Flooding

[Guest ratchethack]

It isn't the injector! Tonight I swaped the injectors right for left. The problem stayed on the right side. What would cause this? I guess the next step is to remove the power commander to see if it is the cause of the problem.

 

 

Mainly I have this problem when I start the engine. After a brief warm up it goes away. It does it more often when the engine is warm. It may be worse in the afternoon when the air is hot.

Good move, eliminating the injectors. There ain't much left to check now.

 

I just went back to your opening post. You checked for spark, but that was at idle, and the prob is intermittent on the road.

. . .running on just one cylinder. When it does this it is obvious it is getting a huge amount of fuel to the right cylinder.

I assume you've also tested & eliminated the coils? If not, you want to eliminate this, might try switching them same as you did the injectors to see if the fault follows the switch. Coils can be notoriously heat sensitive when they fail.

 

The PC is very unlikely to have an intermittent fault on one FI circuit and not the other. But seems to me you've got this thing narrowed down far enough where it couldn't hurt to try disconnecting it just to be certain and narrow the possibilities down a bit further.

 

Assuming you can eliminate the PC as a fault source, you're left with an intermittent FI signal fault that could only be coming from the ECU, or connectors and wires between ECU and the injectors. I'd carefully test these for continuity pin by pin, whilst moving the wires and connectors to simulate heat/vibration conditions on the road.

 

Good luck.

[Dan M]

Try to isolate the trouble. You are on the right track. Now, is it flooding or merely not lighting the fuel. The injectors are powered up when the key is on and the ECU pulses ground to them. It is possible that there are individual drivers and I'd have to see a diagram but I'm thinking there is only one driver in the ecu for both injectors and they gang fire. If a driver fails it usually goes open and you get no fuel. A short to ground would most likely be permanent and the inj would just pour constantly. There is a possibility of the signal (ground) wire for that injector shorting to ground at times causing one cylinder to flood but it seems unlikely.

As Ratchet noted, it is unlikely that the PC is causing only one side to act up. By the same token I believe it is unlikely for the ECU to do it, especially intermittently. Possible on both counts but unlikely. Take the PC out of the picture just to see.

In an earlier thread it was discussed that the ecu dumps rich for the first 3000 revolutions after start up hot or cold. (Just under 3 minutes at idle.) This could present more of a problem on a hot engine as the extra fuel is not necessary and may cause it to flood if the mix was too rich to begin with.

A couple of cheap simple tools may help you to narrow it down. A tool truck or well stocked auto parts store should have an injector test lamp AKA noid light. This plugs in place of the injector and you can see the pulses. Then you can compare side to side. Not as good as a lab scope but you get the idea. Also a spark tester that plugs in-line between the spark plug and wire will indicate if you are losing spark from the coil.

 

Is your problem primarily at idle? Can it be as simple as idle mix is way rich and fouls plugs at idle? Can there be a large vacuum leak on that cylinder causing the misfire and resulting unburned fuel to pass at idle? - just throwing stuff out there to be considered.

[tricatcent]

Tonight I am going to try cleaning all the connectors to do wtih the PC and ECU with contact cleaner. I did ride this bike a lot when there was salt on the road.

 

The problem can occur at start up, but sometimes it happens when you are cruising too. I am sure the injector is stuck open because the amount of fuel that comes out the joints of the pipes is huge. It looks like the same amount of flow as I saw when I cleaned the injectors.

 

That is one of the reasons I don't think the problem is with the spark.

 

Nigel

[Dan M]

Tonight I am going to try cleaning all the connectors to do wtih the PC and ECU with contact cleaner. I did ride this bike a lot when there was salt on the road.

 

Nigel

 

Remember, you need good connections to open the injector. Poor, corroded connections will result in an injector that does not open. If you think it is open when it shouldn't be look for the trigger wire to be rubbed through and touching a ground (or do you say earth in BC? ) source somewhere.

[tricatcent]

Yes I realize that a poor connection would probably not result in the trouble I am having. It may be there is a short though, of an intermittent kind. Or perhaps a bad connection to something like a temp sensor. Who knows.

