Coil has power, but no sparks flying with Digifant

[Bursch]

1986 Syncro, 2.1 L wbx with Digifant

We have plenty of experience on our Type4 powered T2 with L-jet and MegaSquirt but not with this system.

So the engine stopped running all of a sudden. Still turns over, but just won't start. After trying for a while, there is the smell of fuel, so for now assuming the issue isnt fuel related. The starter motor just turns and turns, and not even one hiccup or some kind of combustion going on.

When you turn the ignition on, coil is supplied with 12V. But hooking up the strobe nothing happens on either one of the HT leads when trying to start. Swapped out the original with a Blue Coil thinking it could be faulty coil, but none the wiser.

Removing the distributor cap everything looks oke with a green, brown/white and red/black running from the connector.

Where should I start looking or which parts do I need to swap out and try to see what the effect is?
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1978 T2b ASI Riviera Plan I // Camper Special with MegaSquirt & EDIS // 091 with 5.14 R/P and Peloquins LSD
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[MarkWard]

The quickest test is to try another coil. They do fail. If you don’t have a coil, next suspect would be the hall sender in the distributor or the three wire harness. Unplugged look for corrosion. Visually check the 3 wires in the distributor and the 3 wires in the harness. They do get brittle. You can bypass the hall for testing with a simple 12 volt test light connected to ground.
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[Bursch]

[MarkWard]

The method I use is to unplug the coil wire from the cap and set the end near a ground and the hall harness disconnected. I turn the key to run. With a simple 12 volt testlight grounded, I probe one of the outer wires of the harness then the center wire. Then the opposite outer wire back to center repeating this action. The coil should spark each jump. If it does, you’ve confirmed the harness, ECU, and coil are good and it’s a safe bet the hall has failed.

Also, you should verify the distributor is turning. It’s happened where the distributor has shifted up out of the engine case.

Disclaimer, I haven’t done this test on a digifant in a ton of years and I might be remembering wrong. I’m using a cheap 12 volt test light that looks like an ice pick with a single wire and alligator clip. It has a bulb, not an LED.

I also think the manual has a similar test described using a ground wire. The ECU fires the coil directly.
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[VicVan]

[Ahwahnee]

[DigiMatrix]

Sounds like the Hall sensor is working because it was noted there was a smell of fuel. The code in the ECU will not fire the injectors unless there are Hall pulses.

[crazyvwvanman]

Here is a way to prove the hall works, the injectors spray ok, and the coil makes sparks.

1. remove a screw on one side of the engine which holds an injector pair in the manifold. Pull out an injector pair.
2. pull the center wire out of the distributor cap and set the loose end on engine metal so any spark will jump to the metal.
3. remove distributor cap, rotate engine till the pulley timing marks line up AND the rotor points to the #1 mark of the distributor edge.
4. loosen the 13mm nut that holds down the distributor clamp bracket to the block. Leave the nut on just a couple threads.
5. lift up the distributor slightly and make sure the rotor now turns with your fingers.
6. turn on the key but don't crank the starter.
7. rotate the rotor by hand and you should hear the fuel pump run and see the injectors spray for each 1/4 turn of the rotor. there should also be a spark from the loose wire end for each 1/4 turn. careful!

Gas is flammable and injector spray mist perhaps more so.
Have a fire extinguisher and hopefully a friend standing by.
Be very careful!

Mark

[Captain Pike]

Brain dead.
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59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
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[Bursch]

[Bursch]

[ragnarhairybreeks]

Hi,

Not saying this is your problem, but my 2.1 suddenly stopped when driving and it turned out to be bad solder joint in ecu.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...u+alistair

Just a thought to keep in back of mind

Good luck

Alistair
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[crazyvwvanman]

Yes, pull the spark wire from the center of the cap that has 5 spark wires.

When finished with the test,

1. turn the rotor till it points at the mark on the distributor edge
2. push the distributor back down into place while rocking the rotor to make sure it engages fully into place. tighten the 13mm nut
3. put back the injectors and screws
4. put back the distributor cap and center lead

Mark

[tjet]

[crazyvwvanman]

Just need to set the end of the wire on engine metal and the spark if it is good and strong will easily jump the few millimeters to the metal while making a small pop sound.

Mark

[Bursch]