engine and drivetrain Ballast resistor, blue coil, black coil: questions, questions

[Buckeye]

I think my cay (76 BMW 2002, base model) is suffering from perhaps defective coil. Car runs fine for first 10-20 miles and then hesitation symptoms starts at steady speed (3000 RPM). The coil (“black coil” ??) seems original to the car as far as I can tell.

Here is the information stamped on coil bottom:

Bosch 0 221 119 016

624

KW 12 V

Here are measurements:

Coil (+) to (-) post is 1.8 ohms

Coil center post to (-) post is 13.22K ohms

Ballast resistor wire measure 1.2 ohms

Now, I searched the internet, this forum and even Bosch catalog and cannot find such Bosch coil part number anywhere. Any input to this mystery Bosch coil greatly appreciated.

 

Edit: added pictures

 

In picture #2, soild green wire crimped onto speaker wire like. Is that my resisitor wire?

Edited June 12, 2015 by Buckeye

[JohnS]

Buckeye,

  Yes, that wire that looks like speaker wire is the resistor wire.  On a regular (square taillight) 2002, it has roughly 0.9 ohms of resistance.  (it's hard to measure really small resistance amounts, so your reading of 1.2 ohms I would expect that your resistor is a 0.9 ohm one).  So if you choose to keep the resistor, then you need to use a coil that requires a 0.9 ohm resistor.  They used to be black, but don't assume that all black colored coils are the ones that need a 0.9 resistor.  The original coils on both of my tiis were black in color, but the sticker on them said they required a 1.8 ohm resistor.  Those tii black coils were equivalent to the "red" super coils.  BTW, the resistor wire (that looks like speaker wire) on a 1974 2002tii is twice as long as the ones used on the later model 2002s and therefore has 1.8 ohms of resistance. Hope that helps and doesn't confuse things more,

John

 

EDIT: I can check the Bosch part number for that coil when I get home tonight.  I have several of the coils that require the 1.8 ohm resistor and also a couple of the ones that require the 0.9 ohm resistor and can compare the Bosch part numbers stamped on the bottom of the coils.  Bosch part numbers are those 10 digit numbers stamped on the bottom.

Edited June 12, 2015 by JohnS

[Buckeye]

Thanks John!

 I won’t measure my resistor wire length, but understand the concept and it all makes sense.

 “Ballast resistance wire on a 1974 2002tii is twice as long as the ones used on the later model 2002s and therefore has 1.8 ohms of resistance”.

I am thinking will need to purchase Bosch 00010, 0 221 119 021, which I believe it silver canister with green label “use 0.9 ohm external resistor”, but like to have it confirmed and also to find out more about my existing coil. Seems very odd to me that I cannot find it anywhere. Greatly appreciate more information.

Buckeye,

  Yes, that wire that looks like speaker wire is the resistor wire.  On a regular (square taillight) 2002, it has roughly 0.9 ohms of resistance.  (it's hard to measure really small resistance amounts, so your reading of 1.2 ohms I would expect that your resistor is a 0.9 ohm one).  So if you choose to keep the resistor, then you need to use a coil that requires a 0.9 ohm resistor.  They used to be black, but don't assume that all black colored coils are the ones that need a 0.9 resistor.  The original coils on both of my tiis were black in color, but the sticker on them said they required a 1.8 ohm resistor.  Those tii black coils were equivalent to the "red" super coils.  BTW, the resistor wire (that looks like speaker wire) on a 1974 2002tii is twice as long as the ones used on the later model 2002s and therefore has 1.8 ohms of resistance. Hope that helps and doesn't confuse things more,

John

 

EDIT: I can check the Bosch part number for that coil when I get home tonight.  I have several of the coils that require the 1.8 ohm resistor and also a couple of the ones that require the 0.9 ohm resistor and can compare the Bosch part numbers stamped on the bottom of the coils.  Bosch part numbers are those 10 digit numbers stamped on the bottom.

[JohnS]

Hi Buckeye,

  Your 0 221 119 016 coil is the same as what is now sold as 0 221 119 021.  The Bosch part number was superceded from 0 221 119 016 ---> 0 221 119 021.  So you've got the right coil for your 0.9 ohm resistor wire.

 

http://www.boschcataloguessa.co.za/general_parts_catalogue/General%20Parts%20Catalogue%2002_2015.html#102

 

Hope that helps,

John

 

PS, no need to measure the resistor wire length.  The fact that yours is spliced onto that green wire tells me that it's one of the 0.9 ohm ones.  The tii 1.8 ohm resistor wire runs the entire length from the fuse box to the coil with no regular wire spliced in between the two.

