Cadillac Repair: 92 fleetwood 4.9l, fuel smell, engine locks up

Question
Hi,

My dad's caddy began acting strange about two weeks ago and we had to have it towed. There was considerable smoke from the exhaust and strong gas fumes inside and outside of the car. We thought that it might have been the transmission modulator causing the smoke and maybe a bad converter for the gas fumes. The modulator was replaced, and it was towed to a local muffler shop for the converter. It would not start or if it did it was unpredictable. We thought it was the starter. The starter was pulled, but it was fine. We tried starting. The motor would turn over then seem to bind. After several hits from the ignition switch it would turn over again and then stop. We checked the oil and it appeared that there gas mixing with the oil? Can you advise on any possible scenarios? Thanks for any help!

Will

Answer
Hi Will,

    Two things come to mind. First is the fuel pressure regulator that mounts in the fuel rail and has a vacuum hose going to it. What happens is the diaphragm gets a hole and that allows gasoline to get into the engine. To test for this remove the vacuum hose with the engine off and see if any gas comes out. If so replace the regulator. If no gas then with the hose off turn the key to run without cranking the engine a 3-4 times allowing 5 seconds for the computer to reset the fuel pump circuit.

    If nothing shows up there then you could have a fuel injector that is stuck open. To test for that you would need a screw on fuel gauge and a couple visegrip pliers to pinch the fuel feed and return hoses closed once the pump turns off. If the pressure bleeds down then you have a leaking injector. You could remove the fuel rail with the injectors still attached and power up the fuel pump and see which one(s) leak and replace them.

    After repairing the fuel problem make sure to change the oil and filter to get all the gas out of the engine oil. As a side note...since the engine wants to turn and stop too much fuel could be getting into a cylinder. The best thing to do would be to remove all the sparkplugs, disable the spark and fuel pump and then crank the engine to get all the fuel out of the cylinders. Hopefully nothing has been damaged.

    Hopefully that answers your question. Bill