Cutting Out at High RPM ...

Hi Folks,

I'm having a little trouble with my Y2K R1100RS. It cuts out and misses at high rpm (7000+) in third, fourth and fifth. gear. It doe3sn' seem to do it in first or second. I kinda get the idea that it's fuel related. I'm imagining it can get to 8000 rpm in first and second because it gets there quickly, but in 3-5 it runs out of fuel because it takes long for the tach to climb. I've replaced the fuel filter, fuel pump, and internal fuel lines. That actually cleared it up for about 500 miles, but now it's back again. I'm starting to wonder if it's the fuel pressure regulator. I don't know anything about FPRs. If it fails, could it not allow adequate pressure to build up, causing high rpm running problems?

Things to consider. It's intermittent. It will happen for a few seconds, then it seems to go away, then it comes back. Also, it will occasionally happen at more modest rpm. it will occasionally miss and sputter when I roll on the throttle at 4000-ish rpm. Last, I think it's gas-related, but once or twice it has happened when I hit a bump. That makes me think electrical, but those occasions have been exceedingly rare.

I'm a little stumped so I'm looking for inputs. I'm interested in anything you have to say.

Thanks,

Hi Folks,

 

I'm having a little trouble with my Y2K R1100RS. It cuts out and misses at high rpm (7000+) in third, fourth and fifth. gear. It doe3sn' seem to do it in first or second. I kinda get the idea that it's fuel related. I'm imagining it can get to 8000 rpm in first and second because it gets there quickly, but in 3-5 it runs out of fuel because it takes long for the tach to climb. I've replaced the fuel filter, fuel pump, and internal fuel lines. That actually cleared it up for about 500 miles, but now it's back again. I'm starting to wonder if it's the fuel pressure regulator. I don't know anything about FPRs. If it fails, could it not allow adequate pressure to build up, causing high rpm running problems?

 

Things to consider. It's intermittent. It will happen for a few seconds, then it seems to go away, then it comes back. Also, it will occasionally happen at more modest rpm. it will occasionally miss and sputter when I roll on the throttle at 4000-ish rpm. Last, I think it's gas-related, but once or twice it has happened when I hit a bump. That makes me think electrical, but those occasions have been exceedingly rare.

 

I'm a little stumped so I'm looking for inputs. I'm interested in anything you have to say.

 

Thanks,

Afternoon Jim

That is the RPM & load range that requires both the highest fuel flow & strongest spark so it c-o-u-l-d be either.

You might do a return fuel line fuel flow test as that will prove out (or prove a problem) with the fueling system from the fuel pump pick-up sock though the pump, through the filter, through the pressure regulator, etc.

Even a small split or hole in the high pressure hoses inside the tank could be enough to cause your problem.

You might also install new spark plugs just to remove that from the spark side possibilities.

When you have the plug wires off of the spark plugs then use a ohmmeter from the metal in one side plug wire to the metal in the other side spark plug wire to check the total secondary side resistance (you want to see somewhere around 18k to 24k as total resistance)

Also, look closely to see if the R/H side spark plug wire is contacting the R/H side TB cam when it rotates.

You might also try riding without the air filter element for a quick test -- I have seem the filter element take in water & swell the media enough to block some air flow at high throttle openings high air flow demand & remain swelled enough to block some air flow even after it dries out.

Thanks DR. That gives me a few things to play with. You 're saying to pull the plug wires and check from one side to the other side (basically) through the coil? Sneaky!

Thanks DR. That gives me a few things to play with. You 're saying to pull the plug wires and check from one side to the other side (basically) through the coil? Sneaky!

Evening Jim

Yes, that checks the entire secondary, won't tell you what part is the problem (if there is one) but if resistance is within reason then it can tell you that the secondary is basically OK.

19.4 K ohms. I'll try the no-air filter trick tomorrow.

Jim,

Do you have a different set of injectors to try to eliminate an injector problem?

I don't, but I'm thinking about giving that a try, or at least trying to clean mine.

It wasn't the air filter. I'm starting to become intrigued by the TPS. Is there a way to check it? Can I use a voltmeter to check the sweep?

It wasn't the air filter. I'm starting to become intrigued by the TPS. Is there a way to check it? Can I use a voltmeter to check the sweep?

Afternoon Jim

Yes, you can check both the low throttle reference (pin 1 to 4) & full throttle reference (pin 3 to 4). You can also check the 5 volt supply from pin 2 to pin 4). Pin 2 to pin 4 should show a steady 5 volts.

Hi again DR,

I checked the voltages. At pins 1-4 it starts at about 0.35 volts and goes to 4.5. It stops increasing after about 1/2 throttle.

