hey guys, i searched this and cant find much so here is whats goin on. im a newb by the way. so i was testin the new rad i put in my car, flyin down a counrty road when all of a sudden my car dies! everything electrical works. so i get it towed to my gramps garage and the first thing i checked was the fuel pump. the pump itself works but there is no power going to it. i dont hear it run when i turn the key. iv checked the EGI fuse and the Main Relay but still nothing. what else am i missing here?? iv checked the electrical system with a tester and there is no power until it hits the main relay. but i got a new one on there. any help wouldbe great...sorry this is so long...
Kory

 

ya by the way its a `87 TII and its got a walbro fuel pump but no other fuel mods that would effect anything...all stock in that area

 

Since theres a different fuel pump, the wiring could have gotten messed up. When it was installed, the wiring might not have been done well. I would check where the new wires were spliced in, or whatever. When you splice wires, you should use solder and electrical tape or that shrink-wrap tubing stuff (totally blanking on the name of it). Since you check the fuse and main relay, I would check the wiring between the relay and the pump for breaks, and also check the connections on the relay and on the pump. I don't know the specifics on the wiring of fuel pumps, so I cant give you more detailed instructions. Theres plenty of threads out there regarding the wiring on walbro pumps if you need it.

 

Okay, the fuel pump wont turn on with the key to the "on" position unless the car is running, or the test connector is jumpered. Did you do this?

 

well, the pump will go on with the key but for only a few seconds. check the circuit opening relay under the dash, it's yellow. if that works, check the ground wire under the throttle body. mine did the same thing and the ground bolt was loose. you can see if it's the ground by using the DMM on the yellow fuel pump checker plug. if neither of the terminals are grounded then check that bolt.

 

Umm, no it wont..

 

ok first ill check that circuit and ground, thx fstrnyou. and j-rat ya i had that yellow connector jumpered, sorry forgot to mention that. and if that fails i will check the wiring on the fuel pump itself. thanks alot guys...
Kory

 

Umm, yes it will..

 

Unless the car is running, or the fuel pump check connector is jumpered the fuel pump WILL and SHOULD not run. IF yours does, its bad.

 

Give this man a cookie, because he is correct. It will.

 

Okay, explain how the key set to the on position, car not started, will set the fuel pump to on. Because the Mazda has a safety feature that disables the fuel pump unless 3 conditions are met. One, the car is running. 2, the key is set to "Start" 3, the fuel pump jumper is connected.

This safety feature is there in case of an accident, and the engine dies. It prevents high pressure fuel from being sprayed everywhere.

So please explain. If I am wrong, I would like to know about it.

 

Umm, you're wrong..

No hard feelings. All i figure is that it runs for a few seconds to prime the fuel system. Every fuel injected car i've been in does this.

 

Nope, sorry, just checked it on 2 TIIS fuel pump does not prime

 

You can hear the fuel pump come on for about two seconds when you first turn the key to the on position. This primes (pressurizes) the fuel system so that the injectors are ready to fire when the starter is engaged.

 

You're both right. Some of them will prime, some of them won't prime... its odd. ALL canadian cars will prime, but only some of the US spec cars I have worked on will.

 

Page 4B-7 in the FSM. Then read the pressure testing/priming procedure, same section. FC pumps will not prime when the key is turned to "on". They have no sensing capability to determine if they are at the correct pressure. And they dont "prime" at key on. They use residual pressure

 

well...my car primes when the key is in hte on possition, i am in canada so idunno if that makes a difference like scathcart said. anyways! grounds are fine, no power to the circuit relay under dash. so since there is power goin to the egi fuse and relay its somewhere past that. im really horrible woth eletrical stuff... all i got is a light tester to check stuff right now too, so if i got power to fuse and relay but not to hte relay under my dash (assuming it has something to do with it) then what does that norrow my options down to?? damn being noob sux
Kory