car only starts sometimes

[daveid]

I went over to start it this morning and it fired right up. Within about 5 seconds it died. I started it back up and ran for about 3 seconds. started it up again and it went for about 1 second. After that it wouldnt start anymore. each time it died it stumbled to a halt. Does that info help?
Thanx again shorod for all the help

[shorod]

To properly diagnose it you'd want to confirm battery voltage to the fuel pump when the key is first turned to Run (or at least battery voltage from the inertia cutoff switch) and check fuel pressure while acting up. If I were just going to shotgun something though, I'd probably start with the fuel pump. It's a lot of work though if you're not sure it's the problem.

-Rod

[serge_saati]

Originally Posted by daveid

I went over to start it this morning and it fired right up. Within about 5 seconds it died. I started it back up and ran for about 3 seconds. started it up again and it went for about 1 second. After that it wouldnt start anymore.

It's exactly what happened when my fuel pump failed in my Windstar.

Instead of checking fuel pressure, try the current test. Remove the big fuel pump's fuse (20 amps) under hood, and connect an ampere-meter at the place of the fuse. Ask someone to turn key to run. If you read a steady current (like 7-8 amps) the pump is bad. Especially if you don't hear it priming.

[daveid]

ok. I went out today to start checking stuff again and do another fuel pressure check since it wouldnt start, and now the fuel pump isnt turning on. After i relized that, i checked the fuel pressure which of course was at 0. I then sprayed starter fluid in the intake again, and it wont run anymore sincwe the fuel pump isnt working. Im going to do a voltage test tomorrow but im not completly sure exactly how to do it and what the amps should be. Do I test the plug going into the fuel pump while the key is on? \
Where would i buy a ampere-meter? ive never used one before and how acurate of a test is that?

thanks

[serge_saati]

The digital multimeter includes voltmeter, ampere-meter and ohm-meter in a single tool. The whole tool cost just 15-20$ at any tools/electro store.
To use the ampere-meter, select 10A DC range (the line and dotted lines symbol for DC).
Then plugs the red wire to 10A plug and black to the COM. It's very accurate.

Remove the big fuel pump fuse under-hood, and connect ampere-meter lead to the contact where the fuse goes. And turn key to ON.

I found ampere-meter more practical to test pump than voltmeter. Cause if you read current, it means that you don't have bad contacts but the pump propellers are broken.
And you don't need to remove the gas tank or anything, since it's the same current everywhere.

If you have a steady 7-8amps and no prime, the pump propellers are broken. No need further test.

If you read 0 amp, it worths to test voltage at many place to see where is the breakdown. Maybe a bad contact, or a bad realy... You can just swap relays to test it.

[shorod]

If you see zero current draw, I'd switch to voltage and confirm battery voltage to the pump from the inertia fuel pump cutoff switch. From my experience the failure mode of the fuel pump is not so often the impeller but instead an open circuit in the fuel pump, likely worn brushes (similar to why starter motors fail). If the brushes stop making contact with the commutator there will be no current draw (open circuit) but that doesn't mean that voltage is not making it to the pump. If the pump is still running but the impeller were broken, you should be able to hear the pump running when the key is turned on and therefore you shouldn't need a current meter to tell you that. If the pump is seized up though and not an open circuit, you will get significant current draw and not hear the pump run. Personally I'd start with the voltage check at the inertia cutoff switch and fuel pressure. If you have voltage and no pressure, I'd say it's probably a 90% chance the pump is the cause.

-Rod

[daveid]

thanks guys. i went and tested the interia switch and it read 6 volts. we went ahead and replaced the pump and fired right up and ran. thanx for all the help on me tryoing to figure it out.

david