 

In BC we say ground, but I am English, and have owned many British cars and motorcycles so I understand earth as well. It seems as though there are a lot of Triumph and Norton owners in this forum.

[Dan M]

It seems as though there are a lot of Triumph and Norton owners in this forum.

 

 

Yes, seems many of us are masochists.

[raz]

It isn't the injector! Tonight I swaped the injectors right for left. The problem stayed on the right side.

 

I told you to do that one month and three weeks ago, nag nag

 

I have a feeling this was good news. Estimated cost for repair went down by 98%, that is my bet anyway.

[Guest ratchethack]

I'm changing my read to a 95% probability of an ignition coil headed South.

 

Again, best do an oil change to get all that fuel out of the crankcase oil.

[savagehenry]

Yes, seems many of us are masochists.

I keep saying I'll buy a UJM, but can NEVER actually bring myself to do it...

[Dan M]

I keep saying I'll buy a UJM, but can NEVER actually bring myself to do it...

 

Yep, had several over the years but I seem to have moved on to bikes with "character" (don't know if that is good or bad)

BTW, good new avatar SH.

[tricatcent]

Tonight I disconnected the Power Commander. Now the bike is fixed!

 

The part that was faulty was not even a Moto Guzzi part.

 

I think there must be a pinched wire in the harness for the PC.

 

The thing that surprises me most though is how well the bike runs. I think it runs better than it ever did. I knew the map I had was not that good. My bike has Mistral oval carbon cans and a Stuchi cross over, as well as K&N pods.

 

You would think it might run lean, but I have an air fuel ratio gauge and it indicates between 12.9 to 14 air fuel ratio. Usually it is 13.3. The only time it runs way to lean is just for an instant when the throttle is wacked open suddenly.

 

I don't think I will put the PC back on.

 

Nigel

[savagehenry]

BTW, good new avatar SH.

Thanks, taken at the Mindoro Cut, a little north of Lacrosse. Avoided all "slab" in favor of back roads, 772 miles of great riding in 24 3/4 hours. Hit the MG Elkader Rally (10:00 pm and the streets were empty. I envisioned there would be crazed bands of MG marauders laying the villages to waste. Apparently thats those "other" V twin guys...), did Pikes Peak observation deck for the sunrise. Man, I love these bikes!

[Tom M]

I think there must be a pinched wire in the harness for the PC.

 

Hi Nigel,

Does the connector on your ECU face up towards the seat base or down toward the rear wheel? If it faces up damage to the harness could be from the seat base flexing and contacting the ECU connector on the harness.

 

I recently had an intermittent electrical fault that appeared to be the PCIII harness. More troubleshooting proved that the ECU itself was damaged, apparently from lack of sufficient clearance between the seat base and the upward facing ECU connector. I don't know if the ECU was installed at the factory or by the previous owner with the connector facing up, but if yours is facing up consider flipping it over or you might have more problems in the future.

[tricatcent]

My ECU has the plug facing down. There isn't much clearance there really.

 

After removing the power commander I have put about 700 kms on the bike trouble free. The gas milage is now running about 5.5 liters per 100 km instead of 6.5 or 7 as before. It is running at a good air fuel ratio, usually in the low to mid 13s. The only time it runs lean is at about 3000 RPM with the throttle almost closed. It goes over 15 to 1 air fuel ratio and coughs back through the throttle bodies. It is irritating but you get used to it. I just gear down so the engine is going 4000 then it doesn't do it.

 

Thanks for all your help with this problem guys.

[tricatcent]

My friend who is a guzzi mechanic told me that the coughing is cause by imabalanced throttle bodies. He also told me that a power commander is generally not required on a road bike with only a pipe and crossover like mine. Mine is a lot better without it thats for sure.

 

I decided to balance the throttle bodies by ear, reasoning that I couldn't make it worse because I could always turn it back to the initial position. I fiddled with it a bit on a ride tonight and now I have it perfect. No more coughing. It is really nice now.

 

Nigel