Fuel delivery trouble (?)

[mjdoliveira]

Have a bit of a baffling thing (for me, at least) going on. I have 2000 V11 Sport with a PCIII. I'll be riding along and suddenly it appears that just for a second the bike will cut out, then will be fine, will cut out for another second, be fine, etc. The interesting thing is that on the first leg of a trip (e.g. riding to work) I will have no problem, but on the return trip, like clockwise the problem turns up. One morning I took it for a bit of a spirited run along a favorite canyon road (Ortege Highway), had no problems with the ride up the highway, but once again had a problem with the return back.

 

The bike has never left me stranded, but the problem does appear to be slowly getting worse. It's guaranteed to happen on the "return" trip, but sometimes it will happpen every 5 seconds, then sometimes every 30 seconds, under load and under cruising conditions.

 

I thought that maybe it was a fuel injector problem (and may still be), but a couple of tankfulls of gas with some cleaner added did nothing to solve the problem.

 

Any thoughts for a less-than-mechanically gifted rider?

[Guest Nogbad]

Here are a couple of suggestions:

 

Could be electrical. Clean the relays under the seat and make sure they are all plugged back in firmly.

 

Second thing, I have heard of cases where the crank phase sensor becomes intermittent when hot. This will get worse until it packs in, but obviously check the cheap things first.

 

Are the HT leads and plug caps clean and in good condition?

[Guzzirider]

I have had exactly the same problem recently. I took the seat off and poked the relays while the motor was running and it turned out to be the fuel pump relay (the one nearest the back on my bike) that was failing and cutting off the fuel pump whenever I went over a big bump.

 

I replaced the relay and the problem seems to have stopped- am about to go for a test ride to see if its really fixed.

 

Guy

 

Just went out for a brief test ride- so far so good.

Edited September 18, 2005 by Guzzirider

[Guest ratchethack]

I have 2000 V11 Sport with a PCIII.  I'll be riding along and suddenly it appears that just for a second the bike will cut out, then will be fine, will cut out for another second, be fine, etc.  The interesting thing is that on the first leg of a trip (e.g. riding to work) I will have no problem, but on the return trip, like clockwise the problem turns up.  One morning I took it for a bit of a spirited run along a favorite canyon road (Ortege Highway), had no problems with the ride up the highway, but once again had a problem with the return back.

 

It's guaranteed to happen on the "return" trip, but sometimes it will happpen every 5 seconds, then sometimes every 30 seconds, under load and under cruising conditions.

MJD, I've got the same year Sport, also have a PC III, and think I've got the same symptoms. In my case the problem was evident before I installed the PC III, and the PC III improved throttle response so much that I just learned to put up with it. In my case, I consider the bike to be in a fairly high state of tune overall. It only happens a few times in an average ride, and the engine doesn't actually "cut out", it only drops one timing signal on one cylinder at a time, and it only happens at low RPM - always below ~3K. At idle, this single dropped signal can at times set up more dropped signals as the engine stumbles, until a steady RPM is restored with the throttle.

 

I've spent some time thinking about this and have cleaned the aperture of the timing sensor several times with no joy. My current theory goes along with what I think a few others have also speculated about this. It seems that the ECU is sensitive to any irregularity within a series of timing signals from the sensor caused by the small amount of "slop" in the timing chain. My symptoms never manifest themselves when the engine's under load or accelerating (I never load the engine to any significant degree below 4.5K RPM! ) Going uphill, at speed, or against a headwind, everything's fine. These are the conditions under which the timing chain is pulled hard, steady, and straight on the "drive" leg of it's circuit around the sprockets.

 

Just as you described, my symptoms also show up mostly on the downhill leg of any round trip, under low or trailing throttle. These are the conditions under which the timing chain is often relatively loose, where it's subject to variance in angular velocity of the crank due to engine pulses at low RPM. Under these conditions the chain is free to "whip" and jump around enough to cause the cam to occasionally change maybe a degree or so of rotation relative to it's properly steady 1:2 ratio with the crank. Under my current theory, the ECU reads an errant signal from the timing sensor at the cam sprocket, identifies it as being within an "out of phase" range, and ignores it, so it sends no spark on that rotation. When the timing chain heats up with the oil, it seems logical that it could be expanding or "stretching" enough to whip a little more, making the problem worse.

 

While this is annoying , it doesn't present a performance problem, because everything's fine when the engine's in the power band. But I'd sure like to find a way to get better control over the timing chain tensioner to see if this nails it.

 

Until somebody comes up with a better theory, that's mine, and I'm stickin' to it. But if anybody thinks I'm just plain off my rocker-arm shaft on this, by all means, please advise!

 

BTW - Neither my copy of Guzziology, nor my shop manual has any pertinent info on the OEM chain tensioners. I haven't had the timing chest open. I assume the tensioner has a spring and slipper block or "blade". If anyone's had any success adjusting (shimming?) the spring to deal with the problem, please advise!

[Guest Nogbad]

Cliff told me his My15M ECU is clever enough to cope with that sort of thing, and so should the flippin' WM unit be. I know it isn't. My bike has exactly the same neutral throttle stumbling around 3 - 4 K too.

