Question about suppressor coil on 1150 RT

[Kermit Jackson]

Hello,

 

I’m here daily but don’t post very often as I’ve been told (gotta love the parents) that I have two ears and one mouth so I should listen twice as much as I talk. Me being young in the BMW community I try to stay out of the way and glean the collective wisdom from this board and apply as necessary. This time I’m having no luck. After several days of searching numerous threads concerning coils and spark plug wires I have yet to discover if the ‘non-suppressor’ coil is a direct replacement for the suppressor coil on an 1150 RT. My 2002 1150 RT is NOT a P-RT yet has the suppressor coil. I understand that the suppressor coil was used on the P-RT models to reduce radio noise and BMW then used these coils in non P-RT production, as they were available/needed.

 

I know that the plug wires are coil specific so to change either is to change both. I have only seen a non-suppressor coil in photos and have never seen a good shot of the electrical connections. Has anyone had experience swapping a non-suppressor coil for the suppressor coil?

 

Parts fiche shows:

$200 for non-suppressor coil and wires.

$500 for suppressor coil and wires.

 

I am doing some diagnostic work on my bike and I think I may be replacing wires and/or the coil. I would rather not spend the additional 300 dollars for the difference in ‘non’ vs. suppressed coil if I don’t have to. I have no added electronics that require the noise suppression and I’m going to get rid of the bike in the spring. Any thoughts, comments, gottchas, horror stories?

 

Thank you very much for your time,

Kermit

[Ken H.]

They are a direct swap.

[Haynes]

Save the cash and go for the non-suppressor coil. If you have no communications on the bike, spending the extra $300 is out of the question.

[SWB]

They are a direct swap.

 

Maybe, and maybe not. This applies to the R1100RT & RTP, so the 1150 could be different. There are three coil options listed in the parts fiche for the 2001 R1100RT: non suppressed, suppressed, and suppressed "Official". I know that the wires on a non-suppressed version connect to the coil with a typical cap. (I purchased an after market Nology coil and wire set; works the same)

 

The "official" coil is contained within a metal box. The wires connect to the coil by stripping them, inserting the exposed core into the coil (words fail me in describing the compression fitting), and a retaining nut locks it in place. The dealer service writer told me that the three coils and wire set types are incompatible, but again, I haven't seen the civilian version suppressed coil and wire set, so I don't know how they attach. All I can say for certain is that absent some extra parts, the official/suppressed coil and wire set is not a direct swap with the non-suppressed set.

 

And yes, the suppressed coil and wire cost a bundle. Look for used replacements (maybe at bmwboneyard.com).

[SWB]

Save the cash and go for the non-suppressor coil. If you have no communications on the bike, spending the extra $300 is out of the question.

 

The Nology aftermarket coil and wire set is an optional replacement. It seemed to improve power and performance too (as Nology claims), but I have no way of proving that.

 

However, the Nology coil and BMW standard coil are about the same price (@ Chicago BMW), and the wires are affordable there too. If I had to do it over again, I'd have simplified my life, and gone OEM standard all the way from Chicago BMW.

[BUSTED]

Back when the R1100RT's first came out the stereo was standard equipment. I was having problems listening to ball games and other sporting events on trips, way to much engine noise, especially on am band. I complained to BMW and they replaced my coils/wires with RTP parts. Direct swap and made a real difference in radio listening!

[Kermit Jackson]

Thank you for the information. I have checked the resistance values on the coil. The primary is 0.5 as prescribed. The secondary is at 1420. The reference material I am using lists the desired value for the secondary at 1300. I was wondering if there is a ‘value range’ that is acceptable but not listed or is the 1300 value absolute? The upshot is that I’m getting fuel, air and spark but the bike will not start. I’m trying to not just throw money at it but to do diagnose as logically as possible going from the outside in. Prior to this that bike has been solid and is ridden almost daily as my primary transportation. The bike is a 2002 1150 RT with about 41,000 miles. Typical BMW maintenance schedule performed by me.

 

Since misery loves company let me give a synopsis of the ordeal and what I’ve diagnosed so far. Hopefully more experienced light may be shed upon the situation. It started just before Christmas while headed home from work. The day was bright, dry and clear with the temperature about 30 deg. I was on the interstate going about 85mph., 20 miles into my trip when as if a switch had been thrown my bike started running very poorly. Lose of power was immediate but the bike didn’t stop running. I started making my way towards the shoulder in anticipation of the bike stalling completely. The bike didn’t quit and I didn’t hear any associated metallic thrashing sounds so I thought being only 5 miles from home I would try to limp it there. I limped down the shoulder at 40mph to my exit about a mile away. Home is much better than being on the shoulder of RT95 during rush hour(s) traffic.

 

After getting off the interstate and into more sedate surroundings I did a few experiments. When I disengaged the clutch and rolled completely off the throttle the bike would quit running. When I would engage the clutch while rolling (in essence bump starting the bike) the bike would re-fire back to its poorly running condition. I was stopped at a few traffic lights and had to nurse the throttle quite a bit to keep the bike running. Finally, while attempting to get the bike up a snow covered slop into my workshop it stalled and I have since been unable to start it. All electrical systems appear to be up and functioning correctly. It does not appear to be an interlock problem. The dash and RID appear to be showing what one would expect to see in a normal functioning bike. The bike sputters as if trying to fire. I even had the bike to fire a bit when I was doing the injector test and fuel spray migrated into the cylinder through the injector hole.

 

So far:

Rearranged and reseated relays in fuse box. No change.

Fuel appears to be free of water or other contaminates. 16,000 miles on fuel filter.

Fuel pump sounds normal and each injector is delivering correctly patterned fuel spray. Have not checked fuel pressure since spray pattern looks ok.

Air filter not clogged. 4,000 miles on filter.

Recent vintage PC680 Odyssey battery. Voltage checks ok at rest and start load.

Spark at both cylinders. Verified by removing plug and grounding to exhaust and observing spark while turning engine over with starter. I’m not so sure that the spark is ‘fat and blue’, hence the checking of the coil. Not sure that it isn’t either. There is definitely a spark that is discernable in the florescent shop light conditions.

 

Next steps:

If the coil is not the problem I will probably look into the HES although it does not seem to fit the typical HES scenario. The weather was dry, the bike didn’t ‘just die’ and I’ve got both spark and fuel.

If the HES checks fine I’ll look at the fuel tank internals.

?????

 

Thanks for any suggestions,

Kermit

[Kermit Jackson]

In my previous post I forgot to add that if all else fails I'l look for a possible burnt valve. I've been trying to not say that out loud though...

 

Kermit