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Thu Dec 26, 2019 5:50 am

So my 2L FI Bus just does not start quick...It often drowns (smell it) after cranking ten times. The AAR and CSV both test good. Once running it is no problem at all. Runs smooth as butter. I have a new Optima yellowtop 55AH for starting so plenty of cranking power. So my suspicion goes to the spark.... Could it be weak. I have a retro fitted electronic ignition... e-spark (not pertronix)
So I measured the coil that came with it and it measures 3.1 Ohm in te primary circuit and 10,6k Ohm at the secundary... Seems to me kind of weak...
What is a strong coil producing?

Thu Dec 26, 2019 6:14 am

The resistance of your coil is normal. But that does not tell you anything about the high voltage performance of the secondary of the coil.

Check to see if you get a spark when cranking by laying a spark plug on the tinware connected to one of the leads from the distributor. If the plug sparks with a fat yellow spark then it is OK.
Avoid making the spark jump big gaps, it can damage the electronic unit by allowing the primary voltage of the coil to become very high.

If it is weak and blue then there may be problems.

Thu Dec 26, 2019 6:27 am

I find just the opposite to be true. I want a blue spark spark as a yellow one indicates a weak ignition situation.

This is the problem with the interweb, you’ll get conflicting information.

Thu Dec 26, 2019 8:39 am

A "blue spark" is a hotter discharge, showing a higher plasma temperature, and better ignition performance

It doesn't matter if someone else judges your spark temperature, you should look at it yourself and from a higher potential

Thu Dec 26, 2019 9:00 am

I'd put a distributor in that has points and see if that changes things. Every time the coil pulses it sends a signal to the ECU to make a spark. If your whatever kind of ignition you have is sending multiple sparks like a flood of them then the ECU is dumping fuel into the engine. There are a few systems out there that do that - instead of one spark they send a flood of them.

Thu Dec 26, 2019 11:35 am

kingkitesurf wrote: So I measured the coil that came with it and it measures 3.1 Ohm in the primary circuit and 10,6k Ohm at the secondary... Seems to me kind of weak...
What is a strong coil producing?
I don't give a lot of weight to coil resistance measurements, unless they're radically different (infinite ohms on secondary means windings broken; near zero ohms on primary or secondary, meaning winding shorted). I vote for trying points to eliminate any electronic ignition issues.

I find the best way to test a coil is on the bench in operation, where you can measure stuff and observe the spark across a wide gap.

Thu Dec 26, 2019 1:29 pm

also check your TS2. If the threads are corroded or it has failed it can cause an overly rich mixture although it is more common once it starts. Another issue could be a leaky or stuck injector. You might try some techron in the gas for a tank and see if it helps.

Thu Dec 26, 2019 2:20 pm

I think I revert back to points to see the effect Bill has rebuilt my distri. But I only placed electrical ignition in it afterwards. Although it has been running and starting great this summer driving over 4000 miles with the electronic ignition.
The injectors are all new from bus depot as well as their rubber seats. No leaks there.
The wiring FI harness is the only electrical old stuff still. The other harnesses have been renewed. I will also double check the aux air and to make sure the fuel pressure regulator.

Fri Dec 27, 2019 8:37 am

Quote: the coil that came with it
use the stock VW coil with the points too.

Fri Dec 27, 2019 12:42 pm

telford dorr wrote: kingkitesurf wrote: So I measured the coil that came with it and it measures 3.1 Ohm in the primary circuit and 10,6k Ohm at the secondary... Seems to me kind of weak...
What is a strong coil producing?
I don't give a lot of weight to coil resistance measurements, unless they're radically different (infinite ohms on secondary means windings broken; near zero ohms on primary or secondary, meaning winding shorted). I vote for trying points to eliminate any electronic ignition issues.

I find the best way to test a coil is on the bench in operation, where you can measure stuff and observe the spark across a wide gap.

Ditto that! Although me validating Telford on electronics is like ForestbGump validating Pauli on Quantum

I’ve found in modern coil on plug cars the four different circuits on two identical coils ohm out identically, and one works perfectly and other doesn’t

Fri Dec 27, 2019 12:51 pm

Abscate wrote: telford dorr wrote: kingkitesurf wrote: So I measured the coil that came with it and it measures 3.1 Ohm in the primary circuit and 10,6k Ohm at the secondary... Seems to me kind of weak...
What is a strong coil producing?
I don't give a lot of weight to coil resistance measurements, unless they're radically different (infinite ohms on secondary means windings broken; near zero ohms on primary or secondary, meaning winding shorted). I vote for trying points to eliminate any electronic ignition issues.

I find the best way to test a coil is on the bench in operation, where you can measure stuff and observe the spark across a wide gap.

Ditto that! Although me validating Telford on electronics is like ForestbGump validating Pauli on Quantum

I’ve found in modern coil on plug cars the four different circuits on two identical coils ohm out identically, and one works perfectly and other doesn’t

You have to reconnect all the coil pack wires before using the car Abscate. Just connecting one isn't the same as the old days - they all have a connector. :lol: :lol: :lol:

Fri Dec 27, 2019 7:46 pm

HEE HEE

:lol:

Tue Dec 31, 2019 12:25 am

So here is my finding.... I do not get 12v to the coil during cranking... hence no spark in the process. Obviously at some point it does and it fires up... then all is fine and 12v is supplied to the coil....
Where can this come from... could it be the litlle block in the steering column?

Tue Dec 31, 2019 12:54 am

kingkitesurf wrote: So here is my finding.... I do not get 12v to the coil during cranking... hence no spark in the process. Obviously at some point it does and it fires up... then all is fine and 12v is supplied to the coil....
Where can this come from... could it be the litlle block in the steering column?

Do you get something less than 12v or do you get no voltage at all.

Yes a bad ignition switch could not supply power to the coil while cranking but otherwise could work fine. Cheap part to replace. Buy an OEM part.

Tue Dec 31, 2019 1:16 am

Sorry there is 3V during cranking between the + and the - on the coil. That is not enough for a spark to come to live I guess. I replaced the ignition switch in the steering column but no change at the coil

Tue Dec 31, 2019 7:35 am

kingkitesurf wrote: Sorry there is 3V during cranking between the + and the - on the coil. That is not enough for a spark to come to live I guess. I replaced the ignition switch in the steering column but no change at the coil

is that with the electronic ignition or points?

Tue Dec 31, 2019 7:54 am

With electronic ignition. But this 2,8V exact between the + and - when running and cranking. The yellowtop shows 13,8 volts so that is super strong. The whole ignition circuit somewhere leeks voltage.
Just installed a new Bosch coil as well. No difference. So the ignition switch and the coil don’t make a difference.
Ground wire from the ecu connector #17 to coil is good (0 Ohm) and the wire from ignition on coil provides 13.8v with ground.
Can the double relay be faulty.

Tue Dec 31, 2019 8:57 am

kingkitesurf wrote: With electronic ignition. But this 2,8V exact between the + and - when running and cranking. The yellowtop shows 13,8 volts so that is super strong. The whole ignition circuit somewhere leeks voltage.
Just installed a new Bosch coil as well. No difference. So the ignition switch and the coil don’t make a difference.
Ground wire from the ecu connector #17 to coil is good (0 Ohm) and the wire from ignition on coil provides 13.8v with ground.
Can the double relay be faulty.

You need to know the voltage between the #15 terminal on the coil and the engine block when the starter is engaged.

Tue Dec 31, 2019 10:16 am

I don't know of any other threads here where people use that ignition system, and they have measured voltages. When the electronic ignition is closed it grounds the coil on #1. That drops the voltage across the coil between #1 and #15. The voltage you are getting may be normal for that system, or it may be a result of corrosion somewhere between the battery and #15. You can test the #15 circuit along its path to ground to see if there is any spot where it suddenly falls, showing that the nearby connector may be bad. On a points distributor that voltage is about 10V when the engine is cranking. In your system, both the electronic ignition, and the coil are pulling current. That voltage may be normal for the gauge of wire on a VW or it may not be.

Were it me, I would be measuring systematically - meaning between battery posts, between 12V+ post and ground, between 12v- post and ground, between the solenoid and ground, at the fuse block, at the ignition switch - basically looking to find where I was losing voltage.

That said - I can afford, install and maintain any ignition system made in the world for a fuel injected VW bus. I am running points simply because that is how the system was engineered and it makes my life a whole lot simpler. I run new old stock SMP blue streak heavy duty vented points and condensers, known to last a very long time between changes. I have yet to put enough miles on a bus at 1,500 - 3,000 a year to wear a set out. I also have boxes of new old stock Bosch points made when they were quite good, as well as any part that could wear out on the distributor on the bus. When I add up the hours people here with electronic ignitions troubleshoot their problems, and multiple by $100 an hour I charge my clients, I have saved thousands of dollars by just staying with points. Not everyone feels this way.

Tue Dec 31, 2019 11:17 am

SGKent wrote:
Were it me, I would be measuring systematically - meaning between battery posts, between 12V+ post and ground, between 12v- post and ground, between the solenoid and ground, at the fuse block, at the ignition switch - basically looking to find where I was losing voltage.

That said - I can afford, install and maintain any ignition system made in the world for a fuel injected VW bus. I am running points simply because that is how the system was engineered and it makes my life a whole lot simpler. I run new old stock SMP blue streak heavy duty vented points and condensers, known to last a very long time between changes. I have yet to put enough miles on a bus at 1,500 - 3,000 a year to wear a set out.

What counts for the ignition is the voltage between the #15 terminal on the coil and the distributor body (unless the electronic ignition grounds elsewhere). This takes any bad ground connections into account along with those on the supply side.

People really seem to fear ignition points. Pretty much my adage for decades has to buy quality points, install them correctly, and drive on. Sadly "quality" does not include today's Bosch points. :-(

Forty years ago, points were typically in pretty bad shape at 12,000 miles, but often could be filed to give another 6-12k mile, while today's one can double that number of miles if they want, as modern copper core spark plug typically fire at lower voltages lessening the damage to the points. Of note, points for many rigs are cheaper today than they were 40 years ago, so the cost of replacing points every few years hardly counts, also if you don't pull your distributor occasionally to service the points, you are likely not lubricating your distributor at the recommended service interval either, which can kill your engine's performance.