INJECTORS

[Kiwi_Roy]

My V11 has developed a sneeze at low revs, I don't think this is ECU related because it also does the same with a different unit.

It will idle quite nicely then occasionally seems to kick back and stall.

It does the same under way at higher revs and low throttle setting but of course doesn't stall.

I did a check to make sure I wasn't loosing voltage at the ECU, no problem there.

 

I was wondering if it's possibly an injector sticking.

The bike has done 71,000 km, as far as I know the injectors are original. How long will they last?

 

Thanks

Roy

[gstallons]

Do you have access to a non-contact heat gun? If you do, you can check both exhaust pipes for the same temperatures.This will show if one side is rich or lean.

Did this condition happen over time or immediately? Fuel injectors can and will do anything. Your symptom(s) might be attributed to this, I do not know.

You should contact www.lindertech.com in Indiana 1-888-809-3835. These people will take your injectors, flow rate & check spray pattern. They will quote a price to recondition or give you a matched set.

[Kiwi_Roy]

Yes I do have a non contact thermometer. You're right the left cylinder is consistently 5-10 C cooler, right can be in the 120-130 C range.

The thermometer doesn't work so well on the exhaust, I presume the emmistivity is lower but I will try it again this evening.

So you don't think 70,000 kM is high?

They're not that expensive that I wouldn't just buy a new pair if I can figure out what part No

I will checked out your link - they don't seem to sell injectors, at least I couldn't figure it out

In the meantime I will swap them side to side, see what effect that has on cylinder temp.

Thanks

Roy

[docc]

You don't think maybe a fresh valve adjustment, and exacting throttle body balance with careful air bypass screw adjustment might affect those temperature readings?

 

Beyond that, the autos I own need period "fuel system treatment." Techtron, and SeaFoam, make great ones and worth trying before launching your injectors off for "intervention."

 

If your 70,000 kM are high, my 116,000 are scarin' me!

[emry]

Typically when an injector begins to fail they start to leak. This shows up intially as a very rich cylinder. In some rare cases the windings can short or open, one will ruin an ECU and the cylinder is dead, the other will just drop the cylinder.

 

Although getting a set of balanced and flowed injectors is worth the money.

 

KiwiRoy - You seem resourcefull enough, why not make your own flow tester. 555 timer circuit with a controlling transistor works dandy. I'll post a video of the one I made later tonight

 

Your "sneeze" whould be a classic characterisic of a lean mixture.

 

When I began tuning with MyECU my Guzzi required much more fuel than I or others thought necessary. It wouldn't even run on the map that was orginally provided. When running with the OEM unit it had developed a low throttle sneeze and would stall at stop lights. What or why things had changed from new was never resolved. The exhaust CO was 0% when checked.

[Tom M]

Your "sneeze" whould be a classic characterisic of a lean mixture.

 

Yup. I seem to remember that you had your TPS adjusted lean (under 525mV at idle) a while back. That will definitely cause a lean sneeze. A loose header or leaky intake boots will too.

[Dan M]

 

I was wondering if it's possibly an injector sticking.

The bike has done 71,000 km, as far as I know the injectors are original. How long will they last?

 

Thanks

Roy

 

The vast majority of injector malfunction is sticking, dribbling or a poor spray pattern caused by deposits. A good cleaner as docc mentioned will usually fix that.

Mechanically, the spring that closes the pintle can break but it's very rare and fuel would just flow at all times when the pump was running. Electrically, the coil can short or go open. Usually they will short and can take out the driver in the computer. There have been some injectors prone to shorting but I don't think I've ever heard of the units Guzzi uses failing in this way. Either way, they wouldn't work at all so that cylinder would be dead. You can check resistance and compare side to side but I'd bet they are fine.

 

If you suspect an injector, clean it. Past that, look elsewhere as others have suggested.

[Kiwi_Roy]

Thanks Guys,

That's given me something to think about.

 

Dan M, But how to tell if it's sticking? I will try some cleaner as you & Docc suggest

Tom M, I have a MyECU and my sensor is set ~560 mV now

Emry, I would make a tester as you suggest but then I would only use it once, I will try doing a test while cranking over. I will pull the injectors and see if they leak for a start. If I can find a couple of glass bottles I should be able to do a flow test while cranking over perhaps get an idea of the flow pattern.

Docc, I will clean and see if it makes a difference, I did the valves a couple of weeks back and the throttle body ballance within the last couple of months.

