2nd Gen General Discussion The place for non-technical discussion about 2nd Gen RX-7s or if there's no better place for your topic

Should the fuel pump always run with the key to the "on" position?

Thread Tools
 
Search this Thread
 
Old Nov 18, 2019 | 04:53 PM
  #1  
MountainTurbo's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
 
Joined: Jan 2004
Posts: 515
Likes: 0
From: Utah (land of mountains)
Should the fuel pump always run with the key to the "on" position?

87TII. I was under the impression that to get the fuel pump to run without the car running you need to jumper the test connector and then turn the key to "on", however in my car if I turn the key to the on position the pump runs constantly, no jumpered test connection. Is that normal?
Reply
Old Nov 18, 2019 | 05:20 PM
  #2  
DC5Daniel's Avatar
Rotary Freak
Tenured Member 10 Years
iTrader: (10)
 
Joined: Jul 2012
Posts: 1,631
Likes: 89
From: Peachtree City, GA
No that's not normal.

I posted some data in another thread on an issue which can cause this to happen. Do you happen to have a relay added to your starter solenoid circuit?

There are two things that turn the fuel pump on: the AFM when the car is running, and the starter signal.
Reply
Old Nov 18, 2019 | 05:31 PM
  #3  
MountainTurbo's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
 
Joined: Jan 2004
Posts: 515
Likes: 0
From: Utah (land of mountains)
Yeah see that's what I thought! The car is completely stock as far as I know with 50k miles on it(well it has an unknown catback and a short throw shifter). I opened up the hatch over the fuel pump and the wiring is all original still. It still has all the emissions stuff etc as well.

Originally Posted by DC5Daniel
No that's not normal.

I posted some data in another thread on an issue which can cause this to happen. Do you happen to have a relay added to your starter solenoid circuit?

There are two things that turn the fuel pump on: the AFM when the car is running, and the starter signal.
Reply
Old Nov 18, 2019 | 05:54 PM
  #4  
MountainTurbo's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
 
Joined: Jan 2004
Posts: 515
Likes: 0
From: Utah (land of mountains)
Also the fuel running through the rails is LOUD, and almost hisses. Like maybe I have a stuck injector? Or does it sound normal?

Reply
Old Nov 19, 2019 | 07:14 AM
  #5  
DC5Daniel's Avatar
Rotary Freak
Tenured Member 10 Years
iTrader: (10)
 
Joined: Jul 2012
Posts: 1,631
Likes: 89
From: Peachtree City, GA
Originally Posted by MountainTurbo
Also the fuel running through the rails is LOUD, and almost hisses. Like maybe I have a stuck injector? Or does it sound normal?

I can't comment, I haven't had a stock car in 8 years

As per your original issue, I would start at the easiest place, which is the circuit opening relay under the steering column. In case you don't have the FSM, I have linked a thread that explains the circuits and shows the diagram excerpts.

If you determine the ouput of this relay is stuck on with key to ON but not running, then one of the two coils are engaged and go from there. If the output is behaving as expected I would move to the fuel pump resistor/relay by the driver's side rear strut tower.

Let us know what you figure out.

https://www.rx7club.com/2nd-generati...y-fail-875397/
Reply
Old Nov 19, 2019 | 03:06 PM
  #6  
MountainTurbo's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
 
Joined: Jan 2004
Posts: 515
Likes: 0
From: Utah (land of mountains)
Well I think I at least have a start. I unplugged the MAF and the pump shut off, so when I get a second I'm going to pull the MAF out and see if the door is stuck open or if something shorted out in it. Hopefully that's an easy fix, if not I might be going Adaptronic sooner than I planned. haha
Originally Posted by DC5Daniel
I can't comment, I haven't had a stock car in 8 years

As per your original issue, I would start at the easiest place, which is the circuit opening relay under the steering column. In case you don't have the FSM, I have linked a thread that explains the circuits and shows the diagram excerpts.

If you determine the ouput of this relay is stuck on with key to ON but not running, then one of the two coils are engaged and go from there. If the output is behaving as expected I would move to the fuel pump resistor/relay by the driver's side rear strut tower.

Let us know what you figure out.

https://www.rx7club.com/2nd-generati...y-fail-875397/
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cumberlandrx7
2nd Generation Specific (1986-1992)
21
Sep 18, 2009 01:16 PM
turnski
2nd Generation Specific (1986-1992)
6
Aug 16, 2009 08:41 PM
MIDWESTSTYLE
New Member RX-7 Technical
5
Jan 27, 2009 04:38 PM
murgocurgo87
2nd Generation Specific (1986-1992)
8
Jul 21, 2008 03:45 PM
87na33
2nd Generation Specific (1986-1992)
2
Jan 11, 2008 01:29 PM




All times are GMT -5. The time now is 10:59 AM.