guzziriders.org - moto guzzi forum Homepage
Forum Home Forum Home > Modifications and Restorations > Modifications
  New Posts New Posts RSS Feed - Fuel Injection woes.
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Fuel Injection woes.

 Post Reply Post Reply Page  <12
Author
Message
INSTG8R View Drop Down
Falcone
Falcone
Avatar

Joined: 31 May 2017
Location: Geraldton
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote INSTG8R Quote  Post ReplyReply Direct Link To This Post Posted: 29 Jun 2021 at 12:20
Cheers Brian,
I think you're onto something. This weekend will be fuel pressure test time me thinks. 
I did have to make my own fuel lines up, following the Guzzi fuel flow diagram as the Suzuki outlet and return spouts were different to the Guzzi tank. I also had to re-position the Guzzi fuel filter as things were hitting the tank and frame. Even Mario was scratching his head as to why it was rich instead of lean. It will be the one thing we didn't think of or test. I often remind myself of the true meaning of the word "assume", ass-u-me. hahahaha.
INSTG8R
Back to Top
INSTG8R View Drop Down
Falcone
Falcone
Avatar

Joined: 31 May 2017
Location: Geraldton
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote INSTG8R Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jul 2021 at 14:45
Ok, prognosis: too much fuel Pressure. It appears the pressure relief valve is not doing its job. Fuel pressure to the injectors is meant to be 3 bar +/- .02(42-47psi). I have over 5 bar 110-115psi. Are the pressure valves repairable or replacement only? As I believe the original part have not been available for many years.
INSTG8R
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 15612
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jul 2021 at 16:00
Can't give you a straight answer to that. But I do know that adjustable regulators are available.

Are you sure the pressure leak off pipe is clear back into the tank? You said you had to alter all the pipework as the tank you now have is different.
So many times we have seen that a recent modification is in fact the cause of a problem which occurs just after.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
Gianni View Drop Down
Senior Member
Senior Member
Avatar

Joined: 16 May 2014
Location: Muswell Hill
Status: Offline
Points: 505
Post Options Post Options   Thanks (0) Thanks(0)   Quote Gianni Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 00:21
Check the pressure return pipe into the tank - it was kinked on my Quota and might have been responsible for some issues I had (other components were also suspect so not definitive).

Adjustable solution available from S-D at a price https://www.stein-dinse.biz/product_info.php?products_id=439056#prettyPhoto
Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 15612
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 11:15
Think about it, if that pipe is kinked and so flow drastically restricted then excess fuel cannot return to the tank, so you will get too much pressure at the injectors.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
INSTG8R View Drop Down
Falcone
Falcone
Avatar

Joined: 31 May 2017
Location: Geraldton
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote INSTG8R Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 11:26
Thanks lads but I had the tank off, no pipe kinks and all fuel lines are new with no blockages. I checked pressure between pump and filter, filter and relief valve, relief valve and injectors as well as relief valve and tank return. The tank return side didn’t register any pressure but fuel was flowing slowly. The pressure before the relief valve was 140psi after the valve the 110-115psi. All fingers point to the relief valve. At the meeting moment.
INSTG8R
Back to Top
guzzwiz View Drop Down
Falcone
Falcone


Joined: 05 Oct 2019
Location: Germany
Status: Offline
Points: 35
Post Options Post Options   Thanks (0) Thanks(0)   Quote guzzwiz Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 13:42
Question: Why Moto Guzzi has spent 2 independant air temp sensors, and placed them at different positions? Because they had overstock?
Answer: No, because they are necessary in such arrangement. Imho, it is also nonsens to mount them side-by-side.
I don't expect issues with the fuel pressure. I recommend to discard the pod filders, and put back the old filter box, together with the ATS in its original position.
Next tip: get the free "GuzziDiag diagnostic PC programme, the appropriate OBDII-USB adapter and the Alfa/FIAT-AMP Superseal cable. This is the necessary toolset to work on a Guzzi with EFI. Forget your knowledge about carburettors on such bikes.
Important: the "air screws" are for idle rpm control and vacuum pressure synchronization only, don't try to ennrich or lean gas mixture with them.

Cheers  Hans

presently 850T3/1000cc, V50PA
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 15612
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 14:38
Originally posted by INSTG8R INSTG8R wrote:

Thanks lads but I had the tank off, no pipe kinks and all fuel lines are new with no blockages. I checked pressure between pump and filter, filter and relief valve, relief valve and injectors as well as relief valve and tank return. The tank return side didn’t register any pressure but fuel was flowing slowly. The pressure before the relief valve was 140psi after the valve the 110-115psi. All fingers point to the relief valve. At the meeting moment.

Agreed, it does seem the regulator isn't doing it's job properly.

110psi is around 7 Bar, which would give a very rich mixture.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
Gianni View Drop Down
Senior Member
Senior Member
Avatar

Joined: 16 May 2014
Location: Muswell Hill
Status: Offline
Points: 505
Post Options Post Options   Thanks (0) Thanks(0)   Quote Gianni Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 16:40
I had a conversation with a Guzzi racing engineer recently during which he said they used to modify the standard part in order to raise the point at which the pressure was relieved in order to increase fuel delivery. The modification involved opening the valve.

So it might be possible to open it up and see what is causing the issue. In my case the internal rubber diaphragm failed so the pressure was relieved out of the drain spigot into the hot exhaust pipes Ouch
Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 15612
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 17:15
Increasing fuel pressure is a known tuning aid, but it has to be done with great control.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
INSTG8R View Drop Down
Falcone
Falcone
Avatar

Joined: 31 May 2017
Location: Geraldton
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote INSTG8R Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jul 2021 at 04:04
SUCCESS!!!! As I have changes the tank, repositioned the fuel filter on the frame, the fuel flow from the tank -> pump -> filter -> pressure relief valve -> back to tank must have confused the poor old mechanic working for Mario. on a previous visit he said I had the pressure relief valve back to front so he turned it around for me. (thanks) However after connecting a pressure gauge it worked out I had it correct in the first place. Switched it round, Runs like a dream!! Went for a lovely ride through the local farming district, green wheat fields, yellow canola fields and glorious sunshine. I'm back in love with my old tractor Big smile. Thanks to all for you input and suggestions. Once agin a cracking community!
INSTG8R
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 15612
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 19 Jul 2021 at 08:12
Well at least you know the pump is giving good pressure.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
 Post Reply Post Reply Page  <12
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.078 seconds.