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Here again for a bit of help...

Neoparoykos

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I am wrapping up a tune-up of the '72 Bavaria (new spark plugs, wires, condenser, rotor, distributor cap, coil, and points) and am having issues with it starting. :\

I installed everything, seemingly without issue, and following doing so it would not start. No issues prior to the overhaul. I smell fuel. Trying to diagnose the issue and I am leaning to a faulty condenser or failed wire from coil to cap.

-Spark plugs are gaped (seemingly) correctly: approx. .025"
-Wires are from Pelican (Karlyn)
-Condenser was OEM replacement part
-Rotor is OEM
-Coil is Bosch (silver/ bare metal with blue label)
-Cap is OEM
-Points are OEM and gaped to .014"

Any wisdom here would be helpful.

Additionally, I am wondering if the Petronix points replacement kit (here) will fit my car. It is noted to not fit the distributors with the round hole on the side, but I do not think it will actually prevent it from installation. Especially because the condenser I received (correct part number?) was also square unlike my round hole distributor.

Lastly, the issue may be the wire from my cable to the cap. The wire that came with my new wire kit does not have the additional white wire that goes I don't where (see pic)... I do not see this wire being available from BMW or elsewhere. Any sources?


BMW Coil Wire.PNG



Thanks for any help ahead of time!
 

Stevehose

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put your old condenser back in and check. If nothing then put your coil wire back in and check. Confirm your point gap is correct. Plug wires in proper order on cap? Wires to coil hooked up to proper + and - ? Do you get spark when holding plug wire to block?
 

HB Chris

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The circled wire is the diagnostic wire, NLA forever. Did you turn dizzy? I would double check point gap too. You have vacuum advance, check dizzy number, I wasn’t aware there was a version without advance.
 

Dick Steinkamp

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From your posts on Facebook, it sounds like this may be the first time you have replaced internal parts in a points type distributor. True? If so, it is likely the point gap was not set with the point rubbing block on the high point of the cam and the points are not opening or not closing. Another possibility is that the points are grounded through improper installation.

There are probably 10 other possible reasons why it won't start, but it's tough to diagnose long distance. It would probaby be best to have a friend experienced in this type of ignition system (doesn't have to be vintage BMW experience) come to the car and give you a hand.
 

Neoparoykos

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put your old condenser back in and check. If nothing then put your coil wire back in and check. Confirm your point gap is correct. Plug wires in proper order on cap? Wires to coil hooked up to proper + and - ? Do you get spark when holding plug wire to block?
I should ave mentioned I reinstalled all original parts (minus plugs and points) and it still did not start. Point gap is correct at .014" per Haynes manual. Plug wires are correct. Coil wires are correct. No spark when plug to block. No spark when coil wire to block either.

The circled wire is the diagnostic wire, NLA forever. Did you turn dizzy? I would double check point gap too. You have vacuum advance, check dizzy number, I wasn’t aware there was a version without advance.
Do you mean whether I turned the whole distributor or the rotor shaft? I didn't notice if the whole distributor is able to pivot.

From your posts on Facebook, it sounds like this may be the first time you have replaced internal parts in a points type distributor. True? If so, it is likely the point gap was not set with the point rubbing block on the high point of the cam and the points are not opening or not closing. Another possibility is that the points are grounded through improper installation.

There are probably 10 other possible reasons why it won't start, but it's tough to diagnose long distance. It would probaby be best to have a friend experienced in this type of ignition system (doesn't have to be vintage BMW experience) come to the car and give you a hand.
Hi, Dick. Thanks for following. Yep, first time. I did set the point gap with the block on the highest point. Possibly wrongly installed, but I actually didn't install the points until AFTER it didn't start.

I tried to go through the troubleshooting measures in the Haynes manual and it seems it may be narrowed down to the condenser (even though new) or the coil wire (to the distributor). Unfort the coil wire is NLA. :( Is it possible the ground on the valve cover could be influencing any of this? I powder coated the valve cover and the ground area was also coated. I attempted to scraped it off, but unsure if it is a sufficient ground.

So frustrated. In addition, I broke one of the heads on the bolts of the thermostat housing in hopes of using it as a ground.
 

