Engine flooding BADLY

[AmTeC]

So I've been driving my CB7 for a few days since I got it back from the body shop. I've notice the fuel economy has gotten SO BAD that while driving it for 20 minutes in stop and go traffic, the fuel needle has visibly moved towards the E. No its not because the gas sloshes around and make the sender go up and down, after stopping at a gas station I can confirm it actually used up all that gas. Last week, 45 km used up a quarter of a tank There are NO gas leaks as far as the tank and lines go. It passed the E-test a few months ago when the fuel consumption was bad but not at this level quite yet. The exhaust doesn't smell weird. The engine doesn't hesitate when flooring it or just normally driving in traffic. However, when it returns to idle the engine RPM dips ever so slightly for a second and the engine vibrates like its gonna stall, for like less than a second. There is no CEL. The engine has had a habit of flooding if I prime it more than once, I know for a fact the system can't hold fuel pressure overnight. The engine has been stopped and started about 5 times today, the first 4 were an instant start with minimal cranking. At the fifth start, the engine started and then stalled shortly after, and after LOTS of cranking, it started, I have a brand new battery and it started getting low after that much cranking, I did give it breaks to prevent damaging the starter though. Once started it seemed to run okay, I rushed home and didnt have time to check its performance. This is the worst case of the flooding yet, The flooding and bad fuel economy both got super bad today, What do you guys think? leaking injector? What else could this be if not an injector?

[Crankshaft]

Ok, first thing is to determine the cylinder that is flooding or if there is actual flooding at all; you mention trouble starting combined with loss of pressure, both of these can be caused by a faulty Fuel Pressure Regulator.

Check this in order:
1. Pull the vacuum hose from the FPR, if there is liquid gasoline present when you unplug it then the regulator is bad causing fuel to escape and get sucked into the manifold via vacuum line.
2. If there is no fuel present on vacuum hose; remove spark plug from one cylinder at a time checking for fuel present inside, you can do this visually or using a sheet of paper rolled up into the size of a pencil.
3. If fuel is present on a cylinder you know which injector is stuck open, you could also check resistance or pull them to test while off the manifold but this method is faster.

[AmTeC]

Ok, first thing is to determine the cylinder that is flooding or if there is actual flooding at all; you mention trouble starting combined with loss of pressure, both of these can be caused by a faulty Fuel Pressure Regulator.

Check this in order:
1. Pull the vacuum hose from the FPR, if there is liquid gasoline present when you unplug it then the regulator is bad causing fuel to escape and get sucked into the manifold via vacuum line.
2. If there is no fuel present on vacuum hose; remove spark plug from one cylinder at a time checking for fuel present inside, you can do this visually or using a sheet of paper rolled up into the size of a pencil.
3. If fuel is present on a cylinder you know which injector is stuck open, you could also check resistance or pull them to test while off the manifold but this method is faster.

Fuel pressure regulator eh? I didnt think of that! Can a bad FPR also cause my awful fuel economy? I tried to lookup some threads about the FPR to find a picture or diagram of where the FPR and its lines are located, but unfortunately the photobucket debacle has made finding a proper picture/diagram a problem. Where can I find said FPR and its corresponding vacuum line? Also I would assume when I check the line, the engine would have to be in its flooded no start condition.

Thanks for the quick reply, I love the CB community!

[Crankshaft]

Fuel pressure regulator eh? I didnt think of that! Can a bad FPR also cause my awful fuel economy? I tried to lookup some threads about the FPR to find a picture or diagram of where the FPR and its lines are located, but unfortunately the photobucket debacle has made finding a proper picture/diagram a problem. Where can I find said FPR and its corresponding vacuum line? Also I would assume when I check the line, the engine would have to be in its flooded no start condition.

Thanks for the quick reply, I love the CB community!

Fuel pressure regulator is on the fuel rail on the right hand side, look for something like this and unplug the vacuum hose to the curved tube on top.

images (3) by Jesus Gonzalez, on Flickr

[Crankshaft]

This would make your mileage suck big time because not only would fuel be spent being ignited but also sucked thru the vacuum line and have bad idle too.