At pins 3-4 it starts at 4.53 and decreases to about 0.15 at half throttle, then stays at 0.15 until full throttle.

Does that sound right?

Hi again DR,

 

I checked the voltages. At pins 1-4 it starts at about 0.35 volts and goes to 4.5. It stops increasing after about 1/2 throttle.

 

At pins 3-4 it starts at 4.53 and decreases to about 0.15 at half throttle, then stays at 0.15 until full throttle.

 

Does that sound right?

Evening Jim

As L/H throttle is rotated from closed to open the voltage should scroll smoothly from just under .4v to about 5v between pins (1) & (4) for about the first 1/4 of rotation. The measurement between pins (3) & (4) should scroll smoothly from about 0v to 5v from closed throttle to full open throttle.

Did you measure between pin (3) & pin (4)? It sort of sounds like you measured between pins (3) & pin (2).

Just checked it again. Pins 1-4 works like you say. Pins 3-4 go from 4.5 to 0.15 at about half throttle. (Assuming pins numbered left to right.)

Just checked it again. Pins 1-4 works like you say. Pins 3-4 go from 4.5 to 0.15 at about half throttle. (Assuming pins numbered left to right.)

Evening Jim

pin 4 = brown/gray

pin 3 = white/gray

pin 2 = green/yellow

pin 1 = white/red

Just checked it again. Pins 1-4 works like you say. Pins 3-4 go from 4.5 to 0.15 at about half throttle. (Assuming pins numbered left to right.)

 

Evening Jim

 

pin 4 = brown/gray

 

pin 3 = white/gray

 

pin 2 = green/yellow

 

pin 1 = white/red

Well THAT's a stupid numbering system, LOL. Pin 3-4 goes from essentially 0 to about 3.95. Is that a problem?

Just checked it again. Pins 1-4 works like you say. Pins 3-4 go from 4.5 to 0.15 at about half throttle. (Assuming pins numbered left to right.)

 

Evening Jim

 

pin 4 = brown/gray

 

pin 3 = white/gray

 

pin 2 = green/yellow

 

pin 1 = white/red

Well THAT's a stupid numbering system, LOL. Pin 3-4 goes from essentially 0 to about 3.95. Is that a problem?

Evening Jim

Probably not a problem, does it scroll smoothly with no dips or jumps?

Your pin 1-4 is also slightly low so it could be that your voltmeter puts a little more load on the internal resistors.

Just to be sure, what in the static voltage from pin 2 -- green/yellow to pin 4 -- brown/gray (that should be pretty close to 5v)

3-4 runs up smoothly. 2-4 is steady at 4.91.

At this point I'm tempted to try a used TPS. Does it matter that I'm looking at an 1100? I know the 1150 is supposed to learn the values, but I thought the 1100 series was not adaptive.

3-4 runs up smoothly. 2-4 is steady at 4.91.

 

At this point I'm tempted to try a used TPS. Does it matter that I'm looking at an 1100? I know the 1150 is supposed to learn the values, but I thought the 1100 series was not adaptive.

Evening Jim

TPS is the same between the 1100 & 1150 -- (13631461852 SWITCH)

It wouldn't hurt to try a new TPS, even if it doesn't help you will have a spare in your kit.

1100 is not adaptive but the adaption is in the Motronic not the TPS.

It wasn't the TPS. I'm starting to convince myself that I see the tach jumping around when this is happening. HES? I have a spare so I'm going to toss it in there and see what happens.

It wasn't the TPS. I'm starting to convince myself that I see the tach jumping around when this is happening. HES? I have a spare so I'm going to toss it in there and see what happens.

Afternoon Jim

If you throw enough parts at then you might eventually solve the problem but that isn't a very efficient way to troubleshoot a runability problem, not to mention it can become expensive.

You said the problem wasn't showing up in the lower gears, just keep in mind that an HES problem shouldn't be engine load sensitive or gear position sensitive.

Have you run the fuel return line flow test that was mentioned way back at the beginning of this thread ???????????????????

I know that running a troubleshooting test isn't as exciting as throwing parts at it but you REALLY have to verify fuel flow at some point or another.

Thanks DR. It has started showing up in all gears now (Yay!). I'm going to try the HES. While I'm doing that I'm going to check the resistance at the plug wires and the coil. If I don't see anything interesting there I may break back into the fuel tank and have a look around. I replaced the fuel filter, fuel pump, and u-hose last time. I'll do all the other hoses this time.

Thanks DR. It has started showing up in all gears now (Yay!). I'm going to try the HES. While I'm doing that I'm going to check the resistance at the plug wires and the coil. If I don't see anything interesting there I may break back into the fuel tank and have a look around. I replaced the fuel filter, fuel pump, and u-hose last time. I'll do all the other hoses this time.