[big J]

I'da thought the answer was fairly obvious; if the problem only occurs on the return leg of a journey, dont come back.

Make home the halfway point of your quest, and the bike will run fine.

Jeez.........

[Guest harley]

Have a bit of a baffling thing (for me, at least) going on.  I have 2000 V11 Sport with a PCIII.  I'll be riding along and suddenly it appears that just for a second the bike will cut out, then will be fine, will cut out for another second, be fine, etc.  The interesting thing is that on the first leg of a trip (e.g. riding to work) I will have no problem, but on the return trip, like clockwise the problem turns up.  One morning I took it for a bit of a spirited run along a favorite canyon road (Ortege Highway), had no problems with the ride up the highway, but once again had a problem with the return back.

 

The bike has never left me stranded, but the problem does appear to be slowly getting worse.  It's guaranteed to happen on the "return" trip, but sometimes it will happpen every 5 seconds, then sometimes every 30 seconds, under load and under cruising conditions.

 

I thought that maybe it was a fuel injector problem (and may still be), but a couple of tankfulls of gas with some cleaner added did nothing to solve the problem.

 

Any thoughts for a less-than-mechanically gifted rider?

60563[/snapback]

I had a similar problem at about 12,000 mi. The engine would cut out below 3000 rpm after the bike was thourghly warmed up but only at a light or trailing throttle. As time went by the problem became worse to the point that my rideing pleasure was being compromised. Because it seemed like a lean miss I set my PC111 two points rich on the low speed adjustment. Low and behold the miss went away. I pulled the plugs and checked the valve adjustment which proved to be good. Next I set the TPS and synchronized the throttle bodies and then returned the PC111 to its original setting. Somehow in the 8000 mi since the TPS had last been set it had gone out of adjustment enough to cause my problem. 1000 mi later the bike runs fine and I am waiting for the next problem to apear. Mike

[mjdoliveira]

I'da thought the answer was fairly obvious; if the problem only occurs on the return leg of a journey, dont come back.

Make home the halfway point of your quest, and the bike will run fine.

Jeez.........

60629[/snapback]

 

Spent 2 days trying to think of a snappy comback to do justice to this, but give up.

[Guest ratchethack]

Hitting the halfway point on every lap at track days must be a drag.

[big J]

Spent 2 days trying to think of a snappy comback to do justice to this, but give up.

60808[/snapback]

 

It's only a matter of time.

 

I actually had a similar problem to you, but since my bike is left hand drive, I had the symptoms on the outward journey.

[belfastguzzi]

Spent 2 days trying to think of a snappy comback to do justice to this, but give up.

60808[/snapback]

 

Heheho

 

"a snappy comeback"

 

 

"...don't come back..."

"...trying to think of a snappy comeback"

 

that was a snappy comeback, very good

[Guest rollingthunder]

Have a bit of a baffling thing (for me, at least) going on.  I have 2000 V11 Sport with a PCIII.  I'll be riding along and suddenly it appears that just for a second the bike will cut out, then will be fine, will cut out for another second, be fine, etc.  The interesting thing is that on the first leg of a trip (e.g. riding to work) I will have no problem, but on the return trip, like clockwise the problem turns up.  One morning I took it for a bit of a spirited run along a favorite canyon road (Ortege Highway), had no problems with the ride up the highway, but once again had a problem with the return back.

 

The bike has never left me stranded, but the problem does appear to be slowly getting worse.  It's guaranteed to happen on the "return" trip, but sometimes it will happpen every 5 seconds, then sometimes every 30 seconds, under load and under cruising conditions.

 

I thought that maybe it was a fuel injector problem (and may still be), but a couple of tankfulls of gas with some cleaner added did nothing to solve the problem.

 

Any thoughts for a less-than-mechanically gifted rider?

60563[/snapback]

 

Same here - on a yr 2000 V11 Sport...

 

Mine misses a beat on a light/trailing throttle between 2500-3500. This is typically when I'm snaking through rush hour traffic which is a bit unnerving. She's never cut out - always just misses the one cylinder every now and then. No popping, just a 'fluff' on the missed cycle. The intervals vary, just like on yours - sometimes every 5 seconds, sometimes maybe once or twice on a one hour run home.

 

I was told a while ago that it might be due to a weak mixture, but she was running rich when checked. She's been tuned (no PCIII) at the garage but if anything the missing is getting worse

 

I suppose I should bite the bullet and take her to the main dealer where I bought her for a Guzzi trained mechanic to take a look at her...

[callison]

A friend of mine out in California has a 97 Sport 1100i that has given him the same problems. He changed to the Agostini chain tensioner and states that 95% of the symptoms are gone. The Agostini chain tensioner is about 1/3 the cost of the OEM part. I've bought one for my incredibly fouled up 97 Sport but haven't yet installed it. I'll let you know if that is a solution when I do, but I'm in no particular hurry.

[txrider]

My 2004 with 7300 miles on it does this on occasion and like others here it's usually within 6 blocks of home, return leg. I call this the "PHHTT" syndrome and it's like the bike is complaining- "Don't put me back in the garage, we're having too much fun, dammit".