Fuel Pump HELP!!!

[johnboy89]

I'm putting a 98 4.6L DOHC in a Mazda Truck and have been trying to get it started.

What appears to be happening is the PCM is not grounding the fuel pump relay so it will turn on.

As soon as I ground the lead the pump will turn on and it will fire.

I flashed the PCM with Sniper and turned off PATS.

Is there something I'm missing???? Looks like the PCM is not turning the pump on for some reason!!!

Thanx

 

[rayner601]

The PCM doesn't ground the relay to turn on the pump. It supplies b+ via the red wire, ckt#361, pin #71 and/or 97 @ the PCM. This doesn't necessarily control the fuel pump, just acts like a switch. The FPDM is what turns the pump off when the engine isn't started within a few seconds. It wouldn't take much to wire that circuit on an oil pressure switch so it isn't running all the time.

 

[billcu]

I believe the PATS can cut the ground to the fuel pump relay.

You said that you disabled the PATS though.

 

[XLRVIII]

I flashed the PCM with Sniper and turned off PATS.
Thanx

I'd start right there.
There have been some reported issues with the PATS disable with Sniper....and SCT has a similar issue with pats...
it either wont disable it, or you get a full time flashing anti theft light.

Need to verify with an 98 mark 8.

Flash it with a stock tune, with pats turned off..and see if a non pats key will start the car.
At worst your out getting a non pats key cut for someone elses car.

 

[XLRVIII]

You said that you disabled the PATS though.

it's a confusing issue with no real answer.

if he were closer to me, he could use my car for a test...but.. it's just a "LITTLE" Far to drive for a test.

 

[XLRVIII]

Hell after second thought..
KK had a problem with PATS when he chromed the ignition switch bezel.
JUST a thin coating of chrome was enough to piss off PATS.

SO... you probably COULD just use a piece of foil with a hole in it, that would tell you if the pats was still enabled, because the pats key wouldn't start the "test mule" with pats enabled.

Then you could turn pats off..and see if the car still starts

 

[johnboy89]

Well I think I might have found the problem. The fuel pump is driven by the FPDM via the PCM. I was trying to drive the fuel pump relay via the PCM

I was told the fuel pump runs at different speeds on the 98's so as the pump is not running at full speed 100% of the time

I was curious what does PATS disable????

I have nothing hooked up via PATS with this truck, it didn't come with PATS.

Here's a link to the build if anybody is interested?

http://www.therangerstation.com/forums/showthread.php?t=42653

 

[jrherald420]

Thats quite an interesting swap youve got going on there.

 

[1bad4.6l]

Awesome build. Now I want to put one in a Maverick.

 

[rayner601]

Well I think I might have found the problem. The fuel pump is driven by the FPDM via the PCM. I was trying to drive the fuel pump relay via the PCM

I was told the fuel pump runs at different speeds on the 98's so as the pump is not running at full speed 100% of the time

I was curious what does PATS disable????

I have nothing hooked up via PATS with this truck, it didn't come with PATS.

Here's a link to the build if anybody is interested?

http://www.therangerstation.com/forums/showthread.php?t=42653

IIRC, with an invalid key, PATS will cut the start circuit. If the start circuit is bypassed and an invalid or no key was detected during the start event, it will run but only for a short time then it cuts the injectors. I don't think it cuts the coils though