ok so this is my first post. been lurking on the site reading threads for a while and you guys seem awesome so hopefully you can help me out. my cars a 1991 z32 n/a 5 speed.

it sat for a while cause i was not around but when i got back i threw a new battery in it and it fired right up. ran great for a couple days then while i was driving it it died. it restarted, ran for a little while then died again. now it wont restart. its got spark. got air. not getting fuel. the fuel pump is not running at all. no prime, no nothing. i put a new walbro 255lph and new fuel relay in it and still no go. i got 11v (battery was kinda dead, it was reading 11v too) at the relay and nothing at the fpcu although im not really sure how to test it. i get 1v for 1 second at the fuel pump when i turn the key on. ordered a new/used hopefully working fpcu and it should be here in a couple days. the fpcu looks ok though. its not "blown" looking inside but it is pretty corroded on the outside. i checked all the connecters i could find and couldnt find any loose wires. any thing else i should check? i read about the alarm system causing problems. pretty sure my car has a aftermarket alarm system. could that be the problem? what do you guys think? this is my first z and i love it to death but its no fun when its not running and stuck in the skatepark parking lot.

 

Does the relay click on when you go to key forward? If it doesn't, try grounding out the fuel pump relay and then checking the voltage at the pump.

I had a similar problem where the ECU wouldn't ground the fuel pump relay and I ended up using a relay triggered off the ignition to ground the fuel pump relay.

 

Yea the relay clicks. It clicks twice though. Like on/off. Idk? I just put a new one in so it should be good.

 

Does the voltage spike when it does?

 

At the relay? Not sure. Will test tomarow. But it does jump to 1v at the pump before it falls back to 0v. It was hitting 11v at the pump then dropping to 0v when i first srarted testing things.

 

Maybe a cut cable between relay and pump touching the body ?

 

That could be but i checked and didnt find any. I will look again though.

 

Retested the fpcu. I wasnt testing it right. I had to test as i turned the key on and i got 9v for a second coming from the relay i think cause theres no power coming out of the fpcu or at the pump

 

Did you manually ground the fuel pump relay like I said?

 

nope. which wire do i ground? like which color/wire going into the relay is the ground?

 

i just read about bypassing the fuel pump control module and running it with just a relay. supposedly the fuel pump control module just slows the fuel pump down at idle for noise or something. i don't care about noise....... would it be bad if i did this? would it work? how exactly would i go about doing it? run a positive/negative wires from the relay straight to the fuel pump? i just want my car to run. and not die. i dont know what to do..

 

The one that comes from the ECU, I'm pretty sure it's the black one?

 

It won't solve your problem, that and it will kill the fuel pump faster.

 

ok but will doing it will allow me to make sure it is the controller not working and not something else right. assuming the pump works if i did the bypass.

 

If you aren't getting constant voltage to it, you need to check your relay first.

Ground it out manually like I said and then measure the voltage and see if you can hear the fuel pump.

 

Hoov100, reading the electrical scheme it seems the air regulator (not sure of the technical term) can affects the voltage of the fuel pump... dont know the system enough maybe it's not at any a time of running

 

(EF & EC- 9 documentation)

 

Front what I understand the air regulator is there to bypass air when the engine is cold and is what raises the idle. The fuel pump relay is always triggered when the ignition is on (unless the airbag deploys) and the fuel pump controller always gives the fuel pump 12v and it varies the resistance of the fuel pump ground to determine the speed of the pump.

 

manually grounded the relay. all it did was click like when i turn the key on. didn't make my fuel pump work.

 

bypassed the controller by grounding it out and got the car to start. i guess the means the controller is dead.