Evening Jim

Your 2000 1100 should have the later coil so secondary should be somewhere around 7k +/- ohms at room temperature. Each plug wire should be somewhere around 5.8K (5k-6k range give or take). If by chance your bike has the early coil (doubtful) then you might find the coil secondary around 11k-13k at room temperature.

If your problem came on slowly then after tossing parts at it & testing (qualifying) the fuel return flow then if that (fuel flow) isn't the problem then you might end up eventually having to get the fuel injectors cleaned & flow tested (kind of difficult to test for & define at home).

It never sounded like the TPS was your problem. As DR suggested run the return flow test. You don't have to go into the tank. You don't even have to remove it.

Take the hose off the upper fuel distributor line and clamp it. Then add a hose to that same fuel distributor plastic fitting and point it into a gas can. Start the bike and let it idle for 60 seconds. Shut off the bike and measure the fuel. You're done.

It never sounded like the TPS was your problem. As DR suggested run the return flow test. You don't have to go into the tank. You don't even have to remove it.

 

Take the hose off the upper fuel distributor line and clamp it. Then add a hose to that same fuel distributor plastic fitting and point it into a gas can. Start the bike and let it idle for 60 seconds. Shut off the bike and measure the fuel. You're done.

Thanks again guys. Quick question. Is it volume I need to be worried about, or pressure, or both?

It never sounded like the TPS was your problem. As DR suggested run the return flow test. You don't have to go into the tank. You don't even have to remove it.

 

Take the hose off the upper fuel distributor line and clamp it. Then add a hose to that same fuel distributor plastic fitting and point it into a gas can. Start the bike and let it idle for 60 seconds. Shut off the bike and measure the fuel. You're done.

Thanks again guys. Quick question. Is it volume I need to be worried about, or pressure, or both?

Morning Jim

Both, BUT, if you get flow out of the RETURN line from the rear then that means that you DO have enough pressure to open the pressure regulator valve (40+ psi) so if you have return flow then you are pretty darn sure that you have enough pressure.

Now if you get no return flow (or very little return flow) then you could have either a flow problem, or a pressure problem, or both.

The return flow test is just a quick verification on IF you have enough flow at enough pressure --if it fails the return flow test THEN you have to go looking for the WHY.

OK, that totally makes sense. Thanks.

(Unfortunately I'm also fixing a recalcitrant CBR600 at the same time, so the Beemer has to sit for a day or two.).

Hi guys,

Well, it ain't a problem inside the fuel tank. I did the return flow test today. I didn't put a stopwatch on it, but I got out almost two gallons over course of a few minutes, and it was coming out with a quickness. On to the HES, plug wires, and coil!

The test would have more meaning if you measured the amount in one minute. No stopwatch is needed, just the second hand on a wristwatch. It's hard to tell if you had more or less than 2 liters per minute.

Ha! It was the HES. Or, not the HES itself, but the plug at the end of the pigtail. The HES had been rebuilt as some point in the past. In fact, I had previously swapped it out with the original because I like the idea of a rebuilt HES instead of the 18-year-old one. While troubleshooting this problem I was running out of ideas and decided to swap the original back in. As I unplugged the rebuilt HES one of the wires separated from the plug, right in my hand. Man, I almost wept for joy when I saw that. Turns out the solder just broke where the wire attached to the connector. It was connected enough to get the bike running, but add a little vibration and / or wind and it pulled the connection apart. Sure enough I installed the original HES and the bike is running great.

I think I tricked myself a few times when I was working on the fuel system. I I moved the HES wire around as I took the tank on and off, which changed my symptoms and me think it was fuel-related. The main tell for the HES problem was that the tach would move a little more than I thought was appropriate when the problem occurred. And once, just for an instant I saw the tach increase as the bike sputtered and tried to die. That really didn't make sense so I started to seriously consider the HES.

In any event, thanks for reading and thanks for the help. Time to put some miles on this baby.

....Turns out the solder just broke where the wire attached to the connector...

SO GLAD YOU ARE SORTED. It's a big relief isn't it.

Are you saying the wires were soldered and not crimped at the connector?

If so, was this a professional rebuild. Solder is not your friend.

....Turns out the solder just broke where the wire attached to the connector...

SO GLAD YOU ARE SORTED. It's a big relief isn't it.

Are you saying the wires were soldered and not crimped at the connector?

If so, was this a professional rebuild. Solder is not your friend.

Looks like on that particular wire he missed with the crimp, so it was being held only by the solder.