No start and no power to the fuel pump, help!

[mikesparky]

Hi all, sorry in advance for the novel.

My 95 explorer has been down for almost two weeks. It wouldn't start, I changed the fuel pump relay, no difference so I took it to a local shop. They checked the fuel line, saw no pressure and diagnosed the fuel pump which is what I thought the problem was. They tried to charge me 500 which is probably fair, but I didn't have it so I did it myself. Connected the new pump and still no start. I checked the connector and power is getting to the connector on the car's side, but isn't getting to the pump. It was at least powering the fuel indicator, but that's it. I decided it must be the connector, couldn't find a replacement and being a little impatient at this point just stripped the wires and twisted them together to see if this was the problem. Still nothing. Now I check for current and get nothing. The CEL comes on with the key on engine off and turns out when I try to start which should be normal. Also, my battery is maybe a month old and is completely drained from trying to start and I'm guessing from prolonged use of the interior lights. It won't keep a charge and I have to get a jump just to attempt to start. Any ideas? Thanks!

 

[skoal_mint]

power probe the power wire for the pump is the first thing to ever check befor changing a fuel pump, well the relay first.

i mainly do gm fuel pumps because gm's suck so i maid myself a easy wire harness to plug into the pump connectors...should be too hard to find the problem on a explorer, theirs only like 5 feet of wire on these little truck

 

[MustangP51]

Have you checked the inertia switch?

 

[mikesparky]

Thanks guys. I've got an update. I had burned out a fuel system fuse after I originally checked them when it first died. I replaced it and now it starts up and dies under 5 seconds. I probed the power wire at the pump and it's not getting power but I definitely heard it turn on and it does start up. It could be priming and then not operating, has anyone had anything like this happen to them? Could this be a PCM problem or isn't there a component that controls fuel distribution? I've checked the inertia switch and it doesn't seem to be tripped. Do they go bad and how would I check? Thanks!

 

[MustangP51]

Check it by ( I know how this is going to sound) pounding on it until it trips. Then reset it.

 

[mikesparky]

Thanks, I'll pound on it after work. =] Assuming that's not the problem, does anyone have any knowledge about the pcm or fuel management system?

Thanks.

 

[budwich]

forget the "pounding"... just jumper it out of the circuit to get it to run.... if it still doesn't, then it ain't inertia switch (highly unlikely anyway). Since you blew a fuse that you didn't notice initially, I would check all fuses... just in case you didn't notice another fuse gone.

 

[mikesparky]

Thanks Bud, yeah I was doing a check of all the fuses when I found the bad one. Prob not a bad idea to go over them again... I agree and was thinking I could just see if there's current after the inertia switch instead of beating the crap out of it, although it might be therapeudic at this point!

 

[MustangP51]

If you want to jump the inertia switch, jump it, however the only way to test an Inertia switch is with a jolt. An experienced mechanic will know the difference between pounding on it as oppose to beating the crap out of it.

 

[mikesparky]

Hey Ryan, I wasn't trashing your idea (still plan on hitting it). Like you said it just sounds funny. I'll hopefully have an update soon.

 

[MustangP51]

Hey Ryan, I wasn't trashing your idea (still plan on hitting it). Like you said it just sounds funny. I'll hopefully have an update soon.

Hopefully its a good update

 

[skoal_mint]

if you find wire diargram, check which wire powers the pcm and check to see if theirs power coming out of it... make sure theirs a good ground

most trucks have more then one power wire going to the pcm so nows the time to be using a multi meter incase you have a corroded wire...but your getting a prime so idk

check your injectors with some nod lights while cranking the engine

 

[mikesparky]

A quick update:

I've gone over the fuses, looked at the inertia switch and all looks normal. I even removed the fuel cap on the off chance of vapor lock. It starts up and dies almost immediately. I looked at the battery cables and they seem ok, but I may switch out the positive tomorrow. One thing that's been a problem is my battery is pretty much dead, it's brand new so I think I'll switch it out at Wal Mart tomorrow and see if that affects anything. Would a really low battery keep it from running? Thanks and keep the ideas coming!

 

[skoal_mint]

fuel filter pluged?? lol worth the try

 

[mikesparky]

lol, yeah I was thinking of that too. I should change it anyway since I just replaced the fuel pump so I'll be getting one of those tomorrow too. Why not, right?

 

[budwich]

well, IF your "analysis" about "not getting power about 5 seconds" is correct, its not the fuel filter. Of course, changing it never hurts but if you want to solve the problem you need to go in a direction of "powering" when there is "no powering".

 

[mikesparky]

I agree completely, hence the battery. I'll still change the fuel filter since it should be done with a new fuel pump and only takes a few minutes. I'm definitely still focused on the power issue since I'd like my car to run sometime soon!

 

[mikesparky]

Update: Still same problem. Starts up and almost immediately dies. I've also noticed that I don't think I'm hearing the fuel pump prime now. It's hard to tell because my battery is dead and I have to jump it every time I want to try starting wich is a PITA. The car running right next to mine could be covering it up.

After searching the forum even more I discovered one case similar to mine where the pcm diode had gone bad. I tried checking it like a fuse since there are two metal tabs on either side, but didn't get a reaction. I checked another one with the same result. Two bad diodes or I don't know what I'm doing? More likely the latter! Anyone know anything about diodes?

I'm prob going to go swap the battery now since it's hard to test for current when the battery keeps going dead...

P.S. If I get this truck running I will be signing up for Elite privileges (otherwise I'll be trashing it), this site is an amazing resource!

 

[mikesparky]

A small update: I've ordered a diode (approx $13 for two from the dealer) and was later told by a Ford tech guy that they operate one-way so to check if they're good you check with a meter. You should get flow one way and none the other. I don't have a meter and had ordered them before I discovered this useful info! Eh, whatever. The tech guy also recommended checking the fuel pressure regulator. Anyone know where that is? I'll update after I replace the battery later this evening and check for current at the pump, inertia switch, etc.

 

[mikesparky]

rain delay

Well, it's raining and cold and I'm not in a garage so I won't be doing much today. I am about to pick up the diodes but I'm not holding much hope in them fixing the problem. I hooked up the new battery so I will try to start later tonight and see if the battery or the diodes were the issue.
Ok yeah, if it stops raining I'll check for current and voltage at the pump too.