Ford Racing harness low voltage fuel pump - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Ford Racing harness low voltage fuel pump

15 x 8 Black D-Window Steel Wheels Set of 4ZONE 4.25" combo lift for TJ available at Rockridge4wROCKRIDGE4WD Introduces a NEW Jeep Wrangler JK *led* tail

Reply
Unread 08-16-2014, 08:02 AM   #1
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
Ford Racing harness low voltage fuel pump

I know this is the CJ section but I think this still applies to you guys.

I've tried searching everywhere for this and I can't seem to find an answer. If anyone has a link to the thread if this has already been discussed I would really appreciate it.

I'm in the process of putting a 5.0 in my 90 YJ. I'm using the ford racing harness. I thought it would simplify things. I have a brand new fuel pump and if I hook it up straight to the batter it turns on fine.

The problem is the fuel pump lead wire that comes from the FRCM. It's only ever giving me 7 volts, its not enough to power the relay switch or fuel pump. I'm not sure if its just a ground issue or what. All the other relays seem to come on fine and I can crank the engine no problem. The green LED indicator lights on the FRCM are lit up too. The manual says to use the lead wire as the switch wire on the relay which I've done. I know it's only active for the first few seconds when you turn the ignition to ON position. I never get the 12v I need to flip the relay or power the pump. Hoping its not a bad ECU (A9P) or something.

If anyone has had similar problems and can help me out I'd appreciate it. I'll be posting on the ford forums to, maybe someone there can help me.

Just some more details. For the 8 pin FRCM connector I have the following connections:

Pin 1 and 2 are hooked up to a check engine light (My YJ doesn't have one so I'm using a small indicator light from the auto store, light does flash when you first turn ignition to on position)
Pin 3 is a Red/Blue wire which needs to be connected to a START wire. I hooked this one up with the wire used to initiate the starter (crank wire).
Pin 4 Is a ground wire (body) I placed this with the fuel pump ground by the emergency brake assemply
Pin 5 Fuel pump lead (+) Hooked up to switch side of relay. (This is the line only giving my 7 volts, can't flip the relay)
Pin 6 A/C control switch (Not hooked up)
Pin 7 12V start and Run, hooked up to Ignition switch (YL) wire on engine bay bulkhead
Pin 8 Tach lead, not hooked up yet (waiting on gauges).

jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 09:19 AM   #2
HackFabrication
Registered User
1976 CJ5 
 
Join Date: Nov 2007
Location: Canton, Michigan
Posts: 2,548
According to this you have it wired wrong: http://www.jegs.com/InstallationInst...-12071-A50.pdf Page 10

There is no Pin 5
Pin 6 is for the positive side of the fuel pump or used to trigger a relay for the fuel pump
Pin 7 is for the A/C
Pin 8 is for single source 'start' and 'run' 12 volts
Pin 9 is for a tach

I would run Pin 4 directly to the battery negative post.
__________________
"In the end...It's all Hack."
HackFabrication is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 09:27 AM   #3
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
Quote:
Originally Posted by HackFabrication View Post
According to this you have it wired wrong: http://www.jegs.com/InstallationInst...-12071-A50.pdf Page 10

There is no Pin 5
Pin 6 is for the positive side of the fuel pump or used to trigger a relay for the fuel pump
Pin 7 is for the A/C
Pin 8 is for single source 'start' and 'run' 12 volts
Pin 9 is for a tach

I would run Pin 4 directly to the battery negative post.
Ok thank you I'll try run the ground to the battery. I know the manual on JEGS is saying there's no Pin 5 but I either have a newer version of the harness or an older one because the harness I have looks different than the one on JEGS. Either way though its the same concept. Has the same wires and it still needs to be wired correctly. My manual just goes 1-8 and has a Pin 5.
jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 10:37 AM   #4
HackFabrication
Registered User
1976 CJ5 
 
Join Date: Nov 2007
Location: Canton, Michigan
Posts: 2,548
Quote:
Originally Posted by jovanbiljon View Post
...I either have a newer version of the harness or an older one because the harness I have looks different than the one on JEGS. My manual just goes 1-8 and has a Pin 5.
Then I would call Ford Racing and ask them.
__________________
"In the end...It's all Hack."
HackFabrication is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 11:01 AM   #5
Dngrs1
Registered User
1979 CJ7 
 
Join Date: May 2009
Location: Mohave Valley,AZ
Posts: 804
Quote:
Originally Posted by jovanbiljon View Post
I know this is the CJ section but I think this still applies to you guys.
How does this apply to CJ's?
__________________
I would rather have a tool I don't need, than need a tool I don't have.
Dngrs1 is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 11:07 AM   #6
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
Quote:
Originally Posted by Dngrs1 View Post
How does this apply to CJ's?
Because CJ's do the exact same swap too? The issue is specific to the racing harness, not really anything to do with the YJ it's self.
jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 12:01 PM   #7
Jim1611
Web Wheeler
 
Jim1611's Avatar
1985 CJ7 
 
Join Date: Jul 2009
Posts: 5,655
Quote:
Originally Posted by Dngrs1 View Post
How does this apply to CJ's?
I saw his thread earlier on the YJ section and sent him a pm suggesting he post it here on our CJ section. He was invited and since many of us are doing or are in the process of doing the Ford 5.0 swap I figured he'd get some help here, which he is. I'm sure he'll get some more after some of the other Ford guys see the thread. Who knows you may want to do the swap yourself and what he finds out may help you
__________________
www.crabtreetool.com (Crabtree Shackle Hangers)

My build thread
http://www.jeepforum.com/forum/f8/ji...build-1093702/
Jim1611 is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 06:53 PM   #8
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
I tried hooking up the ground straight to the battery, still only getting 7 volts =/
jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 10:06 PM   #9
HackFabrication
Registered User
1976 CJ5 
 
Join Date: Nov 2007
Location: Canton, Michigan
Posts: 2,548
How is the main power to the harness hooked up? Mine is directly connected to the positive battery terminal.
__________________
"In the end...It's all Hack."
HackFabrication is offline   Reply With Quote Quick reply to this message
Unread 08-16-2014, 10:41 PM   #10
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
Ok I have an update. My main power is directly to the battery too. If I jumper ground connection from the self test connector (test connector) to the ground post on the relay, then splice the fuel pump monitor wire with the 12v out source to the fuel pump, and have the constant 12v source from the battery on the constant post, and a 12v ON source on the switch post it functions properly. Relay is triggered for a second or two when you turn the ignition, then it stays on when I turn to the on position.

The ground wire wire goes from the PCM out to the self test connector. The 7v fuel monitor wire goes from the PCM to that 8 pin connector. Here is a diagram of how the relay is wired now. The ford racing manual I have lists these wires under the PCM pin layout. It even says this is where the wires go. I'm not sure what a correct way to wire this would be now? Jumpering the wire doesn't seem like the best thing to do.

Now I'm trying to get the engine to run. Fuel rail has good pressure. Sitting right at about 39 psi. Seems to have spark, It ran off the starter spray for a bit. Lol one problem after another.
fuelrelay.jpg

jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-17-2014, 07:05 AM   #11
HackFabrication
Registered User
1976 CJ5 
 
Join Date: Nov 2007
Location: Canton, Michigan
Posts: 2,548
Do you have an internet link for the instructions that you are using? If your harness differs from the one I posted, then I will need to look at yours. Appears that FRP updated their harness to eliminate the EVAP, EGR, CANP from the earlier version.

I used an aftermarket harness (RJM), and had no problems. Send me a PM with your email address. I'll want to see some pictures.
__________________
"In the end...It's all Hack."
HackFabrication is offline   Reply With Quote Quick reply to this message
Unread 08-17-2014, 10:48 AM   #12
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
Hack I sent you a PM, thanks for the help.

Just another update, after some trouble shooting I think I found the next problem. Fuel injectors are only getting 7v when engine is cranking. So they won't open up. I'm about to throw this harness in the trash. A little frustrating, seems like the ECU can't make the correct grounds for anything.
jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-17-2014, 01:38 PM   #13
HackFabrication
Registered User
1976 CJ5 
 
Join Date: Nov 2007
Location: Canton, Michigan
Posts: 2,548
what ECU are you using? What's the year of the 5.0L and what did it come out of?
__________________
"In the end...It's all Hack."
HackFabrication is offline   Reply With Quote Quick reply to this message
Unread 08-17-2014, 02:11 PM   #14
jovanbiljon
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: orem, Utah
Posts: 40
I'm using the A9P ECU. The engine is from a 97 explorer. I did put the distributor in to replace the coil packs.

Ok so I tried to crank the motor with the jumper disconnected from the relay. Engine wanted to fire right up and ran for a second or two till I'm assuming the fuel pressure ran out in the fuel rail. So it seems if I try use that to ground the fuel pump then the ECU is not able to ground the injectors.

I think I'm just dealing with one underlying issue and that's the fuel pump relay. I'm kind of waiting for an uh-huh moment. I don't know if I've been over-thinking this whole thing or what. I've ran over all the connections and grounds and everything seems ok. Main power and ground go straight to the battery. The second ground from that 8 pin connector was grounded to the battery too but it didn't solve the issue.

The only connections not hooked up are the A/C connections and the two o2 sensor plugs.
jovanbiljon is offline   Reply With Quote Quick reply to this message
Unread 08-17-2014, 10:20 PM   #15
axxxgijoexxxa
Junior Member
 
axxxgijoexxxa's Avatar
1988 YJ Wrangler 
 
Join Date: Nov 2011
Location: olds, alberta
Posts: 95
Just gonna throw this out there for the consideration of those smarter than I. Doesnt the computer put out a lower voltage ( maybe 7volts?) as a reference voltage for sensors and such? As I recall from the rjm site some of the ford computers had slightly different pin-outs from one another, could the computer just not match the harness quite right?
__________________
1988 YJ Laredo (Ford 5.0, AOD, np231, teraflex ssye, 8.8)
axxxgijoexxxa is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.