E3_UK

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1. Connect a 12v test lamp (or multimeter) between coil + and an earth point on the block/chassis. Remove the cap and rotate engine to close points (just flick the starter a few times until the points are closed). Switch on ignition. If lamp doesn't light (or meter doesn't show battery voltage) then there is an issue with the ignition switch. This is an unlikely fault as the car was running before but it's always a good place to start.
2. Rotate engine to open points. Connect test lamp/multimeter between coil "-" and earth. Switch on ignition. If the lamp doesn't light or meter doesn't read battery voltage you have either a faulty coil or a short to earth inside the distributor (or from the wire between coil "-" and the distributor).
3. If "2" was a fail, to rule out the coil, disconnect the wire from coil "-" and switch on the ignition. If no lamp/battery volts then the coil primary winding has failed. If you get 12v then the coil is good. Proceed to "4" to check the distributor.
4. If "2" was a fail and "3" passed, this indicates a short to earth somewhere between coil "-" and the points. I'm assuming the wire between coil and distributor is ok so next check to make sure you have installed the points correctly with the insulating bush preventing the points from shorting direct to earth. I think this is your most likely problem, it's a common mistake to make if you're not familiar with points. If all checks out ok in this respect, move on to the next check.
5. Rotate engine to close points. Lamp/meter connected between coil "-" and earth. Switch on ignition. Lamp should not light, meter should read 0 volts. If you are getting a voltage here it could be, points not closing, points dirty, break in the points wire inside the distributor.

With ignition faults it is always best to just take a systematic approach to rule out each component in turn. I think you are most likely to have assembled the points with a short to earth, easily done. The ignition circuit is very simple, just a 12v feed from the ignition switch, passing through the coil then through the points (just think of these as an on/off switch) then to earth. If there are any short circuits to earth then current will not flow through the circuit and you will have no spark.
 
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Neoparoykos

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You don’t need that circled wire, no one has those anymore. See if you have voltage at the + terminal on coil with key on. What are you grounding on valve cover? There is no ground there.
Chris, thank you for the reply. That coil to distributor wire is coupled with another white wire. I cannot tell exactly where it leads, but it looks like it terminates at a spark plug & wraps around one of the wires with a weird terminal. It doesn't actually integrate with the spark plug wire, but terminates at it. The ground in question seems to run from the valve cover to what looks like a diagnostic port near the thermostat housing. I believe I checked for power at the positive terminal on the coil already and received 11.7 volts, but I will do so again.

1. Connect a 12v test lamp (or multimeter) between coil + and an earth point on the block/chassis. Remove the cap and rotate engine to close points (just flick the starter a few times until the points are closed). Switch on ignition. If lamp doesn't light (or meter doesn't show battery voltage) then there is an issue with the ignition switch. This is an unlikely fault as the car was running before but it's always a good place to start.
2. Rotate engine to open points. Connect test lamp/multimeter between coil "-" and earth. Switch on ignition. If the lamp doesn't light or meter doesn't read battery voltage you have either a faulty coil or a short to earth inside the distributor (or from the wire between coil "-" and the distributor).
3. If "2" was a fail, to rule out the coil, disconnect the wire from coil "-" and switch on the ignition. If no lamp/battery volts then the coil primary winding has failed. If you get 12v then the coil is good. Proceed to "4" to check the distributor.
4. If "2" was a fail and "3" passed, this indicates a short to earth somewhere between coil "-" and the points. I'm assuming the wire between coil and distributor is ok so next check to make sure you have installed the points correctly with the insulating bush preventing the points from shorting direct to earth. I think this is your most likely problem, it's a common mistake to make if you're not familiar with points. If all checks out ok in this respect, move on to the next check.
5. Rotate engine to close points. Lamp/meter connected between coil "-" and earth. Switch on ignition. Lamp should not light, meter should read 0 volts. If you are getting a voltage here it could be, points not closing, points dirty, break in the points wire inside the distributor.

With ignition faults it is always best to just take a systematic approach to rule out each component in turn. I think you are most likely to have assembled the points with a short to earth, easily done. The ignition circuit is very simple, just a 12v feed from the ignition switch, passing through the coil then through the points (just think of these as an on/off switch) then to earth. If there are any short circuits to earth then current will not flow through the circuit and you will have no spark.
Thank you for the lengthy reply! These are great steps that I can try. They may be similar to the steps attempted already as discussed in the Haynes manual. I will double check though. Thank you!
 

E3_UK

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I had concerns that it would not be appropriate for my system considering that mine includes vacuum advance. Is that true?
I just noticed on your link that it refers to non vacuum advance applications, not sure about this. Both mechanical and vacuum advance still work in exactly the same way, all this unit does is replace the mechanical switch (points) with an electronic switch. The advance is still controlled in the same way as for points. When I bought mine (Aldon Ignitor, basically the same as Petronix) there was no distinction between with or without vacuum advance.

