Reduced Topic - No Fuel Pump Relay Engagement
07-07-2003, 01:49 PM
#1
Burning Brakes
Thread Starter
Reduced Topic - No Fuel Pump Relay Engagement
Hey Lads,
I thought I would start a separate thread for this since the old thread had more problems. Its down to this now.
The fuel pump relay is not receiving turn-on voltage.
Again, its a 1984 US Model and I cannot figure out why there is no power being sent to the relay engagement pin.
Forgive me, I'm at my regular job right now and don't have access to any manuals.
The brain is new
The injector harness is also new and confirmed good.
The fuel pump relay is confirmed good.
Going on memory here:
The brain sends out a "turn-on" signal to the relay. This gets sent into the "X" plug (last one to the right of the fuse panel). I am uncertain about what else that current passes through on its way to the relay?
I get 12V on one socket only of the f/p relay. I am assuming that this socket is the primary 12V for the pump itself since when I manually depress the relay, the pump works and the car runs.
So, what I need to determine is whether or not there is something that will prevent current from getting to the relay. Factory alarm system comes to mind.
Having said that, here is a brilliant idea that someone can put down:
Can I run a separate wire from the brain harness directly to the relay socket to engage the fuelpump relay? Probably not but it doesn't hurt to ask.
If I can, what is the output pin on the harness that is responsible for this task and to what socket on the relay should I run it to?
Thanx again for all the help lads....
I thought I would start a separate thread for this since the old thread had more problems. Its down to this now.
The fuel pump relay is not receiving turn-on voltage.
Again, its a 1984 US Model and I cannot figure out why there is no power being sent to the relay engagement pin.
Forgive me, I'm at my regular job right now and don't have access to any manuals.
The brain is new
The injector harness is also new and confirmed good.
The fuel pump relay is confirmed good.
Going on memory here:
The brain sends out a "turn-on" signal to the relay. This gets sent into the "X" plug (last one to the right of the fuse panel). I am uncertain about what else that current passes through on its way to the relay?
I get 12V on one socket only of the f/p relay. I am assuming that this socket is the primary 12V for the pump itself since when I manually depress the relay, the pump works and the car runs.
So, what I need to determine is whether or not there is something that will prevent current from getting to the relay. Factory alarm system comes to mind.
Having said that, here is a brilliant idea that someone can put down:
Can I run a separate wire from the brain harness directly to the relay socket to engage the fuelpump relay? Probably not but it doesn't hurt to ask.
If I can, what is the output pin on the harness that is responsible for this task and to what socket on the relay should I run it to?
Thanx again for all the help lads....
07-07-2003, 04:22 PM
#2
Rennlist Member
Rennlist Site Sponsor
How has the fuel pump relay been tested?
There is no usable wiring diagram for the USA '84 fuel pump relay system. It appears to be different from the '83, in that the 12 vdc trigger voltage comes from Z4 (the alarm system) in '84, and internally from the ignition bus on the '83.
Try pulling the Z plug (the right-hand small plug in the center of the board) and jumpering Z4 to Z6 on the board socket. This will be the bottom right terminal and the top right terminal. This will bypass the alarm system.
There is no usable wiring diagram for the USA '84 fuel pump relay system. It appears to be different from the '83, in that the 12 vdc trigger voltage comes from Z4 (the alarm system) in '84, and internally from the ignition bus on the '83.
Try pulling the Z plug (the right-hand small plug in the center of the board) and jumpering Z4 to Z6 on the board socket. This will be the bottom right terminal and the top right terminal. This will bypass the alarm system.
07-07-2003, 05:30 PM
#3
Burning Brakes
Thread Starter
Hi Wally,
The relay we used to test the system was out of a running 83 model.
Are you saying that the relay itself is different or that the path of the wiring is different?
If the relay is not the same, you probably have solved the problem.
I was trying to locate the Z plug but found nothing.
Is the Z plug the black 6 - pole plug dead center of the fuse panel? There are also, what appears to be, 3 power lines in that central location that come in via separate terminals.
With any luck, you may have helped nail this down. Hopefully, the relays may just be different and thats the whole issue. If not, I will try your test and bypass the alarm.
Thanx for jumping in.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
The relay we used to test the system was out of a running 83 model.
Are you saying that the relay itself is different or that the path of the wiring is different?
If the relay is not the same, you probably have solved the problem.
I was trying to locate the Z plug but found nothing.
Is the Z plug the black 6 - pole plug dead center of the fuse panel? There are also, what appears to be, 3 power lines in that central location that come in via separate terminals.
With any luck, you may have helped nail this down. Hopefully, the relays may just be different and thats the whole issue. If not, I will try your test and bypass the alarm.
Thanx for jumping in.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />