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87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
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Discussion Starter · #1 ·
Hello all, i have a problem i cant seem to get fixed. I have an 87 Bronco with a 302 C6 transmission. Ill start by saying there has been several hands over the years on this truck and not all did things the right way IMO. A lot of the plugs and or connectors have been replace/repaired. When i try to start the truck (key in the run position) i can hear relays clicking but no fuel pump. When I turn the key to the off position the pumps prime as they should if the key was in the on position. Another thing is the self test plug isnt working anymore. When i plug code reader into it, it wont start to run diagnostics. I have replaced the ECC, distributor, ignition switch, starter, starter solenoid,fuel pump relay and the EEC relay. The plug on the ignition switch crumbled in my hand when I unplugged it so I am not 100% sure they are in the right place. Also the plugs for the relays were replaced and im not so sure that they are rewired right. In moving with the wires around on the deivers side fender well the fuel pumps quit coming on at all but started working again after a little more wiggling but still ran backwards. I feel like there is just a wire out of place or possibly broken somewhere. ANY help is GREATLY appreciated Im not sure how much more i can take on the truck geez
 

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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941 Posts
Sounds like you need a good wiring diagram to reference for your year to figure out what you have going on. Hold tight, I'm sure @miesk5 will hook you up shortly. He has helped me out tremendously with technical items like this.
 

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1990 EB, 5.0
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419 Posts
Hello all, i have a problem i cant seem to get fixed. I have an 87 Bronco with a 302 C6 transmission. Ill start by saying there has been several hands over the years on this truck and not all did things the right way IMO. A lot of the plugs and or connectors have been replace/repaired. When i try to start the truck (key in the run position) i can hear relays clicking but no fuel pump. When I turn the key to the off position the pumps prime as they should if the key was in the on position. Another thing is the self test plug isnt working anymore. When i plug code reader into it, it wont start to run diagnostics. I have replaced the ECC, distributor, ignition switch, starter, starter solenoid,fuel pump relay and the EEC relay. The plug on the ignition switch crumbled in my hand when I unplugged it so I am not 100% sure they are in the right place. Also the plugs for the relays were replaced and im not so sure that they are rewired right. In moving with the wires around on the deivers side fender well the fuel pumps quit coming on at all but started working again after a little more wiggling but still ran backwards. I feel like there is just a wire out of place or possibly broken somewhere. ANY help is GREATLY appreciated Im not sure how much more i can take on the truck geez
I had an 89 with a similar issue, only it was operator error. I replaced the fuel pump (I LOVE that the fuel pump was on the rail on that thing as opposed to the tank), but I wired it backwards so it de-primed when the key was turned. Anyway, I swapped the wires on the pump and like magic everything worked fine.

In general this sounds like a wire chasing project. Best of luck.
 

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28,815 Posts
Yo Smokey,
Try this ignition switch Logic Test;
Font Rectangle Parallel Screenshot Pattern


The ignition switch, mounted inside column's shroud is where the spring-back from Start to Run is provided, but the actuator(s) is often damaged in tilt wheel.
. If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ford recommends PTFE grease in column. Use powdered graphite in Lock Cylinder Slot.

However, NOTE: Accessories such as radio, etc. that fail to operate with the key in ACC, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Ignition Switch Wiring Diagram in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) by Broncobill78 (Dave)




https://broncozone.com/uploads/monthly_04_2008/post-8965-1208754373.jpg



Rectangle Slope Font Line Parallel

Rectangle Schematic Slope Font Parallel
Schematic Rectangle Parallel Slope Font


Will look for more wiring diagrams.
 

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Registered
87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
Joined
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7 Posts
Discussion Starter · #5 · (Edited)
Yo Smokey,
Try this ignition switch Logic Test;
View attachment 184833

The ignition switch, mounted inside column's shroud is where the spring-back from Start to Run is provided, but the actuator(s) is often damaged in tilt wheel.
. If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ford recommends PTFE grease in column. Use powdered graphite in Lock Cylinder Slot.

However, NOTE: Accessories such as radio, etc. that fail to operate with the key in ACC, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Ignition Switch Wiring Diagram in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) by Broncobill78 (Dave)




https://broncozone.com/uploads/monthly_04_2008/post-8965-1208754373.jpg
 

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Registered
87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
Joined
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7 Posts
Discussion Starter · #6 · (Edited)
Yo Smokey,
Try this ignition switch Logic Test;
View attachment 184833

The ignition switch, mounted inside column's shroud is where the spring-back from Start to Run is provided, but the actuator(s) is often damaged in tilt wheel.
. If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ford recommends PTFE grease in column. Use powdered graphite in Lock Cylinder Slot.

