Cranks but no spark. Insuficient power to the fuel

OK it is definately a power or ground issue... Unfortunatly I cannot tell you exactly where to start checking untill tomorrow around 6 pm central time. We use a program called Alldata where I work that has all factory service manuals for most all makes and models of car/truck back to 1982 on computer. Again im not sure if it has a CCRM as I mentioned earlier, your 94 tarus does though, im positive of that. The CCRM is basicall just a bunch of intergrated relays in one box, and the contacts get corroded in the relays just like any normal relay. The CCRM on your taurus is located on top of the radiator fans, just the drivers side under the hood. It is usually under a black piece of plastic which has the underhood engine sticker and some other stickers on top of the upper radiator support. The CCRM looks like the pcm, only a little smaller. Locate the CCRM on your tarus if you can and try and see if you can find something that looks like that on your tour... beating the hell out of the CCRM sometimes knocks the relay contacts around enough that the car might start. You will here the fuel pump run, the CEL will come on, and maybe a warning chime will sound letting you know you were successful. Since you say the fuel pump has low voltage, I'm almost positive this is the problem, as the same relay that powers the pcm ALSO powers the relay for the feul pump.

Thank you,

If you notice in my first post I did replace my fuel filter and even though I didn't say it, I did put some HEAT in my tank. Not much moisture in SoCal to accumulate in a gas tank, but I thought, what the hell? Still, no joy.

Welcome. Change the fuel filter. Put HEET in gas tank (or gas stabilizer). Then check if the starter is "shot".

Changing the fuel filter (while it is a good idea and should be changed anyway) most definatly will not solve your problem.

A dirty fuel filter will not cause the vehicle to lose spark. If the CEL does not light as a bulb check when the key is first turned to the 'run' position, the PCM DOES NOT have power. Unless, of course, the bulb is burnt out, or that particular circuit is bad in the PCM - but those are highly unlikely.

Originally posted by crappywheelhop:
OK it is definately a power or ground issue... Unfortunatly I cannot tell you exactly where to start checking untill tomorrow around 6 pm central time. We use a program called Alldata where I work that has all factory service manuals for most all makes and models of car/truck back to 1982 on computer. Again im not sure if it has a CCRM as I mentioned earlier, your 94 tarus does though, im positive of that. The CCRM is basicall just a bunch of intergrated relays in one box, and the contacts get corroded in the relays just like any normal relay. The CCRM on your taurus is located on top of the radiator fans, just the drivers side under the hood. It is usually under a black piece of plastic which has the underhood engine sticker and some other stickers on top of the upper radiator support. The CCRM looks like the pcm, only a little smaller. Locate the CCRM on your tarus if you can and try and see if you can find something that looks like that on your tour... beating the hell out of the CCRM sometimes knocks the relay contacts around enough that the car might start. You will here the fuel pump run, the CEL will come on, and maybe a warning chime will sound letting you know you were successful. Since you say the fuel pump has low voltage, I'm almost positive this is the problem, as the same relay that powers the pcm ALSO powers the relay for the feul pump.

Thank you, I will look into that right away. I can't use the Taurus as a reference since it died 150 miles away from home with my wife and two kids in it

Hopefully I will be able to find it and get things running again before tomorrow, but if I don't I'll be waiting to hear what you have to say.

Thanks,
Jason

Originally posted by zbgebe:
If you notice in my first post I did replace my fuel filter and even though I didn't say it, I did put some HEAT in my tank.

It appeared that you changed your fuel filter before your pump. Sediment might have got stirred up again. And if you haven't changed the air filter, might as well do it.

Originally posted by Tony2005:

Originally posted by zbgebe:
If you notice in my first post I did replace my fuel filter and even though I didn't say it, I did put some HEAT in my tank.

It appeared that you changed your fuel filter before your pump. Sediment might have got stirred up again. And if you haven't changed the air filter, might as well do it.

If there was enough sediment in your tank to cause instant clogging of the fuel filter... throw the tank away and buy a new tank. Normal driving of a vehicle 'stirs up' any thing that might be in the tank.

