1994 R1100RS cold start issue

[Ralph1212]

Hi everyone,

 

My RS is running much, much better since I added the AF-XIED, upgraded the injectors, checked the TB sync, BBS settings and idle.  It's like a different bike.  

 

(Fyi: The following is done in a garage with a fan blowing air over the cylinder heads and oil cooler)

 

The problem is with the cold start.  I have to press the choke lever to START and crank the engine for about five seconds until the engine starts.  The rpm is around 1500-1700.  I then need to hold the choke lever in that position until one, ideally two, bars are on the oil temp gauge.  If I release the choke lever from START to ON too soon, the rpm drops to <1000rpm and is likely to stall.  (The battery is a new AGM, but if it stalls too soon after the cold start, I have to put it in the charger; I need to check if this is a separate issue.)

 

Once the bike reaches four bars on the oil temp and the rpm climbs toward 2000, I can switch off the choke lever and the engine idles steadily between 1000-1100.  I have no problems restarting the engine once it's warmed up.

 

I cleaned the TBs with spray cleaner.  I know I'll probably need to give them a more thorough cleaning in the off-season.

 

Any suggestions on what might be going on with the cold start?

 

Thanks,

Ralph

[roger 04 rt]

Can you measure the TPS voltage between pins 1 & 4 with the “choke” in the mid, detent position?

 

It should be 800-900mV. 

[dirtrider]

1 hour ago, Ralph1212 said:

Hi everyone,

 

My RS is running much, much better since I added the AF-XIED, upgraded the injectors, checked the TB sync, BBS settings and idle.  It's like a different bike.  

 

(Fyi: The following is done in a garage with a fan blowing air over the cylinder heads and oil cooler)

 

The problem is with the cold start.  I have to press the choke lever to START and crank the engine for about five seconds until the engine starts.  The rpm is around 1500-1700.  I then need to hold the choke lever in that position until one, ideally two, bars are on the oil temp gauge.  If I release the choke lever from START to ON too soon, the rpm drops to <1000rpm and is likely to stall.  (The battery is a new AGM, but if it stalls too soon after the cold start, I have to put it in the charger; I need to check if this is a separate issue.)

 

Once the bike reaches four bars on the oil temp and the rpm climbs toward 2000, I can switch off the choke lever and the engine idles steadily between 1000-1100.  I have no problems restarting the engine once it's warmed up.

 

I cleaned the TBs with spray cleaner.  I know I'll probably need to give them a more thorough cleaning in the off-season.

 

Any suggestions on what might be going on with the cold start?

 

Thanks,

Ralph

 

Afternoon Ralph

 

Do what Roger requests if possible.

 

You also  might be able to pin it down somewhat by removing the #5 fuse for about 30 minutes then reinstalling the fuse. (then see how it starts & idles the next morning's start) -- If this makes a difference we can go from there.

 

Next, try disconnecting the  AF-XIED then see how it cold starts & cold idles. (this might also point a finger).

 

If your system (battery) voltage is so low after a cold start that it won't restart then you might have poor spark, low fuel pressure, & low injector spray right after cold start. So maybe try jumping from your car or other motorcycle during & after cold start.  If the jump makes it start & cold-idle better then that will also tell us something in that area.

 

Your 94 1100RS is kind of an outlier as the CCP coding is factored in by harness wiring not a removable CCP.

 

Could be o2 sensor related but the   #5 fuse removal for about 30 minutes should eliminate the o2 learning influence on starting.

 

 

[Ralph1212]

Hi Roger: I have a multimeter; I'll have to look up the info for how to access those pins.

 

Hi DR: I can unplug fuse #5 later today and see what happens; the engine will be cold.  Is the unplug to be done while the engine is off or running?

[dirtrider]

3 minutes ago, Ralph1212 said:

Hi Roger: I have a multimeter; I'll have to look up the info for how to access those pins.

 

Hi DR: I can unplug fuse #5 later today and see what happens; the engine will be cold.  Is the unplug to be done while the engine is off or running?

 

Afternoon Ralph

 

Key-off not running/ 

[Jim Moore]

I like to keep my rpm around 1200. I think it idles better and comes off the bottom with more snap.

[Ralph1212]

3 hours ago, roger 04 rt said:

Can you measure the TPS voltage between pins 1 & 4 with the “choke” in the mid, detent position?

 

It should be 800-900mV. 

 

Roger, can I measure the voltage with the ignition on/engine off?

[roger 04 rt]

Yes

[Ralph1212]

I decided to do the easiest thing (suggested by DR).  I pulled the #5 fuse to the Motronic for about an hour (only for this long because I was eating dinner; for future reference, does anyone know how long it takes for the Motronic memory to clear?)