 

General comment

It's quiet around here with Raz on holiday

 

Cheers

Roy

[vtv11lemans]

Roy: I agree with Tom M's statement of checking your intake boots (cracks/leakage). I had a similar problem with my '02 LeMans. Started at about 40-45k miles. I had a surging/stumbling problem at 2300-2900 RPMs. Usually at slightly off throttle or steady throttle. No problem below or above that RPM, so I let it go and lived with it. At 60k miles my left intake boot finally cracked through on a ride and the problem grew worse tenfold. The bike started bucking,surging and backfiring across a wider RPM range. Same symptons but far worse. I replaced both boots (left and right) for about $33 US dollars. Easy to swap out as well. Not only did the violence subside but the subtle stumbling I experienced previously totally disappeared and the bike runs incredibly well with improved fuel economy. So if one of your intakes does show cracking (particularly left side- I have a theory on why that is!) then you might want to do a quick and dirty test, seal then up with either electrical tape or some kind of sealent wherever you see significant cracks and see if it runs better. Then order yourself a coupla boots. Got mine through MG cycle in US (888-464-2925).

 

Good Luck. Leon

[Dan M]

Thanks Guys,

That's given me something to think about.

 

Dan M, But how to tell if it's sticking? I will try some cleaner as you & Docc suggest

 

Cheers

Roy

 

 

If it is stuck it does not work at all so that cylinder would be dead. If it has deposits holding it from sealing it will dribble or leak fuel and generally run rich. If the spray pattern is poor it usually causes a misfire under load, more so at low RPM.

Some Seafoam in the gas can not hurt but as others have said, it is probably something else. You can always swap injecters left and right and see if the trouble moves with it.

From your description "sneeze", I'm thinking you get a buck or pop when you twist the throttle from low RPM. If that is the case, I agree with Emry. It is lean.

[Kiwi_Roy]

OK I pulled the boots off but the only cracking was a slight surface crazing. nothing that looked even close to going through, perhaps the PO changed them out at some time.

While I had them off I was able to check the injectors, no sign of dribbling and when cranked shot out a fine mist.

However when I put it all back together and hooked up my balance meter it was about 1 psi out at idle and it seemed to run better, perhaps one of the clamps was a little loose and sucking air.

I will balance it properly tomorrow when I have more time.

Will keep you posted.

 

Roy

[raz]

I too agree it's probably too lean. Other than that, I have found using Raceco specs (0.20/0.25 mm) for valve lash will help idling and prevent low rev sneezes a lot too. My bike runs like an electric train and idle is rock steady. I can almost do without the fast idle lever when cold. BTW the fuel map I sent you has a much too lean idle cell, I've richened it a LOT since. The rest of my map is unchanged. My sensor gave up so I'm running open loop.

[Kiwi_Roy]

I too agree it's probably too lean. Other than that, I have found using Raceco specs (0.20/0.25 mm) for valve lash will help idling and prevent low rev sneezes a lot too. My bike runs like an electric train and idle is rock steady. I can almost do without the fast idle lever when cold. BTW the fuel map I sent you has a much too lean idle cell, I've richened it a LOT since. The rest of my map is unchanged. My sensor gave up so I'm running open loop.

Thanks Raz, I will try the cell a bit richer

How was the holiday in France?

[raz]

How was the holiday in France?

Awesome! I was worried about not speaking the language but that wasn't a problem. Every single person we met was nice and polite, and pragmatic. Camping sites were nice. Roads were truly wonderful, except when trying to pass Paris via the highway ring. I think something was lost in translation, we just got completely stuck for hours trying to find the right way out. Other than that we mostly avoided highways and I think that is a good advice in general. Toll roads and motorcycles just don't match.

[Danr]

My V11 has developed a sneeze at low revs, I don't think this is ECU related because it also does the same with a different unit.

It will idle quite nicely then occasionally seems to kick back and stall.

It does the same under way at higher revs and low throttle setting but of course doesn't stall.

I did a check to make sure I wasn't loosing voltage at the ECU, no problem there.

 

I was wondering if it's possibly an injector sticking.

The bike has done 71,000 km, as far as I know the injectors are original. How long will they last?

 

Thanks

Roy

 

 

Don't know if this is available in Canuck land or a product similar, but might be worth a try to run a heavy dose in your fuel.

 

http://www.chevron.com/products/prodserv/additives/