The one I have is 1867A, it doesn't mention vacuum advance but I gave them the distributor serial no. and they advised the correct part. This is the same part in your link therefore is correct.
 
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Neoparoykos

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I just noticed on your link that it refers to non vacuum advance applications, not sure about this. Both mechanical and vacuum advance still work in exactly the same way, all this unit does is replace the mechanical switch (points) with an electronic switch. The advance is still controlled in the same way as for points. When I bought mine (Aldon Ignitor, basically the same as Petronix) there was no distinction between with or without vacuum advance.

The one I have is 1867A, it doesn't mention vacuum advance but I gave them the distributor serial no. and they advised the correct part. This is the same part in your link therefore is correct.
Thank you! I will give them a call and get one ordered as soon as possible. I hear the results are very positive with this product.
 

E3_UK

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Thank you! I will give them a call and get one ordered as soon as possible. I hear the results are very positive with this product.
Ask them about the reference to vacuum advance, I'm curious as to why it states this in the description. As I said I'm using this same item on mine with vac and never had any issues.
 

Dick Steinkamp

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I like E3_UK's test procedure in post #7. Approaching an electrical problem systematically is the best approach. Changing parts without knowing the root cause of the problem only introduces additional variables. When you get successful results to all 5 steps that E3_UK outlines, you will get a spark at the plugs. If you have not changed the timing, the car will start.

At this time, I would not introduce the variable of installing a Pertronix unit. The Pertronix unit is not a "silver bullet" to resolve a no spark condition. It is possible that after the installation of the unit you have exactly the same situation as you have now just with an additional expense and an additional variable to contend with (possible bad Pertronix unit).

I've used the Pertonix unit in several cars. I can't say the cars ran noticably better than with a new OE set of points with the dwell set properly (with a dwell meter..not with feeler gauges), but they do eliminate the need to periodically adjust and replace points.

If you want to change to a Pertronix unit, solve your ignition problem first.
 

E3_UK

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100%. At least with points you can easily perform the simple electrical checks, my procedure is from a 1960's Lucas fault finding procedure and can be performed withh nothing more than a 12v bulb and a couple of wires. Get it running first then fit the Petronix. I'm a bit on the fence with electronic ignition, I have it on some cars but not on others. If my ignition was to fail out on the road I'd certainly prefer to be running points, but it never has failed yet so I'm still on the fence :)
 

Dick Steinkamp

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One more hint.

One degree of dwell is equal to one degree of initial advance. Changing the dwell by one degree will change the timing by one degree.

I think your .014" point gap is equal to 38 degrees of dwell. It is impossible (IMO) to hit exactly 38 degrees of dwell setting the points with a feeler gauge. The car will run with a pretty wide range of point gap/dwell...it just won't run like it should. For example, the car will start and run with 48 degrees of dwell, but ignition timing will be off by 10 degrees.

After you get the car running, dial in the dwell with a dwell meter. On our cars, this is an interative process that can take several tries at adjusting the points to hit the dwell number. Once you have dialed in the dwell, you must retime the engine per the shop manual procedure.
 

dang

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So if I'm reading your comments correctly, you installed all new parts except for points and it did not start. You installed new points and it still did not start, then you reinstalled original parts (except for points) and it still does not start. This sounds like there's an installation mistake and not a faulty part.

Did you only remove and install parts without any other adjustments or work?

BTW, when I do this kind of work I don't trust my memory anymore so I take a bunch of photos with my phone before starting the work, wire connections, etc. It's been a life saver and I've referenced photos I've taken a year ago sometimes.
 

HB Chris

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Throw out the old distributor wire, that is just a sensor for the diagnostic plug mounted to front of valve cover. It just monitored the firing of that one plug wire, it isn’t needed and isn’t contributing to anything. It was only used by the dealer’s techguy. Check for voltage going onto the coil at the + terminal. The - terminal feeds the tach, if it is grounding out you will have no spark. And be sure the condensor you replaced that the wire isn’t grounding to the body of the dizzy, it hooks up to the points plate.
 
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Neoparoykos

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Thank you for all of the replies everyone! So...an update. I followed all of the advice above as best as possible and had some development. It now appears that I am getting a backfire from the carburetor. I think this is better than it was as it may indicate I am getting spark, but not sure how to resolve this problem. Seems that likely timing is the problem, but the only place I imagine this could have changed is the position of the distributor / rotor.
 

Dick Steinkamp

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Did any of the tests you performed from the #7 post result in any fixes? If so, which and what was fixed?

Have you ever removed the distributor or loosened the clamp at its base?

Are you sure the plug wires were put in the new cap in exactly the same position as they came out?
 
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