[AmTeC]

This would make your mileage suck big time because not only would fuel be spent being ignited but also sucked thru the vacuum line and have bad idle too.

Hmm, I have AWFUL fuel economy, but the idle seems relatively smooth. I guess I won't know for sure until I start taking things apart.
EDIT: When I say smooth I mean it doesnt feel like its going to stall most of the time, RPM stays constant, It does vibrate alot at idle, and because of my bad engine mount, so does my steering wheel, Although if I recall correctly, the vibrations at low RPMS on a 4 cylinder engine are perfectly normal.

[Crankshaft]

Hmm, I have AWFUL fuel economy, but the idle seems relatively smooth. I guess I won't know for sure until I start taking things apart.
EDIT: When I say smooth I mean it doesnt feel like its going to stall most of the time, RPM stays constant, It does vibrate alot at idle, and because of my bad engine mount, so does my steering wheel, Although if I recall correctly, the vibrations at low RPMS on a 4 cylinder engine are perfectly normal.

When talking vibrations we must take into consideration the balance of the rotating assembly, while 4 cylinder engines have less pistons to counteract each other we must also consider the physical specifications of said motor. An engine whose characteristics are more square will inherently suffer less from vibration than en engine with a longer stroke to bore ratio; our F22 have stroke close to that of a 383(3.74 vs 3.75) than the average 4 cyl, this limits revolutions but increases torque at low RPM. I have had a couple 4 cyl that you would not even realize they were on if you were blindfolded

[deevergote]

What do your spark plugs look like? If you are seriously overfueled, they will be fouled.

Your injectors can't be leaking fuel into your engine to a significant degree while the car is parked, because you'd end up with internal damage as soon as you tried to start the engine (liquid fuel, like water, doesn't compress, and will destroy anything that tries to compress it.)

Anyway, pull your plugs, examine them, replace them with new, drive for a bit, pull them again, and see what's going on. From your description, it still seems likely to me that there's some sort of leak. The engine seems to be running well enough, and although you didn't provide any real numbers, your fuel economy seems poor enough that you would be witnessing some serious engine problems. Your o2 sensor should be freaking out, or just about fouled by now as well if you were seriously overfueling. Your exhaust would be blowing black smoke, and you'd definitely be able to smell it.

[AmTeC]

What do your spark plugs look like? If you are seriously overfueled, they will be fouled.

Your injectors can't be leaking fuel into your engine to a significant degree while the car is parked, because you'd end up with internal damage as soon as you tried to start the engine (liquid fuel, like water, doesn't compress, and will destroy anything that tries to compress it.)

Anyway, pull your plugs, examine them, replace them with new, drive for a bit, pull them again, and see what's going on. From your description, it still seems likely to me that there's some sort of leak. The engine seems to be running well enough, and although you didn't provide any real numbers, your fuel economy seems poor enough that you would be witnessing some serious engine problems. Your o2 sensor should be freaking out, or just about fouled by now as well if you were seriously overfueling. Your exhaust would be blowing black smoke, and you'd definitely be able to smell it.

It seems to take about 8 hours for the pressure to completely bleed out, My guess is that the gas evaporates long before it pools up in the cylinder. I know there's no fuel line/tank leak, the tank is brand new and any rusty lines were replaced, there isn't any gasoline odors present. And yeah, I find it really weird that the engine's running fine and the performance hasn't visibly dipped much, exhaust smells fine too

[deevergote]

The fuel is going somewhere. Either into the running engine, into the non-running engine, or leaking out before it gets there. Fuel evaporates fairly quickly, but a significant amount of evaporation would take a good deal of time (in ideal conditions for evaporation, days... in a semi-sealed system such as your tank, weeks or months.)
If your injectors are leaking into your engine, that would likely accelerate the process. However, they would need to be doing so slowly enough for each drop to evaporate before the next one arrives. Being inside the engine (away from external sources of heat, wind, etc...) that would also take a good long while. If the injectors are leaking any faster, there would be an accumulation of fuel in the cylinders. The result would be either hydrolock (as I described before), or contamination of your oil as the fuel seeps past the piston rings. That would lead to slower engine death, but engine death nonetheless.

