lilonghard

We had this 1991 RX7 and we got it to start with a new fuel pump. We had this thing running and we shut it off to finish bolting up the fuel pump and to flush the coolant. When we went to flush the coolant, we used a garden hose and a bunch of things got sprayed a little. After doing that the car didn't start. We have no fuel or spark. The wiring harness is in bad shape so could it be a missing or frayed wire? We are stuck and have been for days, any help would be appreciated.

R_PROWESS

iTrader: (3)

Check the fuses under the hood and inside the car. If a fuse is blown, replace it and try starting the car.

notanymore

the crank angle sensor is where i'd start, and by checking your grounds.

diabolical1

iTrader: (3)

welcome to the board.

if you don't have an FSM, you can get a copy of it from: Foxed.ca

start by checking the fuses under the hood. if the plug is missing from the CAS cover, then definitely pull the cover off and see if water got down inside of it.

notanymore

the EGI fuse controls the ECU power feed as well as the power to the ignition and the injectors. that's the only real fuse in the engine bay that can keep the car from starting. the fuel pump fuse is down by the drivers left foot, 15a but is on a completely separate circuit from anything in the engine bay.

so obviously it's related to what you did in the engine bay, and not with what you did back by the fuel pump.

a simple telltale to whether you have cranking pulses from the engine computer to the ignition coil is the tachometer bouncing while cranking the car over. without the crank angle sensor input you will get nothing, without the EGI fuse you will get nothing, and lastly, with poor grounds you will get nothing. try just twisting the battery terminals to see if they're loose.

i'd be mostly concerned if water got into the crank sensor or crank sensor connector, or if the EGI fuse is blown that you have a direct short to ground on the black/yellow black/white power feeds to various items on the engine harness.

R_PROWESS

iTrader: (3)

The ENGINE fuse in the interior fuse box can also cause a no start.

notanymore

the fuel pump fuse is technically called the "engine" fuse in the interior fuse panel. i have no clue why, it tends to confuse people.

that S1 circuit is fed by the ignition switch, which is fed by the battery. so technically a failing ignition switch can also cause a fuel pump issue. this circuit would not give the symptoms this person gave of a lacking ignition signal, the result would be no fuel to the engine instead.

thank you for reminding me of my mistake in calling the fuse by what i refer to it as, instead of what mazda refers to it as.

R_PROWESS

iTrader: (3)

Oof It's been so long since I've had fuses that I had forgotten this. Years ago I swapped out all OEM electronics for a Racepack PDM now ECU Masters PMU. Good catch.

With that said, I once had the engine fuse blow. I replaced it and it never happened again. Unfortunately I can not recall if it was after a bay wash.