Bad gas, rough idle, and a question about rail pressure

The Gas and Diesel Engines - VQ40De, VK56DE, YD25DDTi, V9X, Transmission, Transfer Case, Oil, Differentials, Axles, Exhaust...

Moderator: volvite

Bennettj007
Posts: 2
Joined: Sat Sep 26, 2015 7:57 am

Bad gas, rough idle, and a question about rail pressure

Postby Bennettj007 » Sat Sep 26, 2015 8:11 am

Okay, so I got some horrible gas about a week ago. 2006 pathfinder that ran fine before this fill up. As soon as I pulled away from the station the car started to run terrible. Rough idle, no power, and just bad in general. I added fuel treatment immediately and it smoothed out and ran much better, so I assumed just some water in the gas. Problem then became worse and car died and would not start. Towed home and started to diagnose the problem.

Gas was terrible, mostly water, and had debris floating in it. There have been about 30 vehicles experiencing the same problem from this station so it is definitely fuel.

I pulled the tank, cleaned thoroughly, and replaced pump with a new pump. After reinstall the engine still is not running right, but will usually start. Pulled injectors and test for spray pattern and opened with all injectors looking good.

My concern now is maybe I am not getting rail pressure. I unhook quick connect from rail and put the hose end in a jug to watch flow. There is only flow when cranking. Shouldn't the fuel pump be pumping when the key is cycled to prime the system? Is there anything between the pump and the rail that could have clogged with debris? I am pretty good at working on cars but this one is throwing me for a loop. I can hear the pump cycle and it did start after the new pump, but still acts like it is starving for fuel. I also checked the coil packs and they seemed ok and replaced plugs in case the plugs fouled with the bad gas.

The codes were p0011, p0021, and p0300 if I remember correctly. Which is random misfire and ignition problems but they did not happen until after the bad gas. Any help would be much appreciated.


Bennettj007
Posts: 2
Joined: Sat Sep 26, 2015 7:57 am

Postby Bennettj007 » Sat Sep 26, 2015 9:01 am

Just an update. I repulled the fuel rail to check it out. I didn't depressurize this time and it definitely did have good pressure. So maybe not a debris clog that is starving fuel. Now my culprit would be the injectors although it thought I did a decent job of checking them. I had pulled them, cleaned the nozzles, and used a hose to pressurize fuel while putting cycling power to see that each would open and have a decent spray pattern. I don't know if that is perfect but it would be what I would do on mechanical diesel injectors to do a pop test and spray pattern inspection.

So could my injectors still not be functioning even though they appear to be when out of the car?


Return to “R51 Engine, Driveline and Powertrain”