Mr357

iTrader: (14)

I've been unable to successfully start my FD for a few days now, and after going through the steps for de-flooding the engine, I realized that the fuel pump doesn't turn on with the ignition, both at the "On" position and when cranking. The EGI fuse and relay both seem to be fine, and the pump definitely starts when I bridge the appropriate pins in the diagnostics port. Can the factory alarm system stop the fuel pump? My FD has a Viper alarm system that the previous owner installed, but I've tried seemingly everything with that.

bpdchief

iTrader: (7)

I don't know how the alarm system is wired (viper) in but if they cut into the fuel pump wiring then yes, it could be your problem. Are you getting voltage at the pump with the key on? If not, you're losing voltage somewhere. You can rewire the pump with a direct wire off the battery to a fuse and then to a relay. There is a write up on here with a diagram as to how to do it.

RotaryEvolution

iTrader: (30)

the factory alarm kills the starter, you might want to see how your viper alarm is wired, that may be what is killing the power to the pump.

OG BBF

2nd this. Aftermarket alarms splice into the starter or the fuel pump. It may not be spliced in the same location but when I bought my car it was spliced in just behind the fuse box....thick white wire with red stripe if my memory doesn't fail me.

Or find your alarm box and trace the wires from there, see where they end up.

Mr357

iTrader: (14)

The funny thing is, I never had this problem the first few times I started it. On the 31st, it cranked twice and then the battery gave out. I charged the battery, had it and the alternator tested, and changed the spark plugs like I had planned to. Still would only crank, so I figured I flooded it the last time it did successfully start. I ran through the steps for that and even tried with WD-40, but no dice. I know the car is low on fuel, but it should still have well over a gallon in it. Is the fuel pump set up to stay off when the car is really low on gas? I'll check the Viper alarm wiring again, but I couldn't find anything that indicated it was connected to the pump.

TravAZ

I was just looking at this thread. It may help you.

https://www.rx7club.com/3rd-generati...-847009/page7/

bpdchief

iTrader: (7)

And once again, are you getting voltage at the fuel pump? You're wasting money and time and getting frustrated when your answer could be found by checking to see if you are getting voltage at the pump. I don't think you are getting voltage at the pump. Second, don't run your car on a gallon of gas. Put more in it. At least a couple of more gallons. Fuel pumps are cooled by the gasoline that surrounds them. When you run the car low on gas constantly, you are shortening the life of your pump. Read the re-wire thread. I haven't had a single problem with fuel delivery since I rewired mine.

OG BBF

The fact that is 'used to' run ok is irrelevant. Problems occur for whatever reason, if they didn't there would never be any issues. You have some good advice on here. If you don't fancy tackling wiring yet just give the pump a direct 12v feed and see if she fires up......atleast this will tell you whether it's the pump or not

Mr357

iTrader: (14)

As I said in the OP, the pump runs if I bridge the pins on the diagnostics port. With the ignition "On" and the port left alone, I am indeed getting voltage at the pump. From the looks of it, the pump hasn't been touched since the car was manufactured, and I can't find any aftermarket wiring that goes to it or the relay. I also checked my spark plugs and they sparked fine, but the threaded ends didn't smell like gasoline. I'll look into doing the re-wire. Thanks everyone.

Mr357

iTrader: (14)

Problem solved as of today, but the culprit was the coolant temperature sensor, not the fuel pump. It only took one try to get it started, but as you can imagine, the exhaust spewed a huge cloud of smoke. I let it warm up and took it out for a nice, long drive. Onto the fun stuff!

RotaryEvolution

iTrader: (30)

losing voltage to the car would set the aftermarket alarm to a triggered/on state, almost making me double down that it is your alarm causing it.

Micheal Rx7

what has the temp sensor has to do with the fuel pump?🤔
As im having exactly the same problem as you had.
pump will only work with ignition on and if I bridge the diagnosis port 🙈

Pump will also pump fuel without been bridged.
but only if engine is turning not befor
and also pump is not to loud you can bearly hear it
you can hear more the fuel on the line going in to the engine
another thing I realised was that there's no fuel returning back out from the engine

And cant get here started
any help would be Apprishiated
thanx

Zbbt

If the fuse is good most likely dead pump. I just had to replace mine because it would come on with key