Fuel vapor from catch can?

[MindlessR33]

Hey everyone, 

So I just finished wrapping up a build on my R33. New turbo, injectors, exhaust mani, cut and shut intake, etc...

We did some street tuning and overfilled the catch can. After cleaning up the mess we realized there was a lot of vapor coming the catch can breather. Checked the oil and it smells like fuel. 

I primed the fuel rail and there's a buzzing noise coming from the injector for cylinder 3. Cylinder 3 also smelled strongly like fuel  when I removed the plugs. I'm assuming the injector got stuck open somehow, so I'm having them tested and cleaned. 

Going to compression test it in two days when I get back home. Assuming it tests well an, any thing else I should do before putting it back together and starting it back up once I get the injectors back? 

[Duncan]

Yes, change the oil. And before that, check the oil level as a major fuel leak to the sump will show up as overfilled oil 

It will be pretty obvious if the oil is fuelly. 

[Dobz]

If there was vapor coming out due to crankcase breathing you might want to put an inspection camera down the plug holes and check for a potential glazed bore. If no.3 was getting washed down with fuel there might be some excessive cylinder wear.

[MindlessR33]

Changed oil, full of fuel. Did compression test and it looks bad. Cylinders 1, 2, 4, 5 & 6 all had 80-90psi. Cylinder 3 had 155 psi. Will be doing a leak down test this weekend when I get back home. I'm guessing the tuner leaned out the other cylinders while that injector was dumping fuel into the cylinder.

[MindlessR33]

On 5/18/2022 at 10:06 PM, MindlessR33 said:

Changed oil, full of fuel. Did compression test and it looks bad. Cylinders 1, 2, 4, 5 & 6 all had 80-90psi. Cylinder 3 had 155 psi. Will be doing a leak down test this weekend when I get back home. I'm guessing the tuner leaned out the other cylinders while that injector was dumping fuel into the cylinder.

So I bought another compression tester to double check. 

150-160 on all 6.

[Duncan]

good choice!

so, almost certainly injector was stuck open. clean/test or replace injector, problem solved.

How was it running BTW? It should have been missfiring with that much fuel in cyl 3

[Duncan]

Sorry, I should add, you may have troubles bedding the rings on cylinder 3 if you have had an injector problem. It is probably worth getting it on a dyno to run the engine in once the injector is sorted  as it may never break the glaze on the bore with just street driving

[MindlessR33]

Just an update on this. Much more was wrong. Tuner messed up and set boost to 22psi and cut fuel like crazy working around the stuck injector. Something must have been wrong with my compression tester because I bought another one the next day and I had 50 or less psi on all cylinders except #3 and that's the one that had the stuck injector. 

Tore it down and pistons 1,4,5&6 had cracked ring lands. 

Almost finished rebuilding now with CP pistons and Manley rods though. 

[Duncan]

Well that is a nasty end to the story. All the best getting better workmanship next time.