Pouring fuel into the crankcase.

[Ilovelamp]

Hey guys. I've got a '12 qx56. It has been a year since I have even tried to work on this thing and I'm losing patience again... Last year it started losing power and spitting and sputtering. The codes were for the cats. So with that info, I creeped forums and found that these cats don't normally last the 240k that is on the qx. Sooo, I got with Cajun tuning and bought test pipes and headers and bought a tune from uprev.

The initial problem was the loss of power and bogging down. I had one bad injector, my wife was out of state in the qx so she took it to a shop and had an injector put in and headed back. When she got back it absolutely would not turn over. Had a horrible strong gas smell and when I could get it to crank it sounded like it was hydrolocking. Pulled the dipstick, the crankcase was full of fuel... Drained over 6 gallons of fuel and oil out of the crankcase. I pulled the second set of cats off hoping they were clogged and it would help.

After that, she cranked like a champ. Started, ran great then disaster... Looked under the truck and it was pouring fuel out the open exhaust. Shut it off, checked the oil and it was overful.

So for 7 months until jba built the headers it sat. I was hoping things weren't reading right because of the car issues and when the headers were put on it would run decent and then I would put the tune on and go from there. Well, headers on, started, ran, poured fuel. I can't even get it to start at this point. It almost sounds like the timing is off... I know there are a lot of issues here it seems and I tend to ramble. I really need help...

Is the high pressure fuel pump open to the inside of the block if something in it ruptures? Anyone ever had issues with injectors sticking open? I had it taken back to the shop that put the injector in hoping they had smashed an o ring but, nothing there, the injectors were all ohmed and within range. Any suggestions? This thing is in excellent condition so I'm almost ready to ls swap it and move on... I've spent well over 10k on parts and repairs since the issues began.

 

[primov8]

If you're not doing the work yourself, find another shop asap. In order to access the GDI injectors, fuel rails and high pressure pump, the intake manifold has to be removed. When that happens, the (8) individual intake manifold gaskets have to be replaced as well. I highly doubt that so called shop replaced an injector or even tested the injectors at all.

From the amount of gas you have mixing into the crankcase, it almost sounds like the piston rings/seals are shot. Find a competent tech/shop that can do a compression test. Even better if they have an engine borescope to inspect the cylinder walls and pistons.

 

[Ilovelamp]

Hey primo, I did a compression test after I found fuel in the crankcase. Supposedly they did as well. Whether or not they did, not sure, but it's been done. Every cylinder was actually on the high side of range. The shop is a performance shop that builds drag cars. I'm pretty sure they're competent but not sure they want to put that much work in something that isn't an LS drag car... This is the first time in my life I've ever let someone else work on my vehicle so I'm not happy about the situation at all... I know on my direct injected diesel, the fuel pump diaphragm ruptured and filled the crankcase at one point. So I'm curious if that can be what is going on. Nissan won't touch it now because it has headers and no cats.

So, that being said, the compression is great on all cylinders. I have a few things going on and I'm hoping to get help before I tear it apart and do it myself like I should have.

1. Timing?
It has occasionally had a hard start where it would act hydrolocked. Hit the start button a couple of times and it would go ahead and crank over. Maybe once a month or every couple of months.

2. Fuel pump?
Now it is dumping fuel, it is either pouring through a busted diaphragm in the fuel pump or washing by the rings, since the compression is so good, I am hoping that is the fuel pump

Is there anyone who is on the forum that has experience with the pumps and would be able to tell me if there is a known problem with them leaking into the block?

 

[primov8]

The only issues I've heard or read about in regards to the high pressure fuel pump is this:

https://www.facebook.com/a1stratemobile/posts/1096627593704661

By the way, peep this thread I had posted awhile back. From the pics I posted, you can see how much work is involved not only to get to the fuel rails and injectors, but to actually even test them requires removal of just about every fuel line running to the rails.

P0171/P0300. Fixed.

I haven't been able to post/update as much on some of my favorite forums because my wife and I both work in healthcare and its just been ridiculously crazy. I finally got some time off and decided to post up my latest mods and past fixes. I hope this helps out any forum members who may have...

infinitiforum.net

If I were in your shoes and not getting anywhere, remove the intake manifold and tackle this via DIY. Download the OE service manual and believe me, much easier to diagnose if you have access to a full range scan tool.
One thing that can be overlooked is the fuel pressure regulator. Unfortunately, that is located on the driver side fuel rail and at this point, I'd even have the GDI injectors tested if you have a local shop that can do so.