However, NOTE: Accessories such as radio, etc. that fail to operate with the key in ACC, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Ignition Switch Wiring Diagram in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) by Broncobill78 (Dave)




https://broncozone.com/uploads/monthly_04_2008/post-8965-1208754373.jpg



View attachment 184832
View attachment 184834 View attachment 184835

Will look for more wiring diagrams.
I checked the ignition switch and the inertia switch they appear to be working properly.is there a wire or a pair of wires that could be in the wrong location that would cause the oump to prime when the key is turned to the off position and not come on in the start&run position? Sorry if im over looking something its just been one thing after another with this thing ive been on it everyday for 6 mos now. It seems every time i fix something on it 10 more things break or get messed up. Im at the point I’d sell the thing if i didnt have so much money invested in it. Thank you again for your help and patience.
 

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Super Moderator
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28,815 Posts
I checked the ignition switch and the inertia switch they appear to be working properly.is there a wire or a pair of wires that could be in the wrong location that would cause the oump to prime when the key is turned to the off position and not come on in the start&run position? Sorry if im over looking something its just been one thing after another with this thing ive been on it everyday for 6 mos now. It seems every time i fix something on it 10 more things break or get messed up. Im at the point I’d sell the thing if i didnt have so much money invested in it. Thank you again for your help and patience.
Yo,
I'll keep trying to find the ignition switch connector pin diagram.
Here's the better diagram of
Rectangle Font Line Software Screenshot
 

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Registered
87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
Joined
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7 Posts
Discussion Starter · #8 ·
Yo Smokey,
Try this ignition switch Logic Test;
View attachment 184833

The ignition switch, mounted inside column's shroud is where the spring-back from Start to Run is provided, but the actuator(s) is often damaged in tilt wheel.
. If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch
Ford recommends PTFE grease in column. Use powdered graphite in Lock Cylinder Slot.

However, NOTE: Accessories such as radio, etc. that fail to operate with the key in ACC, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Ignition Switch Wiring Diagram in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) by Broncobill78 (Dave)




https://broncozone.com/uploads/monthly_04_2008/post-8965-1208754373.jpg



View attachment 184832
View attachment 184834 View attachment 184835

Will look for more wiring diagrams.
 

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Registered
87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
Joined
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7 Posts
Discussion Starter · #9 ·
Hey man i gotbto going over the wiring AGAIN for the 87th tome and i think i found the issue. On the EEC relay plug the red wire was off by one spot. Thank you so much for all your help and the drawings. Yoj saved my Broncos life lol
 

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87 Bronco Custom 4x4 swapped to 351W, C6, 6” susp, 3” body lifts, 35’s & constantly adding stuff
Joined
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7 Posts
Discussion Starter · #11 ·
Well it did run a little bit nut the timing was off a tooth I believe. I decided to puy ya start button inder the hood so i could start it from outside. On doing ghis one of the best stiluds brokenoff of yhe starter solenoid. So i got another one and a set of spark plugs. Installed edn the starter solenoid and they new plugs, hooked up all the plug wires and coil. Turn ghe key and no fuel pump again. This time its neither of them comes on. So about the only thing I know to do is starr checking wires again does that sound about right?
 

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Registered
1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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941 Posts
Well it did run a little bit nut the timing was off a tooth I believe. I decided to puy ya start button inder the hood so i could start it from outside. On doing ghis one of the best stiluds brokenoff of yhe starter solenoid. So i got another one and a set of spark plugs. Installed edn the starter solenoid and they new plugs, hooked up all the plug wires and coil. Turn ghe key and no fuel pump again. This time its neither of them comes on. So about the only thing I know to do is starr checking wires again does that sound about right?
It would help tremendously if you could edit your post to correct all of the spelling errors so we can make sense of what you are trying to say? (I'm guilty of always editing because of this myself)

Sounds like you think the starter was off a tooth, but you did not say if you corrected it? Then you clipped in a remote start button. Then broke a stud off of your solenoid & you replaced it, but still have no fuel pump kicking on.

When you say the Ignition switch and inertia switch "appear to be working properly" in post 6, can you tell us how you are verifying this? Are you using a test light, or multi-meter to verify power/voltage on the wiring going to your fuel pump?

Sounds like a wire is feeding power to the fuel pump when it's not supposed to be. Like someone tried to jump the fuel pump, and never got it working right, and left it at that & you are left to try to figure it out, which is not fun, but it can be done by confirming voltages, tracing wires thier complete length, to find what is feeding power to your fuel pump when it's not supposed to.

I would think its shorting out when you put the key forward, if that's the case? Which leads me to wanting to know the confirmed voltages coming off the starter, and at the inertia switch, checking and cleaning grounds. One of these has power when it shouldn't.
 
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