I'm wondering if there is perhaps a leak that is only present when the car is driving. If the car is moving while it's pissing fuel, you may not notice the smell. If it stops when the car is at idle, you won't notice it.

As I said, your fuel is going somewhere... and it seems to be going somewhere rapidly.
Since your engine is running pretty well for the most part, I'm still leaning toward an external leak. The replacement of the tank and lines introduce multiple points of potential leakage. Any time something is touched by human hands, the potential for failure increases.

Inspect your plugs as I mentioned before. Then take your car to a secluded empty parking lot. Bring a friend along. Drive around the lot. High speed, low speed, partial throttle, full throttle... put the car through the paces. Have your friend watch for leaks and/or smoke. Then switch places. Have your friend drive, and you stand back and watch.

[AmTeC]

It seems to take about 8 hours for the pressure to completely bleed out, My guess is that the gas evaporates long before it pools up in the cylinder. I know there's no fuel line/tank leak, the tank is brand new and any rusty lines were replaced, there isn't any gasoline odors present. And yeah, I find it really weird that the engine's running fine and the performance hasn't visibly dipped much, exhaust smells fine too

NEW DEVELOPMENT

I feel like an idiot

Im pretty sure its an intermittent fuel pump problem, I tried to "flood it" on purpose by priming it, I noticed that every few times I turn the key, once in a while, I dont hear the fuel pump come on, D'oh! and its then that the car starts up and stalls shortly after. Still doesn't explain my fuel economy, and my fuel pressure dropping overnight though, I checked the vacuum line for the FPR and there wasn't any liquid gasoline in it after running the car to operation temp. I dont know where to start looking, I don't see the fuel pump relay printed on any of the fuse box directories. How can I test the fuel pump itself? Also yeah... Maybe there is an external leak in that case, On the highway it seems to just sip gas, but it guzzles it during stop and go, I guess when I come to a stop, theres a possibility that its sloshing out somewhere. I was driving around a lot yesterday though, practicing for a driving test, the fuel was dropping pretty quickly, but I didnt notice any gas puddles as I went around slowly, but maybe I just didn't notice.

EDIT: I reflowed the solder on the relay, and so far, so good. Now to find the cause of my terrible fuel economy!

[AmTeC]

What do your spark plugs look like? If you are seriously overfueled, they will be fouled.

Your injectors can't be leaking fuel into your engine to a significant degree while the car is parked, because you'd end up with internal damage as soon as you tried to start the engine (liquid fuel, like water, doesn't compress, and will destroy anything that tries to compress it.)

Anyway, pull your plugs, examine them, replace them with new, drive for a bit, pull them again, and see what's going on. From your description, it still seems likely to me that there's some sort of leak. The engine seems to be running well enough, and although you didn't provide any real numbers, your fuel economy seems poor enough that you would be witnessing some serious engine problems. Your o2 sensor should be freaking out, or just about fouled by now as well if you were seriously overfueling. Your exhaust would be blowing black smoke, and you'd definitely be able to smell it.

I took your advice and drove it around a parking lot aggressively, I slammed the brakes, I floored it, I took hard lefts and rights, Then looked under the car for gas leaks and smells. Nothing, nothing at all.

On a side note, today I drove the same distance I did yesterday and the fuel economy wasn't nearly as bad as yesterday, Still not great though.

I checked the plugs of cylinders 2 and 4, My dad wanted me to move my car out of the way so I didnt get time to check 1 and 3. The plugs aren't fouled, they seem fine, Cylinder 2's plug seemed a little more worn but nothing serious. I plan on cleaning out the EGR and other emission related crap to see if that helps