Strange Idle

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gull
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Re: Strange Idle

Post by gull »

The timing plug is just there to keep crud from falling into the clutch housing, and to provide something for VW's special timing tool to fit into. You can safely run without it.

I'm in the Seattle area, but I have my hands full the next few weeks with my own cars and the upcoming Olympus Rally. If you don't get it figured out before then, though, maybe we can meet up and check it with my timing light and fuel pressure gauge.
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Briano1234
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Re: Strange Idle

Post by Briano1234 »

On Ron's Neo-Bentley site there are tricks, as well as www.cabby-info.com to statically set your timing using a VOLT/Ohm Meter. Ron and I have double checked them to be really really close....
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Re: Strange Idle

Post by VDubbinIt »

Gull - that would be great. If you could email me when you have time that'd be awesome. j.agtuca@gmail.com

I'm pretty sure the timing is close to correct but it's still not wanting to idle below 1100 RPM's.
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Re: Strange Idle

Post by PDX Cabby »

Don't worry about not having the plug... I've not had one since I got the gar... come to think of it, I don't think I've ever had one in any of my VWs...

1100rpm, while high, is still considered "acceptable."

The the engine warm up, and start checking for vacuum leaks. A can of carb cleaner sprayed on the intake joints, vacuum lines, and behind the injectors will tell you if you have a leak. IME, most of these older cars will have leaks at the injectors.

Here's my favorite way to time an 8v... thanks to Techtonics for putting it into pictures

1, Line up the dimple (on the right) with the hole in the timing plug. This cane be very hard to find, especially on some of the original flywheels
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2, Line up the dimple on the BACKSIDE of the camshaft to the front of the valve cover
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3, line up the #1 on the distributor, and tighten down just enough so you can still turn the distributor by hand, but won't turn on its own
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4, fire up the car, and turn the distributor counterclockwise (advancing) until things sound just right. For me this is usually about a quarter inch, putting me at 12-15degrees advance. A timing light can confirm that with the large diamond shaped marker on the flywheel.

Once you have the timing established, you can adjust the idle speed on the backside of the throttle body provided you DO NOT have a vacuum leak.
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gull
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Re: Strange Idle

Post by gull »

PDX Cabby wrote:1100rpm, while high, is still considered "acceptable."
If he's in the Seattle area, and the car is less than 25 years old, he'll have to get it to idle below 1050 rpm or they won't emissions test it.
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VDubbinIt
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Re: Strange Idle

Post by VDubbinIt »

That's good to know about the emissions testing. I have a year to worry about that though.
I followed all of those procedures for the timing and I'm 90% sure it's close. So I'm moving on from the timing... I'm thinking it's either a leak or a sensor. Here's what it does now:

Once it is warm it drives ok; my problem is with idling and starting

Morning:
Starts fine and will run for about 3 seconds at 2000rpms then die (unless I hold it for a few minutes) Then it'll fish until it hits about 80 degrees c
no accessories on it idles at 1100rpms
hit the brake pedal/turn the wheel/turn the lights on etc. it will drop to 900 ish and possibly die if these are all in conjunction without revving

Hot Start:
Starts fine and will die unless I hold it - you can actually hear the RPM's rev up once it's ok to let the accelerator go

Oh and btw, I'm a she
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Re: Strange Idle

Post by VDubbinIt »

gull wrote:If he's in the Seattle area, and the car is less than 25 years old, he'll have to get it to idle below 1050 rpm or they won't emissions test it.
And actually, it hit it's 25th this year! 3/86
No more emissions :)
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Re: Strange Idle

Post by Briano1234 »

Is your idle bypass o-ring leaking?
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Re: Strange Idle

Post by VDubbinIt »

Not sure, does brake cleaner work the same as carb cleaner for finding leaks?
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Re: Strange Idle

Post by gull »

It sure sounds like a vacuum leak. There may be other things going on, but "won't idle until it goes into closed loop, but runs OK when I push on the accelerator" is a classic vacuum leak symptom.

Look very carefully for loose hoses. I've accidentally knocked the idle control valve ones loose, and they can be hard to see nestled down in the manifold. Sometimes the PCV elbow on the intake manifold turns mushy and splits, too.

As Briano points out, the idle adjustment screw O-ring is a particularly sneaky spot that often leaks. If spraying your idle screw with carb cleaner makes the engine run differently, the seal's bad. If you can turn the screw with just your fingers, that's also a symptom of a bad seal. The O-ring both seals out false air and also keeps the screw from adjusting itself due to vibration.

You can also hit various hose connections and the fuel injector area with carb cleaner. If you hit a spot with a vacuum leak, the liquid will briefly plug it and the idle will change.

Pay particular attention to any hoses that cross the braided fuel lines. I've seen them saw right into rubber hoses before, and the leak is often on the underside, which is hard to spot.

Finally, because of the PCV system, a bad dipstick seal can sometimes cause vacuum leak symptoms. It has to be pretty far gone, but I've seen it happen.
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gull
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Re: Strange Idle

Post by gull »

VDubbinIt wrote:Not sure, does brake cleaner work the same as carb cleaner for finding leaks?
It should. All the liquid is doing is plugging the leak briefly. I've also heard of people using an unlit propane torch with the valve just slightly cracked open -- any leak will draw in the propane and the engine will run differently due to the richer mixture.
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eric4321
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Re: Strange Idle

Post by eric4321 »

I WOULD NOT use brake cleaner for finding leaks because it can be flamable! No telling what it could do if it does get in your engine. Also some will probably end up on the exhaust manifold if you are spraying the idle screw. Your car and your call but house brand carb cleaner is cheap at a parts store or Wally world.
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Re: Strange Idle

Post by gull »

eric4321 wrote:I WOULD NOT use brake cleaner for finding leaks because it can be flamable! No telling what it could do if it does get in your engine.
So is carb cleaner. If you have a really bad vacuum leak and hit it with carb cleaner you'll see some interesting white smoke from the exhaust. ;)
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eric4321
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Re: Strange Idle

Post by eric4321 »

I know carb cleaner will make interesting white smoke out the tail pipe but it is also made to run through an engine. I would not want to see what brake clean could do to the insides of an engine or have any drip onto the exhaust manifold. Like I said though your car your call. Carb cleaner is less than $5 a can though.
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gull
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Re: Strange Idle

Post by gull »

That's true, and if you're having idle problems you really ought to take a can of it and an old toothbrush and have a go at the accumulated goo in the throttle body and the airflow meter bore.
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