Edited June 12, 2015 by JohnS

['76mintgrün'02]

Well, I suspect the coil in my ('76) car is original, but that's just because it looks old enough to be... 

The numbers are very close to yours

0 221 119 016

529

KW 12V

 

I am using an $8 meter, but the resistance numbers are as follows 

 

Coil (+) to (-) post .8 Ohms 

Coil center post to (-) post is 14 Ohms

Ballast resistor wire measures .8 Ohms

 

(Somebody put a little tiny capacitor (?) between +/- on mine.  Former query here labeled it insignificant).

 

 

Here is a Red 'Super Coil'

 

 

Coil (+) to (-) pos .8 Ohms

Coil center post to (-) post is 10 Ohms

 

Here is a 'Black' coil, recently purchased

 

 

Coil (+) to (-) pos .8 Ohms

Coil center post to (-) post is 16 Ohms

 

I am not sure whether any of this information is helpful...

 

Buckeye-- Have you tried taking your resistance measurements once it is hot and having problems, to see if the numbers change?

 

EDIT:  As suggested by Peterschop, I tried another meter, as these readings seem odd.  Those readings appear in post #30.

Edited June 13, 2015 by '76Mintgrun'02

[Buckeye]

Interesting!

No I have not measured anything with ignition on or engine running yet, but that is next step. Your car and mine are both year 1976 and the coil indentical. I like to think we both have original coil, but stange enough cannot find any info on this coil.

 

Shouldn't your readings be in K from (+) or (-) post to center post ?

 

Can you post more picture of you last coil (0 221 119 021)

 

Thanks

Well, I suspect the coil in my ('76) car is original, but that's just because it looks old enough to be... 

The numbers are very close to yours

0 221 119 016

529

KW 12V

 

I am using an $8 meter, but the resistance numbers are as follows 

 

Coil (+) to (-) post .8 Ohms 

Coil center post to (-) post is 14 Ohms

Ballast resistor wire measures .8 Ohms

 

(Somebody put a little tiny capacitor (?) between +/- on mine.  Former query here labeled it insignificant).

 

 

Here is a Red 'Super Coil'

 

 

Coil (+) to (-) pos .8 Ohms

Coil center post to (-) post is 10 Ohms

 

Here is a 'Black' coil, recently purchased

 

 

Coil (+) to (-) pos .8 Ohms

Coil center post to (-) post is 16 Ohms

 

I am not sure whether any of this information is helpful...

 

Buckeye-- Have you tried taking your resistance measurements once it is hot and having problems, to see if the numbers change?

['76mintgrün'02]

Can you post more picture of you last coil (0 221 119 021)

 

 

 

 

and the Red one just for fun

 

Edited June 12, 2015 by '76Mintgrun'02

[JohnS]

Old Bosch Number ---> New Bosch Number -- Use Ballast Resistor x.x

 

0 221 119 016 ---> 0 221 119 021 --- 0.9 ohm ( old ones were painted black )

 

0 221 119 050 ---> 0 221 119 030 --- 1.8 ohm ( old ones were painted red )

0 221 119 015 ---> 0 221 119 030 --- 1.8 ohm ( old ones were painted black)

 

Here's a picture of the original 0 221 119 015 from my '73 tii

Edited June 12, 2015 by JohnS

[Buckeye]

Thank you John S and '76Mintgrun'02 for coil cross references and pictures.

[peterschop]

I have just read this thread and it is making my head spin trying to process it all. I am reconsidering what I did to my car three years ago, a 1974 automatic. At the time I thought I needed a new coil because the car was cutting out after 15 minutes of driving and the coil was getting very hot. I would let the car cool off for about 20 minutes and it would start up again. I measured my resistor wire and came to the conclusion it was 1.8 ohms. I had read that the total of the coil and resistor should be 3 to 3.5 ohms.  I therefore bought a new Red coil (0 221 119 030) from AutohausAz. I figured 1.6 + 1.8 =  3.4 ohms. Afterwards, the problem still persisted. As it turned out, my Pertronix knock off was failing and needed to be replaced with a new Pertronix. Problem found and solved, or so I thought. 

 

My old coil was a Bosch Black coil and here are my readings.

