MBMB

Should I have different left and right ignition coils ('89 GT)?

The left coil appears to have been replaced in '95.

The left has Bosch p/n 0 221 118 322 and the right has p/n 0 221 118 335. They have different #4 terminals, too (where the ignition cable plugs in):



Resistances are different as well:
Coil p/n primary secondary
Left (-322) 6 6k
Right (-335) 5 5.66k

PET5 lists a 944 602 115 00 Porsche part number for the coils up to '88, but doesn't list coils for 89+ cars. It also lists different part numbers for the left and right ignition cables, which leads me to believe that the left and right coils might, for some reason, be intentionally different.

But 928intl's catalog only shows one coil and one wire.

The Bosch coil catalog shows 0 221 118 335 as the correct coil for the engine. (The other p/n is listed for 928s from 1983 to sometime in '89 (but not the GT)).

A Google search for the right coil's Bosch part number turns up a post (on a Peugeot list) in which it is given Porsche part number 928 602 116 00 -- the part number shown in the 928intl catalog.

Googleing the left coil's Bosch p/n turns up cross-references to 944 602 115 00 -- the pre-89 928 coil part number.

I think, in researching my question, I've answered it. I'm thinking that in '95 the PO's mechanic replaced the left coil with an 85-88 coil (which required replacing the ignition cable).

So the next question is: what is the difference (other than connector shape) between the 85-88 coil and the '89-95 coil?

heinrich

From http://www.bosch.com.au/productcatal...ion_coils.pdf:

911 Carrera 83 - 94 930-20/25/26 6 3.2, 3.6L 0 221 118 322
924 S 85 - 88 M44.07, 08,09,10 6 2.5L 0 221 118 322
928 78 - 79 M28-03, 04 8 4.5L 0 221 122 001
928 S 83 - 86 M28-21, 22 8 4.7L 0 221 118 322
928 S4 86 - 89 M28.41, 42 8 5.0L 0 221 118 322
928 S4 89 - 91 M28.41, 42 8 5.0L 0 221 118 335
928 GT , GTS 89 - 91 M28.47, 49, 50 8 5.0, 5.4L 0 221 118 335

and

944 8V 82 - 85 M44-05, 06 6 2.5L 0 221 118 322
944 Turbo 85 - 91 M44.50, 51, 52 6 2.5L 0 221 118 322
944 8V 88 - M44.11, 12 6 2.7L 0 221 118 322
944S, 944S2 88 - 91 M44-41 6 3.0L 0 221 118 322
968 91 - 95 M44-43/44 6 3.0L 0 221 118 322

MBMB

Addendum -- Bosch has new part numbers. #00060 for the old 0221 118 335; #00055 for the old 0221 118 322. But Robert Bosch's website lists #00055 as the proper coil (two required) for the 1989 S4 and 1990 GT.

heinrich

ps a most excellent backdrop.

MBMB

According to the Bosch Australia coil catalog, some BMWs and Volvo 7-series of the era also used what is now designated the #00060 coil.

The questions, then, are 1) what is the difference between the #00055 and #00060 coils; and
2) what effect might running with one of each for 9 years / 20k miles have?

ViribusUnits

Do you know what the part number is on the final control units? There should be two of them, and i belive their part number should be the same, from 85-95, but I'm not sure, so. The 928 Intl. Catalog has one part for 85-95 cars. And it matchs the part number I found in the WSMs.

Let see if your part matchs the part number I have for the 85 cars.

Final tranzisterized ignition unit, Porsche Part Number

928.602.706.01

If it is, then the final units are the same, which means they should be able to power eighter coil.

The ignition rotors are the same, as are the caps, spark plugs, but the plug leads are diffrent. Thats kinda strange in my opinion. Is there something geomtricly diffrent that prevents the 85-85 wires from working on an S4? Or for that matter 89+

The EZK units are just about the same from 88 up, excepting the control chips. The 87 should be the same, except for the lack of dignostics and diffrent chips, and the 85-86 units should be the same, except for the vacuum instead of "load", lack of dignostics, and diffrent chips.

This is most strange.