For the past couple of years I've been experiencing hard starting condition on my old '87 Buick Century (3.8l). Up until recently it was most pronounced in cooler temperatures and/or if the car had been sitting for several days. Last December I had to replace the ignition module, but that didn't change the behavior. Once started, the car runs normally.
My suspicion is that it loses fuel pressure while sitting for extended periods and had to run the fuel pump to build pressure. Now the hard starting is getting worse. I have to crank the engine 2 or 3 times before it starts, but once started it runs fine and will start good for the next day or two.
Here's my biggest hint of what I think might be going on: When I get in and put the key in the ON position (before cranking), I don't hear the fuel pump run like I remember from the past. I've read that some Buick/Olds from this era had an auxilliary FP relay that was pulled in by the oil pressure switch so that if the car was in a crash (and ignition on but engine stopped) the fuel pump wouldn't be running and cause a fire/explosion hazard. This makes sense that it takes some cranking before the oil pressure builds and that would take longer in colder temperatures. Maybe I'm wrong, but I figured a bad fuel pump would show signs when the car is running (particularly on the highway) and I'm not seeing that on this car.
I'm just curious if anyone is familiar with this system and whether it might apply to my car. I have a request in for the Haynes repair manual from my local library, so hopefully that will shed some light on the problem when it's available.
My suspicion is that it loses fuel pressure while sitting for extended periods and had to run the fuel pump to build pressure. Now the hard starting is getting worse. I have to crank the engine 2 or 3 times before it starts, but once started it runs fine and will start good for the next day or two.
Here's my biggest hint of what I think might be going on: When I get in and put the key in the ON position (before cranking), I don't hear the fuel pump run like I remember from the past. I've read that some Buick/Olds from this era had an auxilliary FP relay that was pulled in by the oil pressure switch so that if the car was in a crash (and ignition on but engine stopped) the fuel pump wouldn't be running and cause a fire/explosion hazard. This makes sense that it takes some cranking before the oil pressure builds and that would take longer in colder temperatures. Maybe I'm wrong, but I figured a bad fuel pump would show signs when the car is running (particularly on the highway) and I'm not seeing that on this car.
I'm just curious if anyone is familiar with this system and whether it might apply to my car. I have a request in for the Haynes repair manual from my local library, so hopefully that will shed some light on the problem when it's available.
