Does anyone know the part number for the 928 seriese resister that goes between the power source and the coil?

One if mine is probably flacky. It gets so hot, I belive the paint on it or whatevere is starting to blister. I belive it's causeing my low voltage to the coil, which is causeing at least part of my miss. I'm NOT sure though.

I looked it up in the 928intl parts catalog, and it's 25 bucks!!! I thought no way, but it it. So I'm trying to see if I can find it anywhere else, hopefuly cheaper.

Thanks for the help.

 

Have you checked the connections to make sure they aren't corroded? Are they wired correctly? Both resistors should be in a series with the key on but only one (can't remember which) during crank. Have you ohm tested the resistor to see if it is in spec?

The 77-79 924's used the same type resistor, so you may find an identical one at the VW/Audi dealer. Older Plymouth/Chrysler cars also used ballast resistors so your local auto parts store may have an equivalent.

Dennis

 

If you mean the 4 & 6 Ohm resistors, I've got both. 046 905 109 and 046 905 109 A.
They're left over after the conversion. They worked just fine.
Let me know if that's what you're looking for.

Rob

 

Yea, one is bad for sure.

I tyred to ohm them out. One is about 1.2-2.0, the other about .8 or so. Basicly twice what their suppost to be. It's possible they where hot, and this might have effected the values, so they're not acting right. I'm going to ohm them out again, soon.

They are wired correctly.

The .4 one looks new, the other pretty heavly corroded. The new one I can get out and unscrewed any everything pretty easily. The other, well, the only way I'm going to be able to replace it is to cut the connecters, and crimp new ones on.

The .6 gets so hot it seems to be blistering the paint on the metal! Also, when I tryed to spray it with WD-40 to get the screws out, it started smokeing. Finaly, the WD-40 started bubbleing out of the seam between the metal band around the thing and the caramic cap on each end. I'm thinking it got too wet, with maybe some salt, corroded, and water got somewhere it shouldn't be, and screwed it up. Eighter that or something is semi-shorted, pulling too much current, and frying the resister. I don't have a clue how to tell which is which.

Is that a Porsche part number? Or a Bosch? Or (horrors!!!!) a VW part number? I called my local import parts house, and they couldn't figure out where it was from, much less what part it matches.

 

The part number is from PET and is also the same part number 928 Intl. uses.
If you look on the mounting tab, below the screw hole you'll find the mfgr's part number.
"Mfg BERU, W. Germany WZR04K" and "BERU, W. Germany WZR06K" respectively.
They are described in PET as "series resistance green, OHM 0,4" and "series resistance red, O,6", with same part number from 78-86 on both USA and Euro.
Here's a picture

<img src="http://mywebpages.comcast.net/robmb/P0000148.JPG" alt=" - " />

Rob

 

Sounds like excessive current draw to me...I'd be questioning the Ignition coil for possible primary winding breakdown...If you have a spare I would try that first...Good Luck Bill 84 928s

 

I don't have a spare coil. At 50, or so, bucks a peice, thats awful high cost, unless I'm pretty sure what the problem is.

I tryed to check the coil a while back, and it ohmed out OK. I'll try it again. The coils not old.

Hum.

Any way to check it with a multi meter? Thanks.

 

There is one other possibility that could contribute to your problem and that is voltage low at source...Lower voltage = higher current drain therefore increasing the temperature of the resistors..Resistors will change in value and they normally go high when damaged...you may have a duel problem here ...(1)resistors damaged by excessive current drain (heat).....
2..Voltage low and or high current draw problem...
The resistor high values you posted could have been there for quite a while, measure them cold and then again after they have warmed up...caution
no power to circuit or you will damage your multi meter...your diagnosis could very well be spot on
with the problem being the .4 and .6 resistors. My concern would be why? they changed value and what? is causing the issue...Good Luck I hope this helps...I have to head off to work, talk to you later... Bill 84 928s

 

With the resisters off, they are getting almost exactly 12 volts to the first resister. Like 11.99. When I do this test, the engine is off of course, but the key is "on".

On the back side of the last resister, I've got but like 6 volts going to the coil. Again, engine off, key on.

Coil ohmed out properly, IIRC. I'll do it again in the not so distant future.

I have a question. When the TUZ brain wants the coil to fire, does it connect the ground for the coil to the ground, OR does it disconnect the ground for the coil. If it connects the ground, that would explain the low voltage when I hit 4,000 rpm, followed by engine missing.

Thanks for the help so far.

 

Just for the heck of it, with no voltage present, check the wire connections to the ignition coil...your resistor should be attatched to the terminal with the highest ohm reading. To explain, use your ohm meter and connect to the HV point on coil and look for a reading to the screw terminals on either side . The higher resistance should go to the resistor side. That is according to the drawing..I wonder if the coil is backwards...Just a thought..good luck Regards Bill 84 928s

 

Hey Viribus...How are you making out? Just wondering if you are any closer to an answer. Just curious..Which resistor gets very warm the .4 or the .6 ?...Bill 84 928s

 

Mid terms are this week for me. Organtic Chemistry II already ate my lunch, and I'm afraid Thermo might too, so I don't have much time for this. Historicaly, mid terms haven't been so hard for me, but this semester is kicking my rear.

Can you put a coil in backward? I didn't think it was possible, but now that I think about it, I guess you could.

If I'm reading the wireing diagram, the resistance from one 12V termonal to the other should be the same, but the resistance from the coil wire termonal to the + termonal should be lower than the - termonal, right? Unless it's marked. I forget.

The .6 get way over hot.

 

You got it OK..I think ...If I'm not mistaken I think the neg is the transistor ignition.. positive should go to the resistors..sounds like you have a diagram and if yours is marked like mine..(1)is transistor ignition..(15) is positive 12v...(4) is High Voltage to Distributor.
So with your ohm meter you should have a higher reading between 4 HV and 15 positive than 4 HV and
and 1 Negative...(1) is therefore your common post ...I hope I'm not confusing things here. I think you have a good grasp on what is going on there,so on that note I'll stop and good luck with your midterms..Regards Bill 84 928s