 

This seemed to have the desired effect.  I used the same start procedure (thumb on choke lever to full START position; engine cranked for three to five seconds before turning over.  RPM was around 1700.  I released pressure on the choke until I my thumb was off it; the RPM settled down to just above 1000 and was idling steady. As the oil temp went to two and then three bars, the idle started climbing towards 1500-1700 and I started dialing back the choke until it was fully off and the tach was at 1100.  This is the smoothest cold start I can recall.  No idea if pulling the fuse will become a recurring task.

 

Roger, I wasn't able to determine the voltage reading between pins 1 and 4 on the TPU

 

Ralph

[dirtrider]

7 hours ago, Ralph1212 said:

I decided to do the easiest thing (suggested by DR).  I pulled the #5 fuse to the Motronic for about an hour (only for this long because I was eating dinner; for future reference, does anyone know how long it takes for the Motronic memory to clear?)

 

This seemed to have the desired effect.  I used the same start procedure (thumb on choke lever to full START position; engine cranked for three to five seconds before turning over.  RPM was around 1700.  I released pressure on the choke until I my thumb was off it; the RPM settled down to just above 1000 and was idling steady. As the oil temp went to two and then three bars, the idle started climbing towards 1500-1700 and I started dialing back the choke until it was fully off and the tach was at 1100.  This is the smoothest cold start I can recall.  No idea if pulling the fuse will become a recurring task.

 

Roger, I wasn't able to determine the voltage reading between pins 1 and 4 on the TPU

 

Ralph

 

 

Morning Ralph

 

I will default to Roger on how this is effecting or interfaces with the AF-XIED.

 

I will only address the possibility of your o2 sensor effecting the Motronic adaptives (learned fueling offsets from the o2 sensor).

 

If you STLL have an old (or original) o2 sensor in that bike then that could be causing your Motonic to learn improper adaptives. (if you still have an old o2 sensor you might want to install a new one just to have a clean "known" starting point)

 

By removing fuse #5 you are causing the Motronic to loose/reset it's learned adaptives.

 

As far as time  for #5 fuse removal (a guess would be 3-5 minutes at most), I usually request a longer removal just to be absolutely sure that the Motronic clears it's adaptives when troubleshooting.  

 

Added: having 2 people working with you on this somewhat complex problem can get confusing & send you in different directions. Seeing as Roger is the  AF-XIED guru I will back out of this thread so he can work with you.

 

If I have something small to add I probably will (briefly) but Roger is the one to work with on this if possible.

 

 

 

 

[roger 04 rt]

I’m not around much for the next week. To me this problem sounds unrelated to the AF-XIED. I would work on the cold start problem with the AF-XIED either removed or if that’s too hard due to splicing it into the cable, dial the AF-XIED to setting 1. 

 

The thing to to figure out is, is the fast idle lever opening the throttles enough or is it fuel delivery related or is it ignition? I suggested measuring the TPS because it is usually easy. The other thing you can do is make sure both throttles are coming off the stops by 30 thousandths or so when you put the fast idle lever in the mid position. 

[Ralph1212]

I've spent some time reading about the Motronic 2.2 ECU, mostly on largiader.com.  

 

The 2.2 doesn't have a "learning mode", unlike the Motronic 2.4 ECU (available in the R1150xx).  You can pull the #5 fuse and reinstall after a few minutes, turn on the ignition and cycle the throttle from closed to full open twice to "teach" the throttle range to the 2.2 (though I think there is some disagreement over this.). My '94 (manufactured in 6/93) definitely qualifies as a "beta bike"; not even having the electrical slot to accept a CCP.

 

I would prefer to not disconnect the AF-XIED since the bike has been running so nicely with it.  I can dial it down to 1 and go from there.

 

Roger, you've been a big help already.  No worries.  If I had some sort of tutorial on testing the TPU, I would get it done.  The best thing I saw was a youtube video for testing the TPU on a car.  There's a serious lack of electrical troubleshooting information available.  But maybe I'm looking in the wrong places.  I can guarantee, the throttles are not hyper-synced to a tolerance of 30 thousandths.  I certainly don't have the tools to find out.

 

Aside from questions with the cold start, the bike has put a smile on my face every time I've taken it out since the mods.  I'm very proud to own it and plan to be it's owner for a very long time.

[dirtrider]

51 minutes ago, Ralph1212 said:

I've spent some time reading about the Motronic 2.2 ECU, mostly on largiader.com.  

