No Fuel, What Else To Check?

Memphis · Jul 11, 2011

My '94 with 4cyl, 5spd wouldn't start yesterday. Less than a month ago it did this to me and I put a new fuel pump in it. That seemed to fix it, but a day later the fuel pump would come on intermittently. So, I replaced the relay and that seemed to fix it, till yesterday. I did find that I could make a jumper and get the fuel pump to operate, but the truck still would not start. I have not checked the safety switch under the dash just yet, but the last time this happened I checked that and it was fine.
So, what is the next thing to check? What am I missing. This truck has always had a rough idle at first start-up regardless of the weather. Lately that rough idle has lead to it dying and having to be restarted. Fuel pressure regulator? :icon_confused:

Thanks,Scott

TimR · Jul 11, 2011

pressure at fuel rail? when you replaced the pump, did you replace the filter?

Memphis · Jul 11, 2011

I did replace the 'sock' in the tank. The external fuel filter is less than a year old. I know that doesn't always mean anything, though.

killj0y · Jul 11, 2011

Well the fuel filter would be the next cheapest option to replace...

Tonka · Jul 12, 2011

How come you automatically assumed it was a fuel problem? After cranking, are the plugs wet or dry? The only times my 2.9L went into "piece of $h:t mode" (since it was rebuilt) was when I was getting water in the distributor, and another time when I had to replace my fuel tank twice in one month. The second time I shined a light into the tank and found metal shavings, dumped the gas out on some weeds and cleaned them out with a magnet. Not sure how metal shavings got in there, didn't have any enemies at the time, so I left a rare-earth magnet from a computer hard drive between the plastic tank and one of the mounting straps and never had another problem.

Bryan22 · Jul 12, 2011

why didnt you replace the filter? at least pull it off and blow through it. that bad pump could have clogged the shit out of a filter. If you jumped the pump and it was running and you still don't have fuel at the rail, logic says the filter is clogged... I had a bad pump and before i changed it I replaced filters every 500 miles to keep it running. If the sock wasn't put on the pump right, you could end up cloggong filters like I was and eventually losing the pump very quickly.

I personally bought a ford pump. it was expensive, but the sock was allready on it correctly. and i figure pay for the pump once and forget about it, instead of replacing autozone pumps every 2 years.

either way, if you jumped the pump and dont have pressure, it's obviously not an electrical problem. It's either a bad new pump, a clogged filter, or something clogging the lines. Hopefully you get it figured out, I know changing a fuel pump on these is not very fun. Good luck.

Memphis · Jul 13, 2011

Well, I guess I didn't replace the filter because at first, I didn't hear the fuel pump come on so I figured that it must be an electrical issue. Would a dirty filter actually keep the pump from running? That's a new one on me, but you never know. Oh, the truck started right up yesterday. :icon_confused:

Maybe I should open it up again and see if the sock fell off. I'll check the fuel filter, too.
Just wondering what else effects the actual operation of the pump. What else would keep it from turning. What do I check on the Fuel Rail? Thanks,Scott

tomw · Jul 13, 2011

If the pump is coming on intermittently, you have either 1) a loose connection or ground or 2) a relay that is failing. Or 3) an ignition switch that is on the way out.
When you turn the key to ON, the pump should run for 3-5 seconds. If it doesn't, check the relay, the rollover switch and the power at the pump. It will be a 'one-shot' supply of voltage, so you have to be ready to 'read' it.
If you don't get that, check all the above. I'd start at the relay to see if it was being energized, then work my way back, through the rollover at the passengers footwell/firewall, and then to the pump.
tom

Bryan22 · Jul 13, 2011

Memphis said:
Well, I guess I didn't replace the filter because at first, I didn't hear the fuel pump come on so I figured that it must be an electrical issue. Would a dirty filter actually keep the pump from running? That's a new one on me, but you never know. Oh, the truck started right up yesterday. Maybe I should open it up again and see if the sock fell off. I'll check the fuel filter, too.
Just wondering what else effects the actual operation of the pump. What else would keep it from turning. What do I check on the Fuel Rail? Thanks,Scott

I was confused then, I thought you applied voltage directly to the pump bypassing everything and still didn't have pressure. At the fuel rail there is a schrader valve, looks like a tire valve stem. Put a fuel pressure guage on it and check it against the specs in your manual.

