So I'm driving home one day and notice my oil pump gauge flickering and tweaking out, then sticking in one place for a minute, and then flickering up and down again. My mustang sounds fine and no other gauges are doing this. Next morning, it won't start. It cranks, and the battery has plenty of power, but I don't hear that familiar electric humm of my fuel pump coming on. I had my fuel pump replaced a little less than two years ago, so I'm kinda mad it might be that again. So now I'm getting rides around for two days and riding my bike until I can have it looked at. Uncle of mine thinks it might be a bad fuel pump relay, which is under the driver seat. He brings over a new one. So before he goes to unplug the old one, I try it again and it starts right up. So I'm driving it around for two more days and then it won't start again, always seemingly at the most inconvenient time, right after class on a freezing night. The same thing: no action from the fuel pump. So I'm balancing on my head in my back seat to get at the fuel pump relay box, unplug the old one, and plug in the new one. Well that didn't do anything. Plugged the old one back in, still nothing. So I get a ride home. The car is there in the parking lot for a day. I go up a day later and it starts right up! WTF?
What might be going on here? My car is sitting in my driveway for fear of driving it somewhere and having a repeat.
So I'm driving home one day and notice my oil pump gauge flickering and tweaking out, then sticking in one place for a minute, and then flickering up and down again. My mustang sounds fine and no other gauges are doing this. Next morning, it won't start. It cranks, and the battery has plenty of power, but I don't hear that familiar electric humm of my fuel pump coming on. I had my fuel pump replaced a little less than two years ago, so I'm kinda mad it might be that again. So now I'm getting rides around for two days and riding my bike until I can have it looked at. Uncle of mine thinks it might be a bad fuel pump relay, which is under the driver seat. He brings over a new one. So before he goes to unplug the old one, I try it again and it starts right up. So I'm driving it around for two more days and then it won't start again, always seemingly at the most inconvenient time, right after class on a freezing night. The same thing: no action from the fuel pump. So I'm balancing on my head in my back seat to get at the fuel pump relay box, unplug the old one, and plug in the new one. Well that didn't do anything. Plugged the old one back in, still nothing. So I get a ride home. The car is there in the parking lot for a day. I go up a day later and it starts right up! WTF?
What might be going on here? My car is sitting in my driveway for fear of driving it somewhere and having a repeat.
1990 convertible, BBK CAI, Aluminum radiator, high-flow water pump, Tri-Ax short shifter, adjustable clutch cable with aluminum quadrant. In the garage working on the turbo kit.
1989 Hatback, BBK CAI, BBK equal lenght headers, aluminum radiator, high-flow water pump, aluminm driveshaft, short shifter, off road h-pipe and 44 flowmasters. Daily driver...getting 14 mpg YAYA!!!
You said after it's gotten cold... what it probably is, is the EEC power relay. I've had the same problem when it got cold, the power relay would polarize itself and not work till it got warmer. The power relay is down below the computer in the kick panel and looks exactly like the relay under the seat. This is the part that sends power to the relay under the seat so if it isn't working, the one under the seat won't have power coming to it.
__________________
MOOG Certified Tech. For mods and sound clips, see profile and gallery.
Ask me why I ran "only" a 13.54.
Member: NMRA Member: White Mustang Registry #362 Member: Fuzzy Dicer
So I'm driving home one day and notice my oil pump gauge flickering and tweaking out, then sticking in one place for a minute, and then flickering up and down again. My mustang sounds fine and no other gauges are doing this. Next morning, it won't start. It cranks, and the battery has plenty of power, but I don't hear that familiar electric humm of my fuel pump coming on. I had my fuel pump replaced a little less than two years ago, so I'm kinda mad it might be that again. So now I'm getting rides around for two days and riding my bike until I can have it looked at. Uncle of mine thinks it might be a bad fuel pump relay, which is under the driver seat. He brings over a new one. So before he goes to unplug the old one, I try it again and it starts right up. So I'm driving it around for two more days and then it won't start again, always seemingly at the most inconvenient time, right after class on a freezing night. The same thing: no action from the fuel pump. So I'm balancing on my head in my back seat to get at the fuel pump relay box, unplug the old one, and plug in the new one. Well that didn't do anything. Plugged the old one back in, still nothing. So I get a ride home. The car is there in the parking lot for a day. I go up a day later and it starts right up! WTF?
What might be going on here? My car is sitting in my driveway for fear of driving it somewhere and having a repeat.
The oil PRESSURE (not pump) gauge has nothing to do with your fuel system whatsoever. You need to get a good aftermarket oil pressure gauge and sending unit to fix THAT problem.
Well if the problem is intermittent, then it's most likely not the relay. If the relay goes bad it stays bad, not on and off like what you're experiencing.
When the problem DOES pop up it's ugly head and you don't hear the fuel pump, then it's probably the fuel pump itself going bad. Or you have a loose connection somewhere.
If that relay is under your seat and your tired of standing on your head, why not make your life easier by taking the seat out???? Just a suggestion...
Electrical problems are THE worst. So don't let it get you TOO frustrated.
__________________
-1994 Mustang GT... K&N filter,GT40 tubular intake,BBK Full Length Headers,modified midpipe & Flowmaster muffs, timing at 12*. Best time- 14.74 @ 93.16 -Check profile for pics of our car collection! -Member of MBMCustoms Car Club - AmericanMuscle ROCKS!! - "Save a horse, drive a Mustang!"
Haha, if it were in my driveway then yea, but it was 10 at night in a parking lot with no hand tools. It was very frustrating and I do recall having to close my eyes and count to ten. Thanks for everyone's input, by the way. So the engine cranks strong, it just doesn't start. Uncle pulled like a fuel line off it showed no fuel. He said it would spray out a bit if there is pressure.
Interesting, the first time it didn't start it was on a very cold morning. Second time was on a very cold night. I also just want to say that when I was balancing there on my head in the backseat that night, trying both the new and old relays, I did manage to reach up and turn the ignition and I did hear a faint, yet audible (electrical?) click coming from both old and new relay there under the seat. Does that mean the problem is further down the line?
So about two years ago my last fuel pump went out. Well, when it did go out, it let itself be known. At first, the hum of the fuel pump sounded out of tune. Next time it was worse. Next time same thing, and it sputtered and died halfway down the road. Do all fuel pumps die like this? I replaced it with an aftermarket bbk fuel pump (110lph) with more flow, in anticipation of the motor oneday needing the actual extra fuel. - and the aftermarket pump was actually cheaper than the stock unit! MEchanic said it wouldn't make a difference. You guys still think its the fuel pump or the EEC?
Is it a Fuel Pump Problem??? 
