1993 Taurus SHO Hard Starting

[nhra55314]

My 1993 SHO all of a sudden is starting hard. I have plenty of gas. Could it be a bad fuel pump shut-off switch.Also can you use starting fluid to try to help it along. I do not drive the car much am wondering if the gas might be bad. This just started to do this. It usually starts right off. Thanks for any help or Ideas.

[racerxpl]

Put some STP in it and see. There are so many things that can keep a car from firing right up. Your oil might be to thick if it hasn't been changed lately. A little moisture can make the spark not quite what it wants. Having your foot on the gas pedal might be overwhelming it now. on and on...

[shorod]

The fuel pump shut off turns off the fuel pump, so if you have plenty of fuel, that won't be the issue. But as racerxpl suggested, there are a lot of things that can cause the hard starting. First and foremost would be to make sure it is not due for a tune up. If it has been awhile, then you might have worn spark plugs or old wires. Also, non-OEM spark plug wires have been known to not seal as well against the valve cover gaskets and allow moisture in to the spark plug wells. Also, with the age of the car, the spark plug well seals may be leaking and allowing oil in to the spark plug wells. Water or oil in the plug wells though will often cause slight misfire conditions as well.

Do you by chance have, or was there previously, an oiled air filter installed, such as a K&N? If so, the MAF sensor may be contaminated and if you're lucky, a good cleaning may fix it. I experienced this on my former '93 SHO with a K&N. A few months after I cleaned and (over) oiled the filter, my fuel economy dropped considerably. The car ran great, but was sucking gas. I checked the spark plugs, wires, IMRC, etc. and everything was fine. For the heck of it I pulled the MAF sensor and cleaned the elements. Immediately the fuel economy climbed back to where it should have been. Before the cleaning the MAF elements were dark gray. When cleaned with electrical parts cleaner and a cotton swab (not recommended unless you are VERY careful and no one is likely the startle you) the elements were more like a titanium gray color. Now there is MAF Sensor cleaner in a pressurized can. I'm not sure how well it would have worked in my situation, but it would certainly be worth a try.

-Rod

[shorod]

Based on your visitor message, I think I misinterpreted your "plenty of gas" comment. Were you meaning that the fuel tank is not low? I interpreted that there is gas getting to the injectors but the car still doesn't start. Assuming now that you mean the tank is not empty, yes, you could try starting fluid or some throttle body cleaner to see if that helps the car start. If the car momentarily starts with the cleaner and will run as long as you are metering it in, then the problem is not with spark. The better alternative though would be to get a fuel pressure tester and attach it to the fuel rail to see if the fuel pressure is within specs.

If the fuel pressure is low, then you might consider changing the fuel filter first to see if that helps. If that doesn't help, then you probably have a weak fuel pump.

If the fuel pressure is basically non-existent, then check the fuel pump inertia cutoff to see if you have voltage to both sides of it. If there is voltage to both sides, that pretty much condemns the fuel pump. If there is not voltage to either side, then you may be looking at a fuse or a CCRM issue.

The MAF sensor will be the box with 3 wires going to it that is located between the air filter housing and the throttle body.

-Rod