Originally posted by crappywheelhop:
If there was enough sediment in your tank to cause instant clogging of the fuel filter... throw the tank away and buy a new tank.

$400 for a new tank and $400 to install!

I would change the fuel filter and then not stir up the sediment again (or not let gas go below 1/8 tank) any day.

Originally posted by Tony2005:

Originally posted by crappywheelhop:
If there was enough sediment in your tank to cause instant clogging of the fuel filter... throw the tank away and buy a new tank.

$400 for a new tank and $400 to install!

I would change the fuel filter and then not stir up the sediment again (or not let gas go below 1/8 tank) any day.

LMAO OK, sorry I was joking... seroiusly though, thats not even an issue. If the feul tank was THAT contaminated, this guy would need a whole new fuel system. I guess one would probably want to just CLEAN the tank before they bought a new one, and I don't usually factor in the cost to install anything as I am an auto tech, and I'll be damned if anybody else touches my car, but thats not an issue either. I was just trying to emphasize that there is no way I know of that a clogged fuel filter could cause a car to lose spark...

Originally posted by crappywheelhop:

LMAO OK, sorry I was joking... seroiusly though, thats not even an issue. ..... I was just trying to emphasize that there is no way I know of that a clogged fuel filter could cause a car to lose spark...

LOL. Crappy, you're ok, I don't care what the others say about you, but you're ok.

But I wasn't suggesting that a clogged filter was making the car lose spark. It could be sputtering due to lack of fuel due to a clogged filter (or air filter).

You're from socal, come and post in the cali boards. We have a couple mechanics and some pretty smart guys that might be able to help you out (some rarely check outside of the cali forums). hope you get everything solved!

Originally posted by Tony2005:

Originally posted by crappywheelhop:

LMAO OK, sorry I was joking... seroiusly though, thats not even an issue. ..... I was just trying to emphasize that there is no way I know of that a clogged fuel filter could cause a car to lose spark...

LOL. Crappy, you're ok, I don't care what the others say about you, but you're ok.

But I wasn't suggesting that a clogged filter was making the car lose spark. It could be sputtering due to lack of fuel due to a clogged filter (or air filter).

Tony,

I wish that was the problem right now. It would be a whole lot easier than what it seems to be. Unfortunately, there is no sputering, It cranks but won't start. In fact, there isn't even a signal from the PCM to the FP relay. And, there is something else going on as just shorting the relay and leaving the pump on all the time doesn't fix the problem (at least it still won't start). BTW, the tank is a little over half full and when I siphoned it out, it was as clean as a whistle.

Jason

OK, I printed the wiring diagram for your pcm out, looked at it BRIEFLY, then forgot to take it home when i left, cause im a dumbass... sadness.

It does not have a little integrated relay box thingy like your taurus, all the relays should be in your underhood fuse box... I probably should have deciphered that from your posts, seeing as you said you jumpered the fuel pump relay... but anyways.

I just looked at my underhood fuse box... and then just remembered Ford doesnt label the fuses or relays... bastards. I'm guessing you have a book telling you whats what as far as relays go, pull the pcm power relay (hopefully thats what they call it...) and jumper that relay. If that doesnt work, make sure you have 12 volts on at least one pin there. It is better to check it with a high amerage test light (by high ampereage i mean like 2 amps) than a multimeter, because faulty connections will test good with a multimeter if there is no current flow through them. If the power is good there, follow all the ground wires you can see as far as you can checking for any signs of split wires and green corrosion at the connectors. If I had actually remembered to grab the stuff i printed out, i could tell you what wires to check and where they are, as well as where the grounds connect to the body. Of course if everything is there, power, grounds cam/crank and so on, the pcm has to be the problem.

