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will not idle

Moto Carlo

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Here is my sad tale.
I changed out the points for the mechanical advance tii distributor from IE. I had an impossible time doing the advance timing. Later I find that they had some problems with those Chinese distributors. So I took it off and re-installed my Bosche distributor. Turns out it was probably off an E21 due to the double vacuum inlets on the vacuum advance pod. I installed a Pertronix ignition (non vacuum advance - but was told it work work fine on this distributor not using the vacuum advance).

So it fires up and runs fine for about 1 minute.
Then even with all the feathering etc can not keep it running. Simply dies off. Often with a nice backfire through the carb (single side draft Weber) .

So I though - ok fuel delivery problem. So I took out my Revolution Relay (emergency / accident fuel pump off switch) . that I used with my Carter fuel pump. I was thinking... I had planned to replace this fuel line, so now is a good time. Fresh fuel line (no filter yet) runs to the carb from the pump. NO fuel filter no inertia switch or relay. Pretty straight forward. 

Fire it up... same deal . Runs for a minute then dies.  (I did also add a new Bosche blue col when I did the Pertronix conversion.

So I now feel I am chasing my tail a bit.
Before I remove the dizzy again and reinstall the old points as a test... any ideas?


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No sir. It has a manual choke. Weber 45 DCOE


Now an update. I checked the coil and the ohm resistance is 3.2 - so coil good.
Then I did re-install the points and static time the car.

Fired right up and runs well. So this takes the dizzy out of the mix.
But again after a minute it wants to die. Now, with the points it is not as bad. I can feather it and keep it going. Not backfiring.

So now I am thinking the carb. 

Any ideas why it would try to die after a minute?
This is a new carb and worked fine, but it did hesitate @ ~ 2k rpm.
So that is why I initially thought timing...


Ideas?  - float adjustment, jets, accelerator pump...?


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Thanks John.
That is the next step. I know from other cars that even new Webers can have the float not adjusted correctly. So that is the next attempt. Also the carter fuel pump pumps between 3 and 6 psi. Apparently these cars want 3 psi for single carb.
So also going to install a pressure regulator.

Gets a bit frustrating and always great to punt it off others to see if something un-thought of shakes out.

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7 hours ago, Moto Carlo said:

Turns out it was probably off an E21 due to the double vacuum inlets on the vacuum advance pod.

Don't E21 dizzys run backwards from those used on 2002s?


That being said...the fact that it'll run for a minute, then stall regardless of your fancy footwork on the accelerator does sound like a fuel problem.  Have you tried disconnecting the fuel line at the carb after the engine stalls, then cranking it over with the fuel line dumping into a catch can to see if it's pumping?  The problem could be something like an air leak in the fuel line that's causing slow or no fuel delivery after a minute or so of run time.  



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7 minutes ago, mike said:

Don't E21 dizzys run backwards from those used on 2002s?



I'm pretty sure they ran in the same direction up until September of 81 and I think that is also when they stopped using points/condensers.


Some 2002s came with the dual action pod.  I know the California '76 had them.  Not sure about the '75s.



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Bink! Now that is interesting.
My car is a 76 and does have the dual vacuum connection.
Also my cam has the #2 stamped up by the tdc mark (implys it is the original cam).
The serial number is 5794 1210610080  But it does not have that final #2 .
So ... perhaps this is a California cam, and that might change things.

Which makes me think the cam is de-tuned for emissions.
Which makes me think perhaps this is why I have been having a problem with the electronic dizzy upgrade.
Which makes me wonder if my Weber (aftermarket sidedraft) carb is jetted improperly for this cam,,,


What do you think? 


(Thanks Mike. I indeed did disconnect the fuel line at the carb  and saw a steady flow of gas fill my catch container. I also just replaced the entire fuel line and also made sure the vacuum line/ vent at the tank was clear.) 


(We thought the dizzy came from an early  E21, because of the double vacuum ports. And the fact it has been out of the car and re-worked at some point...but ...maybe original to the car.  ?)


