OK car wont move. Pump, Relay, regulator?

[kitsrider]

Ok, Im sure this has been covered and dont mean to start a new thread but I am reading in circles and not getting a straight answer. A couple weeks back I noticed my 1989 lx 5.0 was starting a little rough. At one point I took the car for a 15min ride shut off, came out of store and I would not start. Turned ignition on and failed to hear pump prime. After cranking car over till batt almost died it finally primed and fired. 1 week goes by with no issues and I jump in my car " no start" , same thing after 5- 10 times finally fires. Im convinced fuel filter is clogged. Put in new fuel filter in and car worked perfect for 1 whole week. Today driving down the highway I felt an abrupt miss as if car just cut out per say. After being parked for 45 min, NO START! NO PRIME! NOTHING! Turns over just fine, reset inertia switch in trunk, swapped out fuel pump relay in parking lot and HAVE plenty of spark. When I turn the ignition to on NO PRIME, but after a few secs hear relay make a click sound .(normal?) Old and new both make the sound. Dont know where to check next? Pressure regulator? Pump shot? I have also read the ignition module in dist. activates pump also? PLEASE HELP!
Thanks!

 

[kitsrider]

Inertia switch has power to both wires. Anyone know where the fuse by starter relay is? Says there is a fuel pump fuse in manual.

 

[kitsrider]

Ok after reading more through here , Ive read if the relay is clicking the problem lies in the wiring to the pump or pump itself. Is there any way I can hot wire the pump to see if it works? Thanks

 

[kitsrider]

Anybody out there?

 

[seijirou]

Ok after reading more through here , Ive read if the relay is clicking the problem lies in the wiring to the pump or pump itself. Is there any way I can hot wire the pump to see if it works? Thanks

Is the relay clicking every time you cycle the key? It should actually click twice, once for the prime, and once again a few seconds later ending the prime.

If so, yes the problem is in the pump or the wiring.

You say you have 12 volts on both sides of the inertia switch, so the wiring is fine all the way to the back. The only thing left is the connector to the fuel pump, and the fuel pump itself.

Pull up the rear carpet and make sure the connector to the pump is good. Make sure the pump's ground wire has a good connection to ground too.

 

[kitsrider]

Thanks for the info. Yes 12v to both inertia switch wires. Relay does click twice. I did not mention that my car is a convertible, Any idea on how to get to those wires on my car without dropping the tank? I am picking up a pump this aft. since auto parts stores will be closed for the next few days. I just found a receipt in my car (no date) in regards to this job being done at some point. Pump,fuel filter, filler seal,tank seal etc. The notes on the receipt quote "pick up harness modify" ????????? Dunno what went on there? If I DO end up swapping out this thing, should I replace any extra seals, gaskets? Do fuel filler seals always get garbaged? Thanks for your help.

 

[seijirou]

Thanks for the info. Yes 12v to both inertia switch wires. Relay does click twice. I did not mention that my car is a convertible, Any idea on how to get to those wires on my car without dropping the tank? I am picking up a pump this aft. since auto parts stores will be closed for the next few days. I just found a receipt in my car (no date) in regards to this job being done at some point. Pump,fuel filter, filler seal,tank seal etc. The notes on the receipt quote "pick up harness modify" ????????? Dunno what went on there? If I DO end up swapping out this thing, should I replace any extra seals, gaskets? Do fuel filler seals always get garbaged? Thanks for your help.

I thought the underbody was basically the same between the hatch and trunk models. The wires go down to the pump through a grommet that is in the spare tire well. I know there's a connector after the grommet. There might be enough slack in the wire to pull the connector up through the grommet hole, it doesn't hurt to try.

Given your symptoms and given that you have 12 volts on both sides of the inertia switch, your issue is most probably a bad ground or a bad pump.

I wish I could give you some good news but I don't think you can do the job right without dropping the tank. You could test for ground at the connector if you can get to it, but that doesn't mean the ground is good further down the wire at the pump.

I know it's a big pain but I would encourage you to drop the tank, make sure you've got good power and ground at the pump, and replace the pump while you're in there.

