Breva 750 Fuel Injection Issues

[lostinthemarket]

I was out on my bike this weekend about an hour away from home when the bike started losing power. Barely noticeable at first but continued getting worse until it barely ran and I limped it back home. The EFI light came on intermittently. Main symptoms are just not revving up except when twisting the throttle quickly and I get a burst of acceleration. I have the cables for Guzzidiag but for some reason Guzzidiag doesn't work on my computer so I'm going to have to borrow something from work. I'll update with info from guzzidiag but does anyone have any ideas? It has the 15RC ecu used in the early V7 classics, I believe.   

[lostinthemarket]

Just checked spark plugs. Both have a nice tan color and a big blue spark.

[guzzisteve]

When was the last time the TPS was reset? Have you looked at the fuel filter lately? How about the air filter, if never changed it could be a mouse nest. The diag should work.

edit-- looks like fuel or air

[Kiwi_Roy]

The way it came on slowly reminded me of tank suck or a plugged fuel filter.

[fotoguzzi]

The way it came on slowly reminded me of tank suck or a plugged fuel filter.

me too, tank suck. can you hear a whoosh when you open it under those conditions? test ride with cap off..

[lostinthemarket]

Yes I stopped to take the cap off to release pressure but it made no difference.

I'm thinking it may be the filter. The bike has a steel v7 tank on it and the tank has a weird white coating that I've never fully trusted.

Here's a pic just because:

[beetle]

Does sound like starvation of something. Fuel or air or both.

[Kiwi_Roy]

I don't know what the fuel return is like on the Breva, if it has a regulator separate from the tank slip the hose off and stick it in a glass bottle, if the filters plugged it will just dribble as it primes, should be a full pipe.

If you can't flow test it take the filter off and shake it up with some fuel inside, see what comes out when you let the fuel run back out the inlet.

BTW the pump will be extra noisy if the filter is plugged, the pressure jumps up from 45 to around 70 and the internal relief pops.

Oh, and don't forget to flow test the tank petcock, the filter on it could be plugged also.


Modern V7 Tank or one from the 70s?
The flow on a injected bike is a lot higher than a carb bike, most of it just circulates.
It looks good

[malik]

Just finished helping a mate work on his Breva - it had running problems when he took it off the road, which turned out to be a long blocked up fuel overflow pipe & nozzle (the forward tube inside the tank), and a suspect fuel pump (didn't look pretty at all). We theorise that as the drain was blocked, water would mix with the fuel, contribute to the rough running & the rust on the pump. The corrosion in the nozzle was drilled out, and compressed air cleared the rest of the tube. A slightly used fuel pump I happened to have on hand was fitted, and it's now working fine. The trip up to the Ragged Fringe will be the final test.

[sign216]

I have the cables for Guzzidiag but for some reason Guzzidiag doesn't work on my computer  ...... It has the 15RC ecu used in the early V7 classics, I believe.

Lost,

I see you're in Conn.  I'm up in Mass, and have the old Vehicle Diagnostic Scan Tool (VDST) from Technoresearch that's appropriate for the 15RC ECU.  If you want to come over and hook it up, let me know. 

Essentially VDST was the commercial software, similar to Guzzidiag, before Guzzidiag came out.

Joe

[lostinthemarket]

Thanks for the offer. I grabbed a different computer from work today and was able to run a scan. No codes! So back to the old fashioned way. .yes all signs are pointing to a fuel issue it seems like. Will investigate further

[guzzisteve]

If you want a free flowing evap tip over valve it is the blue/orange one.

[lostinthemarket]

I found the problem!

I went to replace the fuel filter (it had a metal one) and the soft hose on the inlet had a crack! So I replaced it anyway with a Napa Gold 3032 (around $5) as referenced on another site and shortened up the hose. Bike fired up and runs great. Thanks for the support!

[Chuck in Indiana]

Thanks for the update.. 

[guzzisteve]

Nice when you find the problem, sooner or later it happens.

[Muzz]

I found the problem!

I went to replace the fuel filter (it had a metal one) and the soft hose on the inlet had a crack! So I replaced it anyway with a Napa Gold 3032 (around $5) as referenced on another site and shortened up the hose. Bike fired up and runs great. Thanks for the support!

Stored in my memory banks. Thanks for the update.

[antmanbee]

I found the problem!

I went to replace the fuel filter (it had a metal one) and the soft hose on the inlet had a crack! So I replaced it anyway with a Napa Gold 3032 (around $5) as referenced on another site and shortened up the hose. Bike fired up and runs great. Thanks for the support!

If you used regular fuel hose for a submersible application it will fail fairly quickly. You need to use the right type and it is about $10- 15 a foot. SAE 30R10

Also use hose clamps designed for FI hose.





This is my hose of the wrong type that failed. (not installed by me).

[willard]

Beautiful Breva! Is there a thread detailing all of your modifications?

[malik]

If the search tool here doesn't find it for you in the archives, there's lots on the Moto Guzzi 750 yahoo site.

[sign216]

If the search tool here doesn't find it for you in the archives, there's lots on the Moto Guzzi 750 yahoo site.

That site is:  https://groups.yahoo.com/neo/groups/MG_750/info