Edited by Moto Carlo
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What is the number on the side of the distributor?

That will tell you what it came in originally.


The #2 cam on California '76 cars is not "de-tuned".  It is the same cam that came on all of the 2002s except the 49 state '76.


In order to assess the jetting situation, you might consider installing an AFR gauge.  Most of them have blinking digital displays, but if you shop around a little, there are also analog gauges that have a needle instead.


What problems are you having with the Pertronix?  (assuming that is the electronic ignition you've installed)


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JFU4 0231176084

So a tad confused here.
Mine is a 76 , and if it is not a "49 state" car , doesn't that mean it was a California car? Wasn't that a different cam in that car to try and comply with the new California pollution requirements at that time?
So I was thinking it had less power and perhaps could not handle the hotter dizzy. Maybe I have the nomenclature backwards.  ?


AFR gauge. Good idea. Never used one, but maybe it's time.


Yes sir; a Pertronix. Backfiring. Not idling long enough to do a proper timing.
Drop the old points in - no issue fires right up. Check my new Bosche coil ohm reading - fine a 3.2
Earlier I tried the IE mechanical advance electronic ignition. Got it timed at idle, but I had problems with the advance not advancing. Could not set the dynamic timing. (But I heard that was an issue with that product.)


The unique cam would seem to solve the riddle. But I do not know about it and assumed I did not have it.
So all ears here.


Thanks again for all the help!

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Based on that number the distributor you have did come from an e21.


As far as I know, the '76 California cam was no different than previous years.  The only "unique" cam was the #5 cam in the 49 state '76.  The difference, whatever it is, would not cause this issue.


Not sure what you mean by hotter distributor.


Did you eliminate, or bypass the resistor wire feeding the blue coil?

If not, you have doubled up on the resistance and you need to add another wire that feeds the full 12V to the internally resisted blue coil.


Problems can arise when you stack up resistance in the ignition system.  Resistor wire + blue coil + resistor rotor + resistor plugs and you get a weaker spark.



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Well, that is great info. So now I know the dizzy was added later. I will check on the resistor.  I am 90% sure I did remove that wire when I installed the new blue coil with the internal resistor. But I will double check. (I hope I blew it.  ? ) 


By hotter distributor I meant hotter spark. My take on the Pertronix (etc) is it gave a bit more hp by upping the sparking.


Well mine is a #2 cam. So that is that. But I will look into it and if it is different I'll let you know.

Also the afr is a great idea. I will look into that too.


Since I am having a bit of success with the old points, I  am now thinking my idling problem is fuel related. Next step is to put a fuel regulator on the fuel line and make sure it is only pumping 3. It might be drowning in too much fuel. Also the carb is coming off to check the float. I should have done that first thing anyway. (Kicking myself there.) With the Weber IDFs, the float is never set correctly from the factory.


(I'll revisit the Pertronix later.)

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14 hours ago, '76mintgrün'02 said:

Not sure about the '75s


The 75's with the Manual Transmission had Vacuum/Retard Pod on the distributor, the Automatic cars in 1975 were vacuum advance only.





75 US Emission.png


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1970 BMW 1600 (Nevada)



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2 hours ago, Moto Carlo said:

Mine is a 76 , and if it is not a "49 state" car


Other ways to tell if a '76 is CA or 49-state....is to look for the following:


Exhaust manifold-  '76 CA  (and all '75 cars) came with thermal reactors and EGR plumbing.  '76 49-state cars had no EGR.

Distributor- '76 CA cars (and all '75s)  had dual pod (advance and retard).  '76 49-state cars had vacuum advance only.

My '76 CA car (Manufactured in 9/75) has distributor model:  0-231-176-059  JFU4  (w/ vacuum advance and retard).

'76 49-state cars had dizzy model: 0-231-170-164  JFU4  (vacuum advance only). 


We should start a Bosch distributor directory.

This gets a bit tricky because the part numbers for BMW and Bosch are different for the same distributor.




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