Leon's Syncro build thread

This is my first time using the Syncro phone app…

Photos appear to load without resizing.

Next post I’ll try to load multiples

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Well there you go. 4 photos of a rotten coolant hose for your enjoyment

Wow, that hose is toast.

I lost a hose off my 2wd just above the air cleaner - well it split and dumped a pile of coolant over the engine very quickly when I was down the shops getting Chinese food.

I was surprised that the coolant actually got into the air cleaner from the hose spurting coolant directly above it.

There was about 50ml of coolant in the bottom of the air cleaner housing and I cant see a way that coolant gets in there - it looks all well sealed.

New hose and its all good after cleaning everything up from the messy/ sticky coolant.

My hose broke into 3 pieces once it was removed.







I managed to get the other end of the oil cooler coolant hose off (try saying that 3 times fast).

now to put the 2 new hoses on and fill with water to do a short engine run to catch the last of the thread chips in the old oil filter.

Wow that is extremely destroyed.

Amazing how long a bush fix often lasts though.





New dizzy cap, 02 sensor and hose installed.

Didn’t idle any better, so I turned the bypass on the throttle blade housing out about 1 turn. Idles strong at about 1100rpm, but importantly will start from cold and idle. And pulls down to 900-1000rpm when thermo fan and headlights on but doesn’t stall.

Little update.
Cold start this morning, started right up idled happily.
I’m about to take it work a short drive around the block and see how it drives and idles when hot.

Then I’ll change the oil and flush all the old coolant out and start the refill process. I’ve never done it before but it sounds tricky

Some positives I guess.
The coolant hoses I replaced didn’t leak. It didn’t over heat.
It didn’t set the low oil buzzer off, even though the aftermarket gauge reads pretty low at idle, sits on 35-50 psi driving around.
Still idles.

But it’s running super rich on petrol. I could feel it bogging down when accelerating and it struggled to clear itself, I could see black smoke when I was backing in the driveway.
Ran significantly better on LPG, but still had the odd stumble on acceleration.

A couple of weeks back I checked the timing at idle with the temp sensor disconnected, it was about 12-15° btdc so I pulled it back to around 5° made a white make at 40° and verified it advance to 40ish.
I thought at the time it had been advanced to make it run better on LPG.

Maybe the timing is too retarded now, but I feel it’s the digifant ecu thats crook.

Am I correct here, wide timing mark on front lip of pulley is TDC, small v mark on back lip of pulley is 5°btdc and the mark on the right is my calculated 40° from the 2 factory marks.

Try these instructions:
https://www.google.com/search?client=firefox-b-d&q=vw+t3+vanagon+2.1+mv+engine+pulley+timing+marks#fpstate=ive&vld=cid:54023597,vid:t7eficskDyk,st:0

They are very clear and made to suit the MV 2.1

Thanks Scott.

I’ve been testing the various electronics and found that the AFM has a worn carbon tracer.

With the multimeter hooked up it reads about 1300ohms closed and about 90ohms open, it does vary in between but is not a steady change and goes open circuit at the 1/3 mark where I can see the clear part of the carbon tracer.

I also found the fuse to the vent line heater was blown and the heater element reads 27 ohms at about 22°c and the book says 5-17 ohms at 25°c.





The ECU “looks” ok with no obviously burnt out components

If I can loosen the 3 screws that hold the carbon tracer board down and file a slot in the holes I could move the tracer slightly closer to the wiper arm and make a new path… But it feels like the screws have Loctite on them

Great work on all these issues Leon. Very impressive. Here is a great procedure I had found on Samba. I have it on my to do list to tackle the idle screw. Not ready to do the AFM as yet. Mine is reconditioned so should be Ok.
Here is the link:

Well worth a read.
Cheers, Peter

Thanks Peter, I found that Samba post about half an hour ago. I’ve already repositioned the plate to make a new path for the wiper.
After dinner I’ll put it all back together and run it tomorrow.
That post describes how to tune without the CO meter too

I’m starting to fantasize about retrofitting a carburettor.

Or an EJ25…

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With the AFM test method in the Samba post, I get constant voltage readings across the sweep with the occasional zero volts at the worn out patch. I can’t move the board any further, but I think it’s an improvement.

Tomorrow I’ll have a go at tuning the air bypass and anti tamper screw with this method.
I’ll verify timing again first.

Sounds like you are getting through a lot Leon, great work.
Carb’s have their issues also :slight_smile:
How are you reading the CO level for tuning?

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The method described in the Samba link uses the voltage output of the O2 sensor. It’s a bit crude but I think it will work.
I’ve already recorded all the starting positions, so if I make it worse I can go back.

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Well that doesn’t work.
Without the idle control valve powered up, it won’t idle at all and barely runs, because it’s so rich.

but with everything hooked back up it idles much better and I was able to close the idle bypass up and it now idles at around 900rpm. (Previously it would falter at that speed and eventually stall.

I think the improvement is because I repositioned the carbon tracer, the worn out spot is right at idle range. So previously it was getting no signal from the AFM at idle.

I’ll go for a drive and see how it pulls

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So, after some test drive tuning, I’ve got easy start, stable idle at around 900rpm.
Pulls reasonably well (not as good as when on LPG).

I tried bypassing the LPG Lambda circuit so only the digifant sees the O2 sensor. That seems to have improved performance under load.
I also experimented with some different AFM wiper positions and spring tension and made some noticeable improvement. I now have about half a turn of idle bypass and the anti tamper screw is just cracked open.

It starts idles and drives better than it has since I’ve had it.
But I still think it’s a bit under powered. I need to drive someone else’s to really tell.

I’ll see if I can cobble together a wide band O2 kit out of my parts and make a tail pipe extension so I can get a good idea of whats going on when it feels a sluggish.

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Great work! I had read that post in Samba before, but have never tried it myself.
As they note ideally you would have gas analyser (I’m not sure if there is anything economical you can buy/construct for this).
What I have found interesting is I have a few spares for the EFI. To test I have swapped them out on my engine to run for a while. I swapped out hte AFM, Dissy and idle control vale as a set. All have run fine.
However the tension in each AFM is different.
Never quite understood how that can be unless the O2 sensor is making up the difference.

On that note, if there a proceedure to test an O2 sensor (or know when it has failed)