 

The 2.2 doesn't have a "learning mode", unlike the Motronic 2.4 ECU (available in the R1150xx).  You can pull the #5 fuse and reinstall after a few minutes, turn on the ignition and cycle the throttle from closed to full open twice to "teach" the throttle range to the 2.2 (though I think there is some disagreement over this.). My '94 (manufactured in 6/93) definitely qualifies as a "beta bike"; not even having the electrical slot to accept a CCP.

 

I would prefer to not disconnect the AF-XIED since the bike has been running so nicely with it.  I can dial it down to 1 and go from there.

 

Roger, you've been a big help already.  No worries.  If I had some sort of tutorial on testing the TPU, I would get it done.  The best thing I saw was a youtube video for testing the TPU on a car.  There's a serious lack of electrical troubleshooting information available.  But maybe I'm looking in the wrong places.  I can guarantee, the throttles are not hyper-synced to a tolerance of 30 thousandths.  I certainly don't have the tools to find out.

 

Aside from questions with the cold start, the bike has put a smile on my face every time I've taken it out since the mods.  I'm very proud to own it and plan to be it's owner for a very long time.

 

Afternoon Ralph

 

Looks like Roger is going to be busy (if he returns I will go away)

 

Careful what you read as there is some incorrect info on the internet.

 

The BMW Motronic 2.2 (basically 1100 era) does NOT have a TPS learning  (Throttle Position Sensor) learning mode--- (on the Motronic 2.2  you get what YOU set).

 

The Motronic 2.2 does have rudimentary  adaptive fuel  learning & gets that mostly from an active o2 sensor.      

 

When Roger is talking about .030" that is how far the choke (fast idle) lever should open the throttle arms off of the base idle screws with choke on. He is trying to have you determine IF your choke (fast idle) lever/cable is set somewhat  correctly.

 

 

Not the best approach  but_______________

If you find that you don't want to mess with the AF-XIED or try a new o2 sensor then you could--- remove fuse #5, then install an in-line fuse with a relay that replaces the removed fuse,  then power that relay's pull-in coil  from an ignition-key-on circuit that  goes open at key-off, then re-energizes at next key-on (that will delete the Motronic adaptives at every key-off same as removing the #5 fuse each time)  

 

Before even considering something like this be sure to remove fuse 5 a few more times to verify that it is having the effect  on cold start that it did the first time.

 

One other thing to consider is  that if your bike is a used bike, then make sure one of the pervious owners didn't cut the CCP coding wire to force it to run open loop (some 94RS riders did that) .  

 

 

[JamesW]

Hi Ralph.  My '93 RSL exhibited the same hard starting phenomena as yours until I learned a somewhat different starting procedure.  Basically what I do is not use the choke control at all ever.  Instead I give the bike a slight amount of throttle then crank the engine for about 3 seconds while holding the throttle open a slight amount.  Then I pause cranking for about 2 or 3 seconds then crank again while opening the throttle the same slight amount and she starts right up.  You might have to experiment with the amount of throttle applied for this procedure.  I think, if I remember correctly, it was DR who told me of this starting procedure for the very early oilheads.  I even removed the choke cable since using the choke results in a throttle body out of sync issue which isn't necessarily a deal breaker but I just don't like the roughness which results and what you have to do with the throttle to get the TBs back in sync.  Just don't need the choke and all it really is is a throttle positioner anyway.  All this nonsense later went away thanks to the Bowden box on later bikes.

[Ralph1212]

Hi James,

 

I just tested this procedure on my RS and it actually started on the first three-second crank.  But it won't stay running without continued throttle input.  Otherwise it stalls out.  Is this your experience as well?  I could see using this procedure and then dialing in just enough fast idle with the choke lever to keep it around 1000 rpm while it warms up.

 

I prefer letting the engine get up to four bars on the oil temp before I ride off.  I had some frustrating experiences last year when I rode off too soon.

 

I have a fan blowing over the hot parts and there's no lower fairing parts to melt.

 

Ralph

[Ralph1212]

On 8/15/2019 at 11:18 AM, roger 04 rt said:

Can you measure the TPS voltage between pins 1 & 4 with the “choke” in the mid, detent position?

 

It should be 800-900mV. 

 

The reading is approximately 685mV.

[JamesW]

Hi Ralph,  Yeah mine will stall unless I keep the throttle turned up after start.  Remember, I don't use the so called choke.  Actually, I bought a Go Cruise throttle positioner for this purpose.  I let it fast idle at about 2K revs for about 30 seconds then I put it in gear and off I go.  The Go Cruise doesn't cause an out of sync issue with the TBs like the choke does since it works on the throttle directly and it is handy when riding to give my right hand a break on a long ride.

[Ralph1212]

James,

 

From the previous owner, I have a throttlemeister on mine.  Last year I was using mine to keep the engine from stalling at stops.

[JamesW]

cool.