Since you have no CEL with key in the run position the pcm is NOT powering up, so it is missing either the main key on power, or it has a corroded grond connection. If you have a haynes or chilton it should have some wiring diagrams in it. On the diagram, the wires going into the box labeled 'pcm' should all have a number where they go into the box, those numbers should be the pin numbers in the pcm main plug. The pins on plug on the car are also numbered. IF you are lucky enough to have all this info and savy enough with your multimeter, you should be able to check the power and grounds at the pcm plug by 'backprobing' where the wires go into the plug with a sewing t-pin. You do not have to disconnect anything to this, and its beter not to, if you have the room to work... DO NOT pierce the wire insulation!!

I wish I would have remembered those diagrams, because to me this is a simple problem, IF you all the information that is lol

Sorry this is probably confusing as hell, but I never was good at explaing things to anybody.

ACK I fire myself...

Originally posted by crappywheelhop:
OK, I printed the wiring diagram for your pcm out, looked at it BRIEFLY, then forgot to take it home when i left, cause im a dumbass... sadness.
......
I wish I would have remembered those diagrams, because to me this is a simple problem, IF you all the information that is lol

Sorry this is probably confusing as hell, but I never was good at explaing things to anybody.

ACK I fire myself...

LOL. Crappy, if I were Zbgebe, I wouldn't know whether to laugh or cry. LOL.

Originally posted by Tony2005:

LOL. Crappy, if I were Zbgebe, I wouldn't know whether to laugh or cry. LOL.

LMAO yeah I sucked on this one... I WILL DO BETTER NEXT TIME Zbgebe! lol

Originally posted by zbgebe:

Originally posted by Tony2005:

Originally posted by crappywheelhop:

LMAO OK, sorry I was joking... seroiusly though, thats not even an issue. ..... I was just trying to emphasize that there is no way I know of that a clogged fuel filter could cause a car to lose spark...

LOL. Crappy, you're ok, I don't care what the others say about you, but you're ok.

But I wasn't suggesting that a clogged filter was making the car lose spark. It could be sputtering due to lack of fuel due to a clogged filter (or air filter).

Tony,

I wish that was the problem right now. It would be a whole lot easier than what it seems to be. Unfortunately, there is no sputering, It cranks but won't start. In fact, there isn't even a signal from the PCM to the FP relay. And, there is something else going on as just shorting the relay and leaving the pump on all the time doesn't fix the problem (at least it still won't start). BTW, the tank is a little over half full and when I siphoned it out, it was as clean as a whistle.

Jason

Jason, crappywheelhop has you on the right track (as he should being an ASE tech). Have you looked in to your ignition relay? It is located in the under dash fuse box. It's the yellow one. I've had a number of them with the same no start symptom as you're describing and the igintion relay was the issue with all of them. Not saying it's your issue for sure, but it's easy to check.

If that relay has malfunctioned the pcm will not receive a signal. Therefore it will not power the pump relay or provide any spark. The car will still crank over just fine, but with out the pcm receiving the ignition signal it will never start.

If you're still dead in the water, here is some more info; all the relays get their power diectly from the battery, which is about 3 inches away from the fuse box, so thats not hard to chase down. the main computer ground should be mounted to the stupid little grounding plate on the negative battery post, or mounted to the body underneath the battery - remove the battery and it should actually be mounted to the frame the battery sits on... that would be the most likely place for a problem. 2 other grounds to check are below the left headlight (in the engine compartment, don't remove the headlight...) and directly behind the right headlight. BOTH the power and gounds go through connector c100 on their way to the computer. The pcm should be set in the upper right hand side of the firewall. Connector c100 should be between the airbox and left strut tower, its the big white flat one. This connector is the least likly place for a problem, because the power and ground both split so they use 2 pins each in the connector to help distrubute the current.

Your best bets are the relay mentioned by Figols, or the individual grounds at the negative battery post and under the battery itself. Under the batery is quite possibly the worst place I could think of for a ground, because the simple fact I have never seen an 'underneath of a battery' that wasn't corroded to all hell on any vehicle. On some cars its the only place with any corrosion...

If you find the computer is getting the proper supplies and grounds, then you must condemn it as the faulty part.