no power to the fuel pump

I have a 95 P/A 130000 miles that has no power going to the fuel pump. I know that the pump only gets power initially for 3-4 seconds and while cranking. I have power to the fuse and relay. I have switched out the relay with one of the same kind. The pump will run if I hot wire it and fuel pressure is reading 62 pounds. I powered it while it is plugged into the factory harness so I assume that the ground is good. The car sat for over a year and I have put about 60 miles on it before the problem arised I also just filled the gas tank immediately before the problem, which I don't think has anything to do with it. I have also tried to start the car with the fuel pump jumped with no luck. I attached a timing light to it while cranking and am getting spark. I really love this car and would like to make it my daily driver again as long as it doesn't cost me an arm and a leg. I am lost :banghead:and need any help you can give. Thanks, ahead of time, Beersnob.

Is this a base PA, or an Ultra?

It's a base P/A.

I have also tried to start the car with the fuel pump jumped with no luck.Are the injectors firing? If you have 60 psig to the rail while jumped & good fire, something is missing!

I planned on checking the injectors in the morning, I'm still stumped about the powerless fuel pump thing and thought that by some slim chance they would be related.

I went to check power to the injectors today using a 194 bulb as a noid light. It showed nothing, so I got my trusty test lamp out just to verify the situation. I'm getting power from BOTH sides of the injector plug. WTF, that cant be correct. I also noticed that the check engine light didn't go one when the key was initially turned on, so I swapped it out with the Traction Control light that has been shining brightly since trying bringing the car back to life, still nothing. I truly believe that my P/A is possessed by gremlins. This is all to strange. My head is starting to hurt from all this wackiness.:banghead:

Gremlins tend to hang around in the PCM on the 94-95 transitional years to OBDII. This may or not be the case here, but the 95 PCM is prone to failure. When the PCM takes a dump, all sorts of strange things happen!

That's not very encouraging. The car doesn't owe me anything, It has given me many years of faithful service, but I still think she has a few years left in her, The body and int are in really good shape for her age. I'd really hate to scrape her. Can you swap out the pcm with a used one or does it have to be new or programmed? I parked this car for the use of my mom's Camry, which she can no longer drive thanks to Alzheimer. There is no comparison between the P/A and The Toyo except a couple mpg's. I should have parked the Toyo. Damn It!

If you want to try the PCM, it is not that difficult to get one from a JY, (35-50 bucks) or a rebuilt one from one of the parts stores such as O'Reilly for less than 100-bucks with a lifetime warranty. Simply remove the existing PCM from under the passenger side dash and remove the screw(s) from the small cover on the back and remove the prom and install in the replacement. The info shown below will help you identify what you need. No programming required!

#16183247 LeSabre '94-95 Elec Cont Module (ECM); (6-231, 3.8L)

Application:
1994-95 3.8 V6 SFI “L” L27
1995 3.8 V6 SFI “K” L36
1994-95 3.8 V6 SFI supercharged “1” L67
1994-95 truck 3.8 V6 SFI “L” L27

MEMCAL IDs: “L”: BMYU, … “1”: …“K”: … EPROM type: 27C512


(http://www.cruzers.com/%7Eludis/p4pinouts.html#16067633)

I really hate to throw parts in to it if I'm not sure what is the problem. Anyone else have any other suggestions or opinions on this. I'm going nuts trying to figure it out.

I just replaced the PCM with a used one out of a running 95 Riveria, still the same. Does the PCM have a relay that I should be checking? HELP!

I have the same problem. A few others too I think. I bypassed the VATS system and now use a blank key so I know its bypassed because the car cranks over. But still no power to the fuel pump. Replaced it yesterday just to eliminate that. Im seeing alot on the PCM. Will the PCM keep power from the fuel pump? Also, I hear there is a safety shut off relay for this car too. If the car should tip too far or roll the pump cuts off and you can reset it by disconnecting the battery for 5 min. Need a super pro to figure this thing out....

Vats has nothing to do with the fuel pump power supply, nor is there any "safety shut off" device. Shown below are the typical schematics for VIN-1 & VIN-K circuits. Notice the 96-98 Vin-1 uses a speed control module similar the auto climate control blower fan module.

http://img527.imageshack.us/img527/918/buickfuelpumpvinkvin1fu6.gif

There is no shut off for the pump. You need a good wiring diagram to properly trace this, no guess work. Start at the fuses and work from there with a diagram. Try autozone.com repair guides for a basic one.

