long crank to start, runs smooth

have a 1995 explorer with 150k on it, recently it has been a little slow to start, today it just wouldnt start. I cranked and cranked and it would turn and turn and not start, let it sit for about an hour and same thing. finally decided to start checking things and I pulled the fuel pump large black fuse under the hood and shook it and put it back in and it started. Still though it took about 10 seconds on the key.

Once it is started it runs smooth, idles perfectly like a kitten at 500rpm, and if I rev it and let off abruptly it doesnt sputter but just smooths back to its normal idle, so I am guessing that the its not anything electrical plugs wires and so on.

Any ideas? My thought process says first I should run some fuel injector cleaner because I cant remember the last time it was done, and maybe the injectors are just gummed up and not getting enough fuel to ignite and it flooded and then i let it set and tried again and by holding down it got enough and sparked...

Next step I guess I will have to start replacing and checking pieces but I would rather have a good place to start.

Oh and the check engine light isnt on so I dont guess there is a code to read.

Thanks in advance for all the help.

Have a fuel pressure gauge installed and watch the fuel pressure when you shut off the engine. It should hold pressure for about 10 minutes. If it drops more than 5 psi in 10 minutes, I would suspect the check valve in the pump is bad allowing the fuel to bleed back into the tank when shut off. Next time you try to start it, turn key on for 3 seconds, off, then on again for 3 seconds, then off then on for 3 seconds and try to start vehicle. If it starts up easily, the fuel pump is weak. Replace the fuel filter while you are there.

Have a fuel pressure gauge installed and watch the fuel pressure when you shut off the engine. It should hold pressure for about 10 minutes. If it drops more than 5 psi in 10 minutes, I would suspect the check valve in the pump is bad allowing the fuel to bleed back into the tank when shut off. Next time you try to start it, turn key on for 3 seconds, off, then on again for 3 seconds, then off then on for 3 seconds and try to start vehicle. If it starts up easily, the fuel pump is weak. Replace the fuel filter while you are there.

Also, you could have a fuel pump relay going bad, causing an intermittent no start.

Hey way2old, is that an official fuel pump leakdown test? I had not heard that. Makes sense, I'm just wondering if its officially blessed by the great autogod Ford. Or is that street smarts?

many, many, many years doing this. (why you think I go by way2old? :lol2: :eek7: ) It is an easy way to see if the pump is bleeding off. Works on any in tank pump too.

my old 250 did the same thing a few years ago. thought it was the pump. actually it was a pressure relief diaphram in the return line to the tank. sets on the fule rail at the fire wall. supposed to open at 40 psi and relief back to the tank. it was stuck open and leakking back in 1-2 hours. i also do the on- off- on- off with the key to get the pump to build up. works good, but a bad psi relief can make it look like a bad pump. sounds like your pump does work o.k. once started.

many, many, many years doing this. (why you think I go by way2old? :lol2: :eek7: ) It is an easy way to see if the pump is bleeding off. Works on any in tank pump too.


Street smarts. I've never seen anything official about how long the Ex's should hold pressure after shut off. Just curious. Thanks!

ran some injector cleaner that day and not one problem since, starts perfect, will keep in mind the other items in case it comes back to haunt me. Thanks Everyone

Street smarts. I've never seen anything official about how long the Ex's should hold pressure after shut off. Just curious. Thanks!

Hey exploded99. I am assuming you have a 99 Explorer. Here is a test directly from the 99 Explorer manual. It says 1 minute, but we adopted a longer time frame since we are government employees. :grinyes:


HC5 CHECK FUEL PRESSURE LEAKDOWN
Observe Warning, Caution and Notes.
Fuel pressure tester installed.
Key on, engine off.
Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure.
Key off.
Verify fuel pressure remains within 34 kPa (5 psi) of the maximum fuel pressure for 1 minute after the fuel pump is turned off.
Does the fuel pressure remain within 34 kPa (5 psi)?

well problem is back and the 3 second on 3 second off back on and key is only working sometimes.... what would your diagnosis be, how much will the parts cost and how hard to do the work myself

Hey exploded99. I am assuming you have a 99 Explorer. Here is a test directly from the 99 Explorer manual. It says 1 minute, but we adopted a longer time frame since we are government employees. :grinyes:


HC5 CHECK FUEL PRESSURE LEAKDOWN
Observe Warning, Caution and Notes.
Fuel pressure tester installed.
Key on, engine off.
Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure.
Key off.
Verify fuel pressure remains within 34 kPa (5 psi) of the maximum fuel pressure for 1 minute after the fuel pump is turned off.
Does the fuel pressure remain within 34 kPa (5 psi)?

So my guess is that these tests usually atke most of the morning, finish up just about lunch time?

Just kidding.

well problem is back and the 3 second on 3 second off back on and key is only working sometimes.... what would your diagnosis be, how much will the parts cost and how hard to do the work myself

Are you also posting as JoeDiana about the antitheft problem? Is that what 3 off 3 on means? If so, post under that thread....

Slow start was the topic here.

Let's go back to step 1. Install fuel pressure gauge and see what fuel pressure is when it is hard to start. If pressures are low, it is either the regulator or the pump. You can unplug the regulator and look for fuel in the line. Really need the pressures to help any more. Fuel system may be OK and we need to look at the ignition. Post pressures and we will go from there.

Hey exploded99. You are getting there. :naughty: If you play it right, you can make quitting time on a run problem. :lol2: :lol2:

I am having problems with it taking a bit to start as well (usually only when cold). Not sure if it's related, but I crank my engine for about 5sec, then when I crank it again it starts right up. This might be something to try until you get the problem solved.

took it to the shop to get it fixed, no time to do it myself. First they said nothing was wrong so i told them what to fix and how to check it.... sad, i will never use that garage again

Change your crank sensor its probably getting slow causing it to crank but not start.