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Fuel pump constantly running

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Old 01-11-16, 04:39 PM
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Fuel pump constantly running

Hey all! In new to the site and I'm about at the end of my rope with this car. I have a 93' FD single turbo. I recently got it back from a shop, it ran great for a few days. Now it keeps flooding out. I had this problem originally about 2 years ago but it had cracked injectors. Now every time I try to start it, it floods out. The plugs a dripping with fuel. I unflood the motor and like all, you have one shot to get it fired before you have to go through it again. I have gotten it running for a min but it sounds like it's getting too much fuel (It runs like you left the choke on). I have noticed something running under the hood as soon as I turn the key on, I felt the fuel supply line and that it what the noise it, the fuel pump is constantly running pushing fuel. I pulled the fuel pump relay and the egi and it still runs. I know the fuel pump should prime the system but could it be stuck injectors causing the pump not to shut off? Is that what its supposed to do? How do I fix this issue? Any help would be greatly appreciated before I smash this thing with a hammer.
Old 01-26-16, 01:48 PM
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Originally Posted by Losack
Hey all! In new to the site and I'm about at the end of my rope with this car. I have a 93' FD single turbo. I recently got it back from a shop, it ran great for a few days. Now it keeps flooding out. I had this problem originally about 2 years ago but it had cracked injectors. Now every time I try to start it, it floods out. The plugs a dripping with fuel. I unflood the motor and like all, you have one shot to get it fired before you have to go through it again. I have gotten it running for a min but it sounds like it's getting too much fuel (It runs like you left the choke on). I have noticed something running under the hood as soon as I turn the key on, I felt the fuel supply line and that it what the noise it, the fuel pump is constantly running pushing fuel. I pulled the fuel pump relay and the egi and it still runs. I know the fuel pump should prime the system but could it be stuck injectors causing the pump not to shut off? Is that what its supposed to do? How do I fix this issue? Any help would be greatly appreciated before I smash this thing with a hammer.
I'm a bit confused to what you're saying, the fuel pump is supposed to always run, that's why there's pressure in the system and excess fuel comes back via return line, I just manually wired my fuel pump with a toggle switch so I can turn it on and off but I leave it on when the cars running, not an expert but is it firing and running? Or just flooding? Also have you fixed the flooding problem with the correct procedure ? Plugs fouled ? Let me know If you still have the problem
Old 01-26-16, 03:23 PM
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Martin S.

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Is the problem related to the worked that was performed by the shop that worked on your car recently? If so take it back to them to fix the issue.
Old 01-26-16, 05:46 PM
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Originally Posted by Mazdav
I'm a bit confused to what you're saying, the fuel pump is supposed to always run, that's why there's pressure in the system and excess fuel comes back via return line, I just manually wired my fuel pump with a toggle switch so I can turn it on and off but I leave it on when the cars running, not an expert but is it firing and running? Or just flooding? Also have you fixed the flooding problem with the correct procedure ? Plugs fouled ? Let me know If you still have the problem
Thanks for taking the time to get back to me. What I'm saying is that the fuel pump doesn't just prime the system it just continues to run even after pulling the pump relay an EGI relay . it ran fine for a bit an now constant flooding. I pull the plugs, pull the relay and EGI relay and crank off and on until the fuel vapor is gone. Then some say to put a bit of tranny fluid in the plug holes to lubricate which I've done, replace plugs and start. I've gotten it running but then when I do it sounds like its getting too much fuel(like you're running a lawnmower with the choke on). It has newer injectors in it only like a year old. I tested the injectors with a 9v battery to make sure the pulse, all of which work fine as far as I can tell. I don't know what else to do. This rotary is whooping me pretty bad, I've built many engines but this thing's got me.
Old 01-26-16, 05:51 PM
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Originally Posted by evo_koa
Is the problem related to the worked that was performed by the shop that worked on your car recently? If so take it back to them to fix the issue.
I wish it were that easy. The shop is in Columbus, OH and I live in Indianapolis, IN and it was the only one here on the east coast that I found to work on RX7s. It's one of those deals to where they sucked and I got my car back with most of the stuff done to it. It ran great but out of no where this all started happening.
Old 01-26-16, 08:00 PM
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Originally Posted by Losack
Thanks for taking the time to get back to me. What I'm saying is that the fuel pump doesn't just prime the system it just continues to run even after pulling the pump relay an EGI relay . it ran fine for a bit an now constant flooding. I pull the plugs, pull the relay and EGI relay and crank off and on until the fuel vapor is gone. Then some say to put a bit of tranny fluid in the plug holes to lubricate which I've done, replace plugs and start. I've gotten it running but then when I do it sounds like its getting too much fuel(like you're running a lawnmower with the choke on). It has newer injectors in it only like a year old. I tested the injectors with a 9v battery to make sure the pulse, all of which work fine as far as I can tell. I don't know what else to do. This rotary is whooping me pretty bad, I've built many engines but this thing's got me.
The fuel pump should always be running, un flood it the right way unlike me who put a new fuel pump in because I took shortcuts to the procedure
1 pull lower plugs
2 cut fuel, pull positive connection off of fuel pump or egi
3crank over for 10 second
4 put a half cup of auto tranny fluid in each rotor housing, is is key to rebuilding compression, don't skip this step...
5 unfoul plugs, I recommend getting new ones.. Reinstall all plugs and wires
Reinstall egi or positive connection, whatever you did to stop the fuel pump, the car should be completely put back together
6put the gas pedal to the floor and start the bitch, going to sound weird at first, please be outdoors, it's going to smoke A LOT, not healthy to breath in, let it run for a bit. I had the same problem as you and it was just flooded and I tried to not do these steps, trust me if you do them it will start right up, and you won't have replaced your fuel pump like me (:

Best of luck to you! Rotarys are a bitch but a beautiful one! Let me know if it doesn't work
Old 01-26-16, 08:07 PM
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I'll give it a shot. I appreciate it. I'll let you know how it goes.
Old 01-27-16, 08:09 AM
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Martin S.

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Banzai Racing is just over 2 hours from you. If you can't get it figured out I would recommend having them look at the car. They have a great reputation and perform great work.
Old 01-27-16, 09:18 AM
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The fuel pump should NOT be running constantly with the key on and the car not running. It should prime and shut off. Sounds like someone rewired the fuel pump incorrectly or they left a jumper at the diagnostics box.

What ECU do you have? Do you have a fuel pressure gauge?
Old 01-27-16, 11:26 AM
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Thanks for replying. I didn't think so either, every other car I've worked on it primes and shuts off. I will have to check out the ECU to see. What should I be looking for to tell which ECU it is? I don't have a fuel pressure gauge. I was hoping someone would know how it was supposed to be wired so I could check it out. Thanks let me know what I'm looking for.
Old 01-27-16, 02:24 PM
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You are single turbo and do not know what ECU you have?

Sounds like you need to make an appointment.
Old 01-30-16, 12:57 PM
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I dont think a fuel pump constantly on would do that, considering its always running when the car is on. Also, i have my pump wired up to constant; it doesn't cause problems like yours. Why dont you check the fuel pressure?
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