Still I'm confused though. You have a new fuel pump, and it's not running unless you jump the relay? Then when you jump the relay the pump is running but the truck won't start? Or is the pump not working at all/ only working when it wants to?

Tonka · Jul 13, 2011

I heard an urban legend once:

Friend of friend of friend of friend times infinity, .. is getting a divorce and he mentions to his friend that she's trying to get his new Mercedes. His friend says "don't worry about it".

The evil woman gets the Mercedes in the divorce, but the car keeps dying on her. Every time it stalls out, it usually starts back up in a few minutes. She has the car looked at by several mechanics who can't find anything wrong with it. But still, the Mercedes keeps stalling out on her but then later it'll fire back up.

Eventually she gets sick of it and gives her ex the Mercedes and says "HERE, I DON'T WANT THIS PIECE OF ****!" and gives the car back.

Dude's talking to his friend about it, and says "well I got the Mercedes back but it's got this problem, it won't stay running and the mechanics can't figure out what's wrong with it"

His friend says "it'll be fine after we drop the gas tank and remove the marbles I put in there".

(Apparently the marbles get stuck in the fuel pump's inlet and starve the gas, but when the key is turned off, and the fuel pump stops trying to suck fuel, the marble falls out and it'll run again, ... until next time.)

I'm 99% sure this ain't your problem. Ain't no way a marble would block the inlet if your pump's anything like mine (I've had mine out before) but it kinda makes you think "out of the box" a little.

Memphis · Jul 14, 2011

The first time this happened around June 16th I went to start the truck and it wouldn't start and I did not hear that faint click and whine from the pump. So, rather than testing many things out, although I did look at the safety switch under the dash, I replaced the pump the next day with one from a reputable parts house. I also put a new sock on. The truck started right up. It was fine for a couple more days and then on Sunday it would not start again. Monday I put a new relay on and that seemed to cure it till this past Sunday. I tried switching relays and that didn't work. I jumped the relay and I could hear the pump whine. Still wouldn't start. This past Monday night when I got home from work I went out and tried it.....it started right up! :icon_confused:

Now, a couple points of interest here: 1. This truck has always acted like a cold blooded vehicle with a bad choke when the engine is cold. Doesn't matter what time of year and lately it has gotten a little worse to where it will die. Then it will restart. 2. I remember now that back in April it did this fuel pump thing to me once. Briefly and then started.
So, new fuel pump, relay, sock. I've not applied voltage directly to the pump just jumped the relay. I'm starting to wonder if the old pump (that I didn't throw away) might be good yet.
Hope this clears things up. Thanks,Scott

Bryan22 · Jul 14, 2011

Sounds like tomw's advice is right on the money then. You could always test the old pump on the bench with a battery, that might shed some more light on what's going on.

Memphis · Jul 20, 2011

I can't seem to get this truck to act up again. Usually that's a good thing, but now I don't know if it's fixed or just waiting to sneak up on me again! I did test the old pump and it works just fine. It must be a wiring connection. I had it running the other day and I went around and jiggled the wiring to see if it would die, but it kept on running.
I was talking to a friend of mine yesterday and he said that it is probably the fuel pump. Even new ones go bad, he says. Something about it not creating enough pressure. He said that I would probably have to buy an actual factory Ford part. I hope not, that would be $430 and the truck might not be worth that now! Can a fuel pump (old or new) work off and on? I would assume not, but......

Bryan22 · Jul 20, 2011

sounds more like a bad wiring going to the relay from what you've described so far.

No Fuel, What Else To Check?

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