 0 221 119 016

425

KW12V

coil (+) to (-) post  2.1 ohms

coil center to (-)  13.25K ohms

 

new Red coil

0 221 119 030

coil (+) to (-) post  1.6 ohms

coil center to (-)   15.2K ohms

 

 

My readings of the Black coil are close to Buckeye's readings. I am thinking that Mintgrun's readings are skewed as they seem low. Maybe it is time to buy a better meter.

 

 

I am now thinking I took a bad reading of my resististor wire. I just measured it again. First time I  got 1.5 ohms. Second time it was 0.9 ohms. The resistor part only goes part way to the fuse box. According to JohnS, that should be a 0.9 ohm wire. So, the Black coil with 2.1 ohms + resistor wire 0.9 = 3.0 ohms. But I now have a Red coil, 1.6 ohms + wire 0.9 ohms = 2.5 ohms.

 

Now according to Steven22, less ohms ohms = more spark but could also burn out my ignitor. So therefore I should be getting more spark at the risk of burning up my Pertronix.

 

Rolands post lost me as it does not have any data to back up the relevance of the pictures of different coils or any relation to the HD to alkaline batteries or spark plugs.

 

I think I will swap out my Red coil for the old Black tomorrow. I just hope the oil has not been boiled out of it.

Edited June 13, 2015 by peterschop

[Buckeye]

My resistance wire and solid green wire are crimped right about center of windshield area. My reading is 1.2 ohms, but I consider it 0.09 ohms because that resistance wire is crimped with another wire at coil connector, so I assume the other wire resistance of 0.1 ohms or so. Also it is good practice to touch voltmeter neg. and pos. together while meter is on and set on ohm. Subtract that value from resistance wire ohms value, and that should be actual resistance wire ohm value.
Isn't your reading between center to (-) actually 13.25K ohms on 0 221 119 016 coil of your per last picture?
Do you recall proximate resistance wire connection to green wire location on your car?

Edited June 18, 2015 by Buckeye

[peterschop]

You are correct, 13.25K ohms, my post has been corrected. The resistor wire is crimped to the solid green wire just before and below the driver's side windshield washer nozzle. I have a '74 and my coil is mounted closer to the firewall than on the '76's. I disconnected the resistor wire at the coil before measuring. I got a reading of 0.9 ohms and don't think the other wire connected to it has any effect on the reading.

Edited June 13, 2015 by peterschop

[avoirdupois]

Rolands post lost me as it does not have any data to back up the relevance of the pictures of different coils or any relation to the HD to alkaline batteries or spark plugs.

 

Relevance?    How about examples of "overhyped" advertising making marginal products seem superior ?

 

The marketing for the Bosch blue coil has not been particularly well articulated.It has often been described as "high performance" and "super."This brings to mind certain non-alkaline 9volt batteries that are labeled "Super Heavy Duty."Are the latter any better than the usually-more-expensive alkaline 9volt batteries?Are the more expensive platinum tipped Bosch plugs better than the standard copper core plugs?Marketing suggests they are but Toby may have a different opinion.

[Buckeye]

I forgot on 74 and previous model years coil mounted near firewall on passenger side and it make sense that resistance wire to green wire connection gets moved more to the left. Having similar reading on your resistance wire and mine I gather that BMW used same size and length wire on 76, (49 states) as 74 model year.

Thanks for chiming in and sharing your findings.

You are correct, 13.25K ohms, my post has been corrected. The resistor wire is crimped to the solid green wire just before and below the driver's side windshield washer nozzle. I have a '74 and my coil is mounted closer to the firewall than on the '76's. I disconnected the resistor wire at the coil before measuring. I got a reading of 0.9 ohms and don't think the other wire connected to it has any effect on the reading.

[billpatterson]

Hi Steve,

Thanks; I'll remove the ballast.

 

Much obliged,

-Bob

Hi there,

 

Thanks for asking the objective question, Bob. I too have been frustrated with similar posts and how they go off on a tangent and the question is answered but in a very verbose way. That aside, I have a blue coil in my '71. I reassembled the car using a blue coil vs. the original black. I did not know that the blue coil combined with the factory external resistor actually dropped the quality of the spark. The car has always run great but always seemed to start a little hard. After reading your post I decided to bypass the external resistor. VOILA...the difference was...well...instant (as it should be). The car fired faster and runs smoother. I thought it may have been due to being warm; so I waited to make my final decision by starting the car 24 h later with no gas pedal priming. It started instantly. I think this is improved the running of my car.

 

Regards,

Bill