FG649 Issue

[Turtle59]

G'day blokes and blokettes.

I have a problem. Tricky to describe really, but here goes. Please tell me what you think... I'm a big boy.... I can take it.

We went away on holiday 2 weeks ago towing a 1.5 ton camper behind the canter. The back full of assorted crap, you know the drill. 4 bicycles, 4 kayaks, standup paddleboards etc about another 1/2 ton of stuff.

All started out really well for the first hour of steaming up the highway at 100-110kph. then out of know where the engine started to die then felt like a cylinder cut out. Slowly the engine was running out of steam until finally down to 2nd gear foot flat to the floor it started to pick up again. Back up to 110kph running fine and then a repeat of power loss cutting in and out of cylinders etc. Hills are a lot of fun... down to first gear crawling at about 10kph and the engine actually cut out twice. Then for no apparent reason it would start to run fine again. **** knows. Electrical?????? Fuel??????

I haven't been able to solve the issue as yet.

My first plan of attack tomorrow is to change the fuel filter and see if that is an issue.

Any suggestions gratefully received.

 

[Bris31]

..... My first plan of attack tomorrow is to change the fuel filter and see if that is an issue.

.

That's what I would check along this line first - fuel or air flow - dirty filters or some electrical issue with pump, as it looks somehow engine is starving of fuel or air. But there are many experts on this forum who can give better idea.

But ii is amazing to see it is driving up to 110kph with towing. How much rev you get at that speed? My truck is 3000 RPM at 95kph and I don't like that engine noise - beside the fuel consumption.

 

[PKDreamers]

We had a similar problem with our FG649 .
I found the problem was with the hand primer pump,it was leaking at idle and was sucking air while running .
Replaced hand pump and all good now.

 

[steve4wdaus]

Good find guys, safe tripping
Steve

 

[pugslyyy]

Another vote for a fuel restriction. Sounds to me like the fuel supply is not able to keep up with the engine during heavy load.

If you have an OBD2 reader there will be a low fuel pressure code stored if this is the case (this code does not throw a check engine light, though)

 

[canter tourer]

On my 639 I get something similar where it loses power and slows right down, first time I thought the motor had blown. I've eventually worked out that somehow and forgive me for the poor explanation, but there is a build up of vacuum in the fuel tank and it seems the fuel pump cannot draw enough fuel against this pressure build up, but it is instantly relieved by cracking the fuel tank fill cap, with an audible rush of air into the tank and the problem resolves completely until at some other random point down the road it might happen again and simply repeat the process. I figured the tank needs some sort of external breather but that hasn't happened yet.
Dave

 

[selfy]

check the breather on top of the fuel tank

 

[kerry]

I doubt this is the problem, but I've always wondered about the non-mechanical connection between the accelerator pedal and the IP on my truck (99FG). I've wondered what are the symptoms of a failure in that system.

 

[pugslyyy]

I doubt this is the problem, but I've always wondered about the non-mechanical connection between the accelerator pedal and the IP on my truck (99FG). I've wondered what are the symptoms of a failure in that system.

On mine it is a hard fault that illuminates the check engine light and deactivates the throttle. Even if the issue is corrected you have to turn off the ignition, wait, and then turn it back on again to regain pedal control.

 

[Turtle59]

Another vote for a fuel restriction. Sounds to me like the fuel supply is not able to keep up with the engine during heavy load.

If you have an OBD2 reader there will be a low fuel pressure code stored if this is the case (this code does not throw a check engine light, though)

I have a scan gauge in my Nissan Patrol... Will that work in the Canter??? I thought the Canter was Mutt 3 or some other strange system.

 

[Turtle59]

Thanks gentlemens, I will investigate all the theories above and get back to you. Saturday will be a big day.

 

[Turtle59]

OK gentlemans

I have replaced the fuel filter, the old one looked spotless, no water, no debris of any sort. It had done about 7000kms.

But here is a question and an observation... I had a good look at the primer pump on the injector pump. All looked good. Nice and clean and dry all around and no signs of any leakages or anything else untoward. Then I unscrewed the primer pump and started pumping. Now this is where the question comes... Is it normal for diesel to leak out around the shaft of the primer pump as you pump it up and down??? Or is this a potential problem that could be the root of my issue???

Thanks for your help with this.

 

[selfy]

my FG637 (4.2 manual injection) will do that as well, but it cruise's along the highway all day just fine
I had an older truck (FK415) with the old rubber tube at the top of the tank as a breather a little bug decided to make the tube its home
the symptoms were as you described, drive for a bit then seem to run out fuel, stop for a bit then it would go I found the little bugger removed the hose and it was all good
the 637's have a little manual breather screwed into the top of the tank just remove it and check that its not blocked
hope this helps
cheers Selfy

 

[Thirsty Dog]

Just experienced a similar problem between Barkly Homestead and Isa on our trip around and around Australia. I've fitted EGT & Boost Gauges & felt our Thirsty Dog dying in the ******** cruising on flat road. We tow a 3 ton caravan and have a laden weight of about 4.5 ton for the truck. I noticed the boost fluctuating from 10 psi at the manifold to 5 then 2 and up down with the attendant power changes. 50 click cruising speed is slow even for a 649! Stopped at the NT/QLD border I drained a full canister of H2O and removed some yucky black stuff from the unit. I've just replaced the fuel filter (full of skit) so hopefully it will be ok when we head off to Karumba in the morning!