Autozone.com dont have any info on this car. There are 6 relays on the firewall but none are marked so im not sure which one it is. Still the issue of the pcm. Sounds like it can only be the pcm or the relay. The problem is that the car is a friends and I drive 60 miles to work on the car.. Maybe I can get someone to help out with a short call.. any help is great. 8165894239

Thanks

The fuel pump relay is located in the fuse/relay panel under passenger side dash.

I spent the morning swithching like kind relays under the hood with no luck. I don't know if I should be chasing the fuel pump problem or the not starting problem first, (which seems to be a power to the injector problem) are they assosiated with each other. The car cranks so the VATs is not the problem and GM cars don't use an inertia fuel shut-off switch. I can get fuel to the rail by hot wiring the pump and I have spark so I know it's not there. Is there anywhere on the web that I might find all the schmatics for this car so I can start chasing this gremlin.:evillol::evillol:

I spent the morning swithching like kind relays under the hood with no luck.Once again, the FP relay is under the passenger side dash, not under the hood. Have you checked the FP fuse? In addition, the fuse is in the same location.

If you read my origanal post you would know that all that has been checked. Please re read so that you know were I'm at with this mystery. I was checking the relays under the hood to see if anyone of them would affect the PCM. I have 12 v. at both wires that go to my injectors? That is my biggest concern right now. Aren't the injectors grounded through the PCM? I really need a schmatic for the thing. Or someone who is up for a challenge to think about what to check next.

You should not have power on both sides of the injectors, I would focus, for now, on that issue.

Only the pink wire to the injectors should have power & yes, the PCM should pulse the ground on the other wire, provided that the TDM is sending the PWM signal to the PCM do do it's thing. Check your PM message.

could be a safty issue, like if it looses oil pressure it will shut down the fuel pump or the ignition module to kill the engine to pervent any damage

TDM, PWM? I'm an old bodyman, whats that mean?

I replaced the oil sending unit after check pressure with manual gauge ( Origanal sending unit was showing low pressure. )

could be a safty issue, like if it looses oil pressure it will shut down the fuel pump or the ignition module to kill the engine to pervent any damage Theft Deterrent Module = (TDM-VATS) Pulse Width Modulated = PWM (pulsing signal)

On this particular model Buick, the oil pressure sender is simply a variable resistor that controls the gauge. If you don’t have a gage, then there are a set of N/C contacts that are used to turn on the light with low pressure.

In addition, there are another set of contacts in the sensor that are N/O and close when the oil pressure reaches 4 psi. This is a bypass circuit used to supply a second source of power to the fuel pump in the event of a FP relay failure.

My wife's old 94 Le Sabre had a problem with the VATS, and it affected the cranking not the fuel or ignition. I bypassed it with an inline resistor, rather repairing it. Is the 95 P?A different?

The VATS system performs two functions related to starting. First is it activates the start enable relay that provides power to the purple wire going to the starter solenoid. Next, it sends the PWM signal to pulse the injectors. Some may use a BCM instead of TDM for these functions. The 94-95 are basically the same, using the same PCM and VATS system.

I'll be out checking everything out tomorrow, It's been rainning here all day. Thanks for all the info you have provided so far.

Smae problem for me still too. I ran a code tester and got 1 code that was the tps. I know that wont stop the fuel pump but I replaced it anyway. Bought a new FP relay still no fuel to the pump. It cant be a fuse because the problem is intermittent. For anyone else reading this post, The FP relay is a pain to get to. Pull the glove box down all the way and look on the right side. There are 3 large relays (1.5 in. square) and 3 or 4 below that (.5" by 1.5") there is 1 single (small) relay by its self beside all the others. That single relay is the FP relay.
At this poing all I can think of is the PCM which I understand can come from a salvage yard and dont need flashed. New is 100 bucks. Kinda expensive for a hope that it is the problem..Does anyone know if the ignition module can cut power to the FP?

PM me with an email address if you still want a wiring diagram.

There should be a lead by the battery that you can use to send +12 volts to the fuel pump. If the pump still doesn't run then you should check the driver's side ground bus for corrosion.

If you have fuel pressure & the engine still doesn't start:
Check for spark at each of the three front cylinders.
Check for fuel injector pulse.
Try starting with the MAF sensor unplugged.

It cant be a fuse because the problem is intermittent.

I have seen intermittent problems due to oxidated fuse contacts. To rule out this possibility carefully clean them with a sandpaper nail file.