an observation.

Vacuum leaks cause problems with the FI system --> Clamp the hoses

It's a contradiction to me.

In the picture below you see my breather hose can slide out of the boot. I don't know if VW designed it this way or not.

So that's the compromise I settled on. I'm relying on the breather to pop out during a big backfire. And I clamped everything else.
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[busdaddy]

Better than nothing loose. Crack flappers are rare, but can happen, sometimes from a singular event, others from multiple little slams. Some have the relief valve in the door, others are solid, here's one with the valve that broke:

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[Lost69Convertible]

Busdaddy - I read comments about the AFM flapper relief valve only going into AFMs for the Porsche 912 and 914. And Beetle AFMs never had flapper relief valves.

Some say the Porsche engines were more likely to backfire. Others say VW just didn't want to add the expense of the relief valve.

What's your view on it?
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible