Serial number 27407. 25k hours. It’s got the dreaded 96-1 code. Fuel injection failure. 2 different operators run it. Operator A drives it like a rented mule and he has zero problems. Operator B idles around the log yard and constantly has to restart it to get the code to go away. I’ve been chasing this issue for a few months. Everything except the rail relief and pressure sensor had been replaced so I started there and the issue was cured for about a month. Then it returned. I talked with the dealer (that I used to work for) and they looked at the history. The fuel control valve was the oldest part so we threw one at it. Problem solved. For about 2 months. Next thing I found was the belt driven supply pump. Bearing had play in it so I put one on it. Nope. I suspect the injectors are flowing too much fuel and need replaced but the cost is $7000 and I’m not doing that on a hunch. Back when I was a field tech for Volvo we had a hand drawn diagram of the fuel system and it showed how to diagnose the fuel system. i didnt keep my diagram when I quit and nobody at the dealer seems to recall anything about it and they are not willing to help. What I’m looking for is where to tee into the system to measure fuel flow on the injectors and what is the allowable amount? I have prosis but can’t seem to find it. Thanks in advance.
I had an L90F that had similar issues every thing had be changed. Finally found a bad cam & follower on one of the high pressure pumps. I also had the valve for injector leakage but can’t find it. I do recall using a Gatorade bottle and and I had a line on it about an inch or or two up on a 32oz bottle for 1 minute run time. If the bottle filled halfway or more I would install new injectors. Sorry I don’t have more specific information. Hopefully someone can get you the proper specs
Sorry value not valve for injector leakage
If I recall the injector leakage info was in a product improvement bulletin and not directly in service section. I think there was some information in service side for G model but I’ve slept since then so don’t hold me to it.
the diagram we all had was hand drawn by one of the older shop techs. It showed where to tee into each section of the fuel system and what result you should see. The 96-1 code was always a pain because it could be anything from filters to injectors. All the field trucks had multiple test parts for when you needed to run swapnostics.
This may help you
Fitting
If you test return flow with just that fitting and do not provide a return for the overflow valve back to tank you will create an issue where the overflow cannot return and it will cause the PRV to unseat and blow the return line. Also the measurements provided are just guidelines and in no way a specification.
That info will definitely work. Thanks
I think the idea of welded/brazed up the cross hole in the banjo bolt is to redirect the return fuel from the tank return line to a container so that the amount of fuel returned can be measured.
It is to divide the injector return flow from the return from the FCV/overflow valve and PRV. The flow from the overflow valve is considerably more than injector return so you do not need that skewing your measurement. It is enough that it will create backpressure and open the PRV by inducing too much pressure on the low pressure side of the valve. I have seen it happen with technicians in the past. The way to prevent this is to connect the return to tank to the fitting on the FCV for overflow return.
You could test 1 injector at a time, you block the fuel supply to the injector one by one and when you have less return, it is the one that needs to be changed.Sometimes it is only 1 injector that is defective. 75% of the time it is the high pressure pumps that are the problem, especially if you find metal dust in the fuel water separator bowl.
My first thought was also testing injectors individually, or pressure from fuel pump, but if its lagging and throwing at idle maybe that pump isnt being driven hard enough to send enough fuel through, causing the code? What do you guys think? Anyone figure something out?
Haven’t figured anything out yet. Radiator popped and the customer wanted to send it out to see if it could be repaired rather than spend $4600 for a new one
Thanks for sharing your non expensive tool, will give a guy a good idea how much fuel is leaking out from the injectors into a clear bottle as you suggested. Much appreciated. Simon C