I've done a few pumps, and I've never had a need to replace any extra gaskets or seals, but give them all a good look and replace whatever needs it.

You have an intermittent problems so do lots and lots of testing before you finalize the installation!!

Also, and this is extremely important, use a brass drift or a block of wood or something to rotate the fuel pump retaining ring. Do not under any circumstances use a screwdriver or anything that can throw a spark. If it means you're stuck and can't do the job for another week because everybody is closed and you can't get a brass drift, wait a week.

I don't want this thread to never get updated again because you blew yourself up.

 

[kitsrider]

Thanks so much! Will do on the wood or brass I dont feel like blowing up this year! Pump will be there in an hour or so. Is there anyway I can hard wire the pump through the plug to see if it works? Or you think my problem lies beyond that point. BTW thanks for quick responses.

 

[seijirou]

Thanks so much! Will do on the wood or brass I dont feel like blowing up this year! Pump will be there in an hour or so. Is there anyway I can hard wire the pump through the plug to see if it works? Or you think my problem lies beyond that point. BTW thanks for quick responses.

Sure it's just 2 wires. Connect the ground and give the other one 12 volts. I don't know the colors off the top of my head, so pay attention to which wire is the 12v wire from the inertia switch down through the harness to the pump.

I don't know what would happen if you wired it up backwards.

Make sure the pickup is in gas. Running the pump dry will burn it up.

Don't forget to run a hose from the outlet to a container somewhere too.

 

[kitsrider]

Unfortunately there are no access holes through my spare compartment, looks like this tank is getting dropped! Happy Holidays and I will keep you posted thanks again!

 

[seijirou]

Cool deal I will keep an eye out.

Good luck!

 

[kitsrider]

UPDATE! So I disconnected the filler neck, drained most of the gas, dropped tank partially. Unplug fuel sending plug (wire brush) same for pump plug. Re-connect turn key to on position and bzzzzzzzzzzzzzz. Fuel pump primes. Unplug complete Y harness near middle of bumper, Inspect plugs , wires , clean and re-tape. Plug it all back in and pump not kicks on 50% of the time but not 100% of the time. WTF?????????? Comments Please and thanks.

 

[seijirou]

Bench test the pump.

By now I'm sure you know which leads on the pump are power and ground. Use some spare wire, and hook the pump up directly to the battery. Make sure it's actually pumping gas through a bucket or something so you don't burn it out.

If it comes on every time you connect it to the battery, you have a problem in your circuit.

Otherwise it'll crap out on you in your hands and you know the pump is bad.

 

[trlprk]

I had a similar problem with my 91 notch, pump wouldn't work half the time, turns out there is a relay in the passergerside kick panel that had gotten moisture in it and was shorting out. pump would shut on and off constantly and kill my battery, and killed the pump. my mechanic found it thank god cause I would have never figured it out. Don't know if it helps, just throwing it out there.

 

[kitsrider]

I guess it would be a bad idea to run some wire to the pump while it is still in the tank? Hot is pink with stripe and ground is black?

 

[kitsrider]

As far as I know the only relay on my 89 is under the driver seat and I started there 1st. New relay, made sure I still had power at inertia switch also . Im thinking this pump is on its way out and only work periodically. Harness "to me" looks fine.

 

[MustangMobster]

I had this same problem in my 84 and when I went to change the fuel pump I found that one of the wires on the pump was off. It started up with the new pump and I'm pretty sure it would have with the old one as well, but I just went ahead and changed it to avoid future issues, but I have a feeling my fuel pump is clogged.

 

[kitsrider]

FIXED! Ended up being a combo of Plug at pump connection. Female O style connectors were stretched out on plug. Even after squeezing them smaller with a pair of needle nose pliers , I couldn't get a good connection. My pump was fine and even had a receipt saying it was done not too long ago. Once I did have the pump out I noticed some brutal solder job on the underside of the hot. Waiting for a new harness now , but until then I drilled out the prongs on pump and hard wired it to existing harness. Wires actually almost fit perfect through holes where prongs used to be, but just for safe measure I siliconed them for moisture and debris entering the tank. Thanks to all who responded! Happy New Year! Curtis.........