| |
 | |
|
Originator: Dungyman
|
Level 1 Member
|
Date:
06 July, 2009 - 06:16 AM
|
|
Hi everyone.This will be long.I have a 2003 6125 afm in a commercial fishing boat in Alaska.For the first time ever an alarm on the guage panel came on and the codes were SPN 1569 and FMI 31 which the book says is fuel derate and the other code was SPN 94 and FMI 18 which is fuel supply pressure moderately low.The fuel pressure at idle ( 625 rpm ) had dropped to 39 - 41 psi when 44 or 45 were the norm thus the alarms.Fuel pressure at cruising speed ( 1400 rpm ) had dropped to 61 psi when 68-70 were the norm.I changed fuel filters ( which I do religiously so I doubted that was the problem ) and it didn´t help.Changed fuel pressure sensor and no change.Changed fuel pump and that actually brought the cruising speed ( 1400 rpm ) fuel pressure back up to 66 psi ( not the normal 68-70 but at least 5psi higher than 61 psi ) but the idle pressure remained at 39-41. we disconnected fuel return line and ran engine while holding return line hose end in a bucket under level of fuel to see if air was coming out ( maybe sucking air from filter housing or fittings or such ) but three of us could not see any air come out the hose.We then put a pressure guage on the quick release on the fuel filter housing manifold ( the one you use to bleed air after a filter change ) and ran engine at idle and the pressure was to low.It read 45 psi when the book said it should be between 60-80 psi.We then ran engine at full power ( 2100 rpm ) and it was within the books range which was 70-90?Anyway the full power test was within range but I can´t remember exactly what the pressure read.We then put a vacuum guage on the primary filter housing to see if there was any obstruction and there was not.It stayed at 0 at any rpm.We took the fittings off the fuel filter housing to see if there was any screens but there was not.There is a check valve on the outlet side of the filter but it appeared to work after teasting with a pencil push on it..My theory was that the check valve was not opening all the way and that therefore at idle the pressure would not change but with a new fuel pump and at 1400 rpm´s I might gain the 5 psi that brought it up to 66 psi.My mechanic said it was not the problem as he was the one who pushed on it with pencil and thought it felt fine.It gets better. so I went on a salmon seine trip with boat and leaving town at 1400 rpm I had 66 psi fuel pressure.It was 12 hours to fishing grounds and I fished 5 hours and ran back 12 hours home.Just before home the fuel pressure guage flickered between 56 and 57.The idle ( 625 rpm ) pressure is still 39-41 so I think that shoots down my theory of bad checkvalve because I have lost 10 psi at 1400 rpm but none at idle.Every other component has been changed I think,I´m stumped!! I will be calling John Deere and anyone else I can think of.My salmon season is just starting and I can´t afford down time and certainly not to have engine quit at the most inopportune time with 5 people aboard.Sorry this is so long winded and any suggestions would be appreciated!!! Thanx!!! Bill edit...So after coming home and engine cooled off overnight I started it up and after warm up I ran it at 1400 rpm at the dock and fuel pressure was 64 psi ( up from 56-57 from the night before ). Is this now a temp related problem? Also some dock talk was that possibly an injector problem. Still stumped!!! Thanx for any help. |
| |
|
|
|
Response #1 from: Port Engineers
|
Level 2 Member
|
Date:
25 September, 2009 - 06:34 PM
|
|
(Archived Message - Members Only) |
| |
| Port Engineers | | Mm 102.5,Key Largo,
Florida, 33037,
United States
Tel: 305-451-1864, Fax: 305-451-4772, , Email | |
|
|
Response #2 from: Port Engineers
|
Level 2 Member
|
Date:
06 November, 2009 - 11:29 PM
|
|
(Archived Message - Members Only) |
| |
| Port Engineers | | Mm 102.5,Key Largo,
Florida, 33037,
United States
Tel: 305-451-1864, Fax: 305-451-4772, , Email | |
|
|
