R1100RT Stalls when twisting throttle

[Zulu5Oscar]

Following a 6 month hiatus, I took the RT around the neighborhood and it started to lose power, bogging down when I twisted the throttle. Got the bike home and thought I may have had some stale gas so I drained the tank and filled ¼ full with new fuel. When I try to start the bike, it will start initially and idle for a while however when I twist the throttle, it will bog and stall. If I twist the throttle back and forth rapidly, I can get the RPMs up but that’s it. Thinking it was the fuel filter, I replaced that, same results. I tested the fuel output from the pump and it seem low so I replaced the fuel pump with same results. I am stumped as to what the issue is. Any ideas? Also, what should the velocity of the fuel look like when coming out of the injectors? Mist or stream?

[SKYGZR]

Mist/"Spray". Good spark on both sides? Plugs renewed/checked? Airbox checked for obstructions (critter nesting)? Valve clearance's?

Throttle cables seated correctly in their respective holders? Could be a failed HES. Check spark and plug condition(s).

[dan cata]

Following a 6 month hiatus, I took the RT around the neighborhood and it started to lose power, bogging down when I twisted the throttle. Got the bike home and thought I may have had some stale gas so I drained the tank and filled ¼ full with new fuel. When I try to start the bike, it will start initially and idle for a while however when I twist the throttle, it will bog and stall. If I twist the throttle back and forth rapidly, I can get the RPMs up but that’s it. Thinking it was the fuel filter, I replaced that, same results. I tested the fuel output from the pump and it seem low so I replaced the fuel pump with same results. I am stumped as to what the issue is. Any ideas? Also, what should the velocity of the fuel look like when coming out of the injectors? Mist or stream?

 

Remove the plug on the TPS, that's the black box on the L/H side intake and see if with it disconnected it does the same.

 

You said you have drained the old gas, but are you really sure you got it all out? If water would be in there, it would lay out on the bottom of the tank and would describe your simptoms

 

Dan.

[Zulu5Oscar]

Dan,

 

Yes on the fuel. When I removed the tank to replace the fuel filter I drained the entire tank bone dry. Did it once again when I later replaced the fuel pump. As for unplugging the TPS, it oddly seems to run a bit better when unplugged???

[cruisin]

When I finished installing my driving lights and a few other things on my newest RT, I experienced something similar to what you describe. Upon removing the fairing panels again, I dicovered I had inadvertently gotten one of the power power wires for the driving lights up against the rotating cam of the right throttle body and it was peventing it from opening with the left one. Is it possble something is stoping one of yours from opening proeperly; maybe a broken cable or something else jamming one side?

[Zulu5Oscar]

Does this indicate a bad TPS?

[NonComp]

Does this indicate a bad TPS?

What bike? The 1150's require manual calibration of the TPS following battery discontent or dead (I believe it is key on, not started, rotate throttle from closed to fully open twice, slowly, then key off). The 1100's TPS will not change unless the screws are loosened on the left-hand TB.

 

 

[dan cata]

Does this indicate a bad TPS?

 

If you have a bad TPS, you can disconnect it and see how the engine is running. IF it runs the same, you may have found the problem

 

Dan.

[Zulu5Oscar]

Thanks everyone, I suspect that the TPS may be the culprit. I will order today and let you all know if it does the trick.

[NonComp]

Thanks everyone, I suspect that the TPS may be the culprit. I will order today and let you all know if it does the trick.

Sorry, I missed the R1100RT in your topic title. So, have you checked the TPS voltage and tried setting it?

[Hedgry]

Any chance critters built a nest in your air filter while it was sitting for 6 months? I had a Rebel 450 some time ago that did the same thing after sitting over winter, ended up being an air filter full of leaves and nuts

[dirtrider]

Thanks everyone, I suspect that the TPS may be the culprit. I will order today and let you all know if it does the trick.

 

Afternoon Zulu5Oscar

 

Sometimes low fuel pressure or low fuel supply to/through the injectors will allow a slight static engine running improvement with the TPS disconnected as the TPS is the major open loop fueling controller on throttle change so disconnecting it might mean the less fuel is requested upon opening the throttle.

 

You might not want to buy an expensive TPS before at least doing some testing on your old TPS.

 

The TPS is a very reliable sensor with very few actual real world failures. About the only thing that kills a Bosch TPS is extreme long use wear, having the bike fall over on them, or somehow manually damaging them. The internal resistances are so high that even sending overcurrent to a TPS seldom results in internal damage.

 

Just disconnecting the TPS and engine running better is not in any way a valid test as the TPS is a major input sensor so the engine really won’t operate anywhere near drivable without it in place and working.

 

If you look closely at the side of the TPS where the wires plug in you should see numbers 1 through 4.

 

-If you have a small voltmeter/ohmeter start by measuring the voltage coming in on the wire harness side of pin #(2). Measure between pin (2) and pin (4)—You need to see 5 volts.

If you show 5 volts then the supply voltage from the Motronic is OK and the return (ground) back to the Motronic is functional.

If you don’t have 5 volts (pin 2 to pin 4) then find out why as the TPS won’t operate without it. (maybe a mouse chewed the wire harness up, etc)

 

Next, (on the TPS itself)- set your ohmmeter to K ohm scale and measure the resistance between pins 1 & 2—should be around 2 K ohms +or- a little. You are looking for way out of specs here.

 

Next set your ohmmeter to ohms scale and measure between pins 2 & 3—Should be between about 600 ohms and 1400 ohms (again give or take a little) again you are looking for way out of reason here.

 

Next, if you pass all the above tests then your TPS is probably healthy but if you want to test farther plug the TPS wire connector back in then with key on try to rig some small voltmeter probes (or real small wires placed in the 1 & 4 connector wire pins before re-connecting the connector to the TPS) so you can monitor the voltage swing between pins 1 & 4 as you operate the throttle.

