Update for folks:
I changed the oil today, and upon removing the drain plug I was blasted with a whiff of gasoline. To be sure it wasn’t a fluke, I sniffed the oil-soaked glove I had on and sure as hell, it reeked of gasoline. One more check, I smelled the oil dipstick, and it too stank of gasoline.
So apparently I’m getting gasoline into my oil. I figure that means one or more leaking injectors, or a bad pressure regulator. Can the pressure regulator be leaking and need replacement even though there is no fuel in the vacuum line for it? Other thoughts?
Phocylides,
Removing the fuel injectors, as a group, to determine which one is leaking (into the intake manifold) is one way. On your V8 it may be quite a bit of work.
The problem may be gunk built up on the fuel injector nozzle (pintle). A cleaner, going through the fuel rail, through the injector, may be enough to remove the gunk which is keeping the fuel injector from closing completely. A fuel injector cleaner, added to the gas tank, may be sufficient. If not, you need something more direct and concentrated.
You could get the fuel injector cleaning kit, and do it yourself; or, for about the same price, have a garage (Sears, etc.) do it. Here’s a kit: http://iecoklahoma.com/fick.aspx
Yeah, I certainly wasn’t looking forward to removing the fuel injectors. Definitely a weekend job for me. I tried a fuel injector cleaner a few weeks ago when I did the plug and wire change, and I don’t think it did the trick. If I can find a shop to do a more direct cleaning like you suggest, for $80 (the cost of that kit) I’ll start there first. If that doesn’t work, I’ll attempt the work on the injectors. I’ll let you guys know what comes of it all : )
Budd, with a leaky injector, maybe the fuel is leaking down while the car is off, and seeps by the rings? I also read about a faulty PCV valve allowing unburned gas to mix with the oil. Or bad rings? That seems to be the only way gas can mix with the oil right?
Today I removed the spark plugs after allowing the engine to run for a minute, and did a sniff test on the plugs. They all had at least a tiny bit of fuel odor, though the #1 plug was a little bit stronger than the others. None were wet with fuel, and no plug had sooty deposits on it like I would’ve expected. And just for grins, I ran a compression check (1 to 4: 170, 165, 170, 160).
So at this point I’m guessing that, if any injector is leaking, it could be #1. I’d expected a real strong fuel odor from that plug and didn’t get it, so I don’t know. Pain in the butt!
I did post earlier in the thread that a GM TSB recommended a fuel injector cleaning but we all know how suspicious we are when a F.I.system cleanse is recommended.
If the fuel pressure regulator diaphram were leaking you would see fuel in the signel hose to the manifold. If the fuel pressure regulator was leaking fuel back to the return line, you would not see the flow. If you want to verify that the problem is not the diaphram, leave the vacuum hose disconnected; plug the nipple; try to start the engine; and see if fuel comes from the hose.
If you are not getting fuel in the fuel pressure regulator vacuum line but still getting fuel in the oil, the most likely culprit is an injector. Yes you can pull injectors out of the manifold leaving them still installed in the fuel rail. You will have to make sure that the injectors do not pop out of the fuel rail. When you cycle the pump you can verify which injector is leaking.
Keep us appraised of your progress and/or the solution.
The very latest:
After enjoying the flu for the last four days, I finally got around to replacing the fuel injectors on the S-10. Sure enough, the #1 injector had a nice little crack inside one of the tiny holes next to the nozzle. Installed new injectors all around, put 'er back together and it started right up without a problem.
However, it appears that I am STILL not holding fuel pressure. I was getting some readings that didn’t make a lot of sense. One time, (with ignition ON, engine OFF) it pressurized all the way to normal (45 PSI), and when the pump stopped the pressure dropped to nothing within 10 seconds. I checked things with the engine running and not running to make sure there wasn’t a fuel leak around one of the new injectors, but they’re tight and locked in.
The pressure is holding at about 39 PSI while running, pretty normal. At one point, I shut the engine off, the pressure snapped back up to 45 until the pump turned off, then it dropped to zero almost instantaneously. I turned the ignition ON, it zipped right back to 45, and started dropping again when the pump finished priming.
I haven’t driven it enough yet to know if the hard starting problem has been cured, but I’m at a complete loss to explain these fuel pressure readings. I’m starting to wonder if maybe the gauge is a little wonky.