2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Fuel Pump Relay question

Thread Tools
 
Search this Thread
 
Old Dec 8, 2011 | 01:45 PM
  #1  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
MA Fuel Pump Relay question

I need to pickup a new fuel pump relay.
NAPA wants $90. Anyone know where I can get one online?
Reply
Old Dec 8, 2011 | 02:17 PM
  #2  
dwb87's Avatar
This is my social media.
Tenured Member 15 Years
iTrader: (22)
 
Joined: Jan 2006
Posts: 2,744
Likes: 0
From: WA
You could probably get one used in the 2nd Generation Rx-7 (1986-1992) Parts section.

Or...

You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
Reply
Old Dec 8, 2011 | 02:52 PM
  #3  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
Originally Posted by dwb87
You could probably get one used in the 2nd Generation Rx-7 (1986-1992) Parts section.

Or...

You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
I was looking into that day before yesterday. That's probably the way to go-rewire the fuel pump.
Reply
Old Dec 8, 2011 | 03:38 PM
  #4  
rx7_FREAKKK's Avatar
They live We sleep
iTrader: (1)
 
Joined: Feb 2009
Posts: 919
Likes: 0
From: Dot Island
goto the Junkyard? or just buy a genaric relay. they always cost alot when from the store and brand name
Reply
Old Dec 8, 2011 | 07:41 PM
  #5  
HAILERS2's Avatar
Rotary Freak
 
Joined: Jul 2008
Posts: 1,660
Likes: 2
From: FORT WORTH TEXAS
Thread owner.......................are you referring to the relay up front near the radiator or are you referring to the one just above the drivers knees/steering column (the circuit opening relay)?
Reply
Old Dec 8, 2011 | 08:59 PM
  #6  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
Originally Posted by HAILERS2
Thread owner.......................are you referring to the relay up front near the radiator or are you referring to the one just above the drivers knees/steering column (the circuit opening relay)?
The one above the steering column.
Reply
Old Dec 9, 2011 | 10:47 AM
  #7  
HAILERS2's Avatar
Rotary Freak
 
Joined: Jul 2008
Posts: 1,660
Likes: 2
From: FORT WORTH TEXAS
That one is a little peculiar. It has two coils in it either of which can pull the relay in and pass power to the fuel pump (after it passes it to the fuel pump resistor relay up front first).

One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.

The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.

Talking series four car, not series five. Five is slightly different.

Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.

Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.

I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.

Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
Attached Thumbnails Fuel Pump Relay question-twocoils.jpg  
Reply
Old Dec 9, 2011 | 11:02 AM
  #8  
dwb87's Avatar
This is my social media.
Tenured Member 15 Years
iTrader: (22)
 
Joined: Jan 2006
Posts: 2,744
Likes: 0
From: WA
Ah, this is another "I think my fuel pump relay & resistor is my circuit opening relay"... threads. Considering his sig says '88 RX7 TII, I thought he was actually referring to the fuel pump relay & resistor.

freq, you're talking about two different things...
Reply
Old Dec 9, 2011 | 04:09 PM
  #9  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
Please excuse my ignorance, just going by what my mechanic described for me. He called it a fuel pump relay, but I doubt he sees many 2nd gen rx7's thru his shop so... for what that's worth.
Reply
Old Dec 9, 2011 | 04:13 PM
  #10  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
Originally Posted by HAILERS2
That one is a little peculiar. It has two coils in it either of which can pull the relay in and pass power to the fuel pump (after it passes it to the fuel pump resistor relay up front first).

One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.

The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.

Talking series four car, not series five. Five is slightly different.

Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.

Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.

I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.

Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
Hailers, every time I read one of your posts, I wonder how could someone *possibly* know that much about rx7 electrical.
Reply
Old Dec 9, 2011 | 04:50 PM
  #11  
dwb87's Avatar
This is my social media.
Tenured Member 15 Years
iTrader: (22)
 
Joined: Jan 2006
Posts: 2,744
Likes: 0
From: WA
Originally Posted by freq
Please excuse my ignorance, just going by what my mechanic described for me. He called it a fuel pump relay, but I doubt he sees many 2nd gen rx7's thru his shop so... for what that's worth.
I'm not at all calling you ignorant... This is all too common of a problem. If anything, it is the ignorance of your mechanic that I am pointing out. Although he doesn't see very many FC's, you'd think he could at least point you in the right direction when it came to relays. Luckily, you came here.
Reply
Old Dec 9, 2011 | 05:30 PM
  #12  
satch's Avatar
Moderator
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Jun 2005
Posts: 11,738
Likes: 16
From: tulsa,ok.
So what is it about the relay that led you to believe that it is not working properly?
Reply
Old Dec 9, 2011 | 05:42 PM
  #13  
freq's Avatar
Thread Starter
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jan 2006
Posts: 692
Likes: 2
From: North Carolina
After replacing the fuel pump, the car wouldn't start. The mechanic had to pull the cover off the relay, turn the key and then move one of the contacts in the relay in order for the car to start.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
Jul 1, 2023 04:40 PM
Rotospectre
New Member RX-7 Technical
3
Mar 28, 2018 03:33 PM
alphawolff
1st Generation Specific (1979-1985)
17
Nov 17, 2015 05:57 PM




All times are GMT -5. The time now is 06:38 PM.