if the oil pressure switch is the backup if teh fuel pump relay goes bad

then how do you officially know the relay is bad if the oil pressure switch kicks in automaticallty?

 

Long crank times to start car and no fuel pump prime on ignition on.

 

u say prime on ignition do you mean the noise the pump makes when you turn the key?

and is that long crank times each time or just first time the car hasnt been started in a while?

 

The prime is the noise the pump makes when you turn the key on. With a bad relay, you'd have to crank the car on every start long enough for oil pressure to build up before the fuel pump turned on.

 

yup my fuel pump relay went on me out of the blue one day, def. was one of thing things that just happens.

had to crank and crank about 7 to 8 seconds about 2 times in a row for it to start, I kinda go worried since it was late at night as work and rather not be stranded.

 

lets say u drive for a while shut it off for a few mins would there be enough oil pressure left over to start the car right up no problem or would it need to build up again even if the car was just shut off?

just curious,


thanks for the info guys

 

You only have pressure while the engine is running. Yes, it has to build up again.

 

Just locate your fuel pump relay, and stick a jumper wire to the power lead with the relay still plugged into the connector. Then touch the other end to a good ground, if the relay energizes, or clicks, it's good.

 

Not necessarily.

 

I hope readers already know this, but just to be safe.
There are 2 power leads on the relay. One for the fuel pump, and one for the relay coil.
Depending on which power lead you jumper to a "good ground" you may get:

• Depending on you reaction, a vey hot paper clip
• Burnt fingers
• A blown fuse.
• All of the above.

FYI: The coil is already grounded.

The fuel pump is powered (orange wire at relay) by a Hot At All Times inline fuse near the battery through the relay contacts.
One side of the relay coil (blk/wht wire) is connected to ground.
The other side of the relay coil (grn/wht wire) is powered by the ECM - this is the point that needs to be powerd by 12v. Even if the relay clicks the contacts my not make proper contact to power the pump.

The same can be accomplished with the key off and applying 12v to the "G" terminal (second row, left-side, first pin) of ALDL connector. Assuming the pump, relay coil, and contacts are good you should hear the pump running.

 

Other way around.

the ECM grounds the relay, not powers it.

 

look again. Fuel pump relay:
Terminal "B" goes to engine & ECM system ground pin A12 Blk/Wht wire Circuit 450
Terminal "C" goes to ECM pin A1 Fuel Pump Relay Drive (12v) Dark Grn/Wht wire circuit 465

Diagram could be wrong, but that's how mine works.

 

Interesting. When I ripped apart my old harness to make my new harness, mine was the other way around.

 

First I would like to apologies to Bobby for digressing from his original post. Bobby I hope you find this information of some use.

As long as the relay doesn't have a diode across the coil which, the pump relay doesn't, it won't matter which terminal of the coil is powered. I don't see how the coil would energize with both sides connected to 12v unless there's a potential difference between the two.

The fan relays do have diodes and are switched to ground by the ECM, or the high-temp switch in the passenger side head.

Toe I think we should stop here, or start a new thread on the subject.

 

not a big deal guys, this is weird i noticed that the fuel pump relay is using a fan relay.

or at least the factory number for the fan relay is plugged into where the fuel relay is supposed to be.

the other two relays next to it are correct and our my MAF relays.

car runs fine but i'll replace it with the proper relay anyway