SO- With your voltmeter set to something like the 10-12 or 15 DC volt scale (what ever your meter has that’s close) and connected to the plugged-in TPS connector the voltage between pin 1 and pin 4 should be under .399 volts at closed throttle (choke off), but be above .300 volts closed throttle (choke off). Now slowly move the throttle to about ½ throttle, between pins 1 & pin 4 you need to see the voltage smoothly increase from whatever it was in the .3-.399 range to about 5 volts.

 

You can do about the same voltage test between pins 3 and 4 and that should smoothly scroll from it’s lowest voltage at part throttle to about 5 volts at wide open throttle.

 

If your TPS meets the above your engine runability problem probably lies elsewhere.

 

Maybe look for signs of mice eating the wires somewhere or a problem with fuel pressure/supply, or a plugged air intake from mouse nest, or plugged screens in the tops of the fuel injectors, or low voltage to the injectors, or maybe a corroded fuse lowering system voltage somewhere, etc.

 

 

[kmac]

Clogged injector from bad old fuel would be my first guess. The symptoms sound exactly liked a clogged jet in a carburetor. FI doesnt have jets but it does have injector nozzles which when clogged act like clogged jets. There are places that can clean resonably...i forget the companies name right now....my brain is jacked today

[sardineone]

I had a bike that ran perfectly before sitting in a shop on consignment for a few months. I ran through all the usual suspects. I had no stabilizer in the fuel and I think that was the start of the problem. In the end, the bad fuel had fouled the spark plugs. The plugs didn't look bad but, changing them made all the difference. I thought fouled plugs was a 2 cycle engine thing. I learned this lesson after pulling the carbs off twice for cleaning.

[DFWBo]

Mine 1150 did this, turned out to be the stick coils

[Ian]

Following a 6 month hiatus, I took the RT around the neighborhood and it started to lose power, bogging down when I twisted the throttle. Got the bike home and thought I may have had some stale gas so I drained the tank and filled ¼ full with new fuel. When I try to start the bike, it will start initially and idle for a while however when I twist the throttle, it will bog and stall. If I twist the throttle back and forth rapidly, I can get the RPMs up but that’s it. Thinking it was the fuel filter, I replaced that, same results. I tested the fuel output from the pump and it seem low so I replaced the fuel pump with same results. I am stumped as to what the issue is. Any ideas? Also, what should the velocity of the fuel look like when coming out of the injectors? Mist or stream?

 

On my R1100RT here is what caused the same symptoms after my bike was laid up for a while.

 

In case you have not guessed. The damage was caused by a mouse.

 

regards,

 

Ian

[Zulu5Oscar]

Thanks all for the feedback. D.R., all tests that you indicated check-out on the TPS, I'm glad you posted the testing proceedures, just in time to stop the order for a new TPS.

I guess I will start with plugs and work towards injectors. The bike has allways been garaged and pampered, no way any rat would get close to it : )

[Ian]

Thanks all for the feedback. D.R., all tests that you indicated check-out on the TPS, I'm glad you posted the testing proceedures, just in time to stop the order for a new TPS.

I guess I will start with plugs and work towards injectors. The bike has allways been garaged and pampered, no way any rat would get close to it : )

 

Mine was garaged and pampered too but I forgot to plug the air intake. In addition on a different occasion one mouse eat through my bike's alarm cables which resulted in the bike refusing to start.

 

I'm referring to a field mouse not a rat!

 

regards,

 

Ian

[sardineone]

BTW when you get ready to pull the plug caps(coils), it's a very good idea to disconnect the small wires to the cap prior to removal. They are on the fragile side.

[AndyS]

The

BTW when you get ready to pull the plug caps(coils), it's a very good idea to disconnect the small wires to the cap prior to removal. They are on the fragile side.

 

The 1100 doesn't have these. The stick coils were from twin spark 1150 onwards.

 

Andy

[kmac]

I dont care if the bike is in your bedroom, in bed next to you, it could still be a mouse or a rat...not saying it IS, just that it could be.

[kamlooper]

Have to agree, had my bike in the heated garage,air tight I thought, after 2 months mouse had built nest in air box had babys,unknown to me I started bike road it a bit then noticed smell of rotton animal.

I dont care if the bike is in your bedroom, in bed next to you, it could still be a mouse or a rat...not saying it IS, just that it could be.

[dan cata]

Have to agree, had my bike in the heated garage,air tight I thought, after 2 months mouse had built nest in air box had babys,unknown to me I started bike road it a bit then noticed smell of rotton animal.

I dont care if the bike is in your bedroom, in bed next to you, it could still be a mouse or a rat...not saying it IS, just that it could be.

 

Don't forget to post some pics )

[kmac]

It is not getting it into the bed, it is getting it up the stairs.. lol

[NonComp]

What's this about getting it into bed. My wife says I'd be just as happy throwing a tarp over the bike and sleeping on the ground beside it. That's because it won't fit in the tent when its raining...

[kmac]

I have slept on the ground out of doors right next to my Bike before....I love cowboying it. Just a bed roll strapped on the back and off i go for a couple of days. Sleep right on the ground.

[Zulu5Oscar]

OK, just a quick update. I replaced the spark plugs, same symptoms. I was still baffled as to why the Sx would be the same with or without the TPS plugged in so I replaced the TPS with a known good one (Thanks Jeff) still no joy. I guess my next step is to replace or repair the injectors. One of you made mention of having them sent out to be “cleaned”? Has anyone done this before with good results? If so, what company? I’m hesitant to send out injectors to a place that sells them only to be told they can’t be fixed and be stuck with a cleaning bill AND have to buy new ones (does that sound pessimistic ?)