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Trying to get my 91 started. Been sitting for a while. Cranks but don't start. Could not hear fuel pump when turning key. Tested Fuel Pump relay-good. What is next step? I was thinking I could check female connections on relay harness at terminals 1 and 2 for coil. After that I'm stumped. I've read very briefly comments about ECM, EEC, and checking voltage at connections at tank, which might require dropping to reach, and of course dropping tank and replacing fuel pump. Can anyone help me out on this? Thanks
 

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I'd bet that the fuel pump has failed. Cut the access hole rather than dropping the tank. Then you can meter the fuel pump connections, and probably replace the pump.
Here's the write up on cutting the access hole. When I replaced my fuel pump, I used an air nibbler to insure I didn't cut any wires or hoses (Air nibbler from Harbor Freight - $20). If you use any spark generating cutting tool (saw or grinder), get your garden hose and continuously spray the top of the fuel tank in case you have any leaks up there, or generate any when cutting the hole.
1983 Ford Bronco Bronco Fuel Pump Access Hole pictures, videos, and sounds | SuperMotors.net

Here's my pictures:



1996 Ford Bronco Misc. Pictures picture | SuperMotors.net
 

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you should be able to check the pressure on the fuel system at the intake...If you aren't hearing the pump it is probably down, but it's pretty easy to check the pressure and ensure it's not getting fuel or if it's something else.
 

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Yo Nitrohound,
WELCOME!
Tech Tip Guide, General; "...Many times, the Ford fuel pump hanger/sender assemblies are frequently found with extensive corrosion on the cover and on the metal tubes. Over time, the terminals can loosen and cause intermittent loss of continuity. Erratic reading of the fuel sender level is one of the other problems that could occur..."
Source: by spectrapremium.com

Also Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....
Do KOEO.

Here is the 1990 F Series/Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manual (EVTM), Partial by member Kingfish999 in Google Drive (similar to your 91) @ 1990 Ford Truck service manuals - Google Drive
Slow scrolling for my slow Comcast Highest Cost Blast Internet..
Find page # of item desired in contents, then flip screen flip down like spinning a bearing then stopping periodically to see what page you are on.
Suggest you download the docs for faster scrolling and to use the page index.

For any questions, or to chat about it's planned build, it's better to post each seperately in Noobie section. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories (75 posts required to view).

To save you time and for better responses, please fill out your Bronco info with location, year, engine size, transmission type, transfer case type (manual or electric shift), locking hub type (automatic or manual) info & major mods such as a Lift, etc. .
Bronco info is now able to be put under your user name.
Click your profile button in the top right and go to account settings.


On that first page, named Account Details, scroll down to "Vehicle Info" and type in up to 100 characters.

Now you can simply enter your information in the text editor and click save.

Our Forum faqs @ FAQ
Includes for example:
How To Upload Images To Posts & How to Use Search
See more tips!

Baba Looey's Favorite FSB Links (lots and lots of tech links) @ Baba Looey's Favorite FSB Links (lots and lots of tech links)

Please find time to participate and VOTE in our Full-Size of the Month (F.O.T.M.) & Full-Size of the Year (F.O.T.Y.) Contests @ https://www.fullsizebronco.com/forum/27-f-o-t-m-voting
You will get ideas by those competing. Also see the prizes⚠ They are awesome as compared to other sites' "contests"!

Al
 

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Discussion Starter #6
I'd bet that the fuel pump has failed. Cut the access hole rather than dropping the tank. Then you can meter the fuel pump connections, and probably replace the pump.
Here's the write up on cutting the access hole. When I replaced my fuel pump, I used an air nibbler to insure I didn't cut any wires or hoses (Air nibbler from Harbor Freight - $20). If you use any spark generating cutting tool (saw or grinder), get your garden hose and continuously spray the top of the fuel tank in case you have any leaks up there, or generate any when cutting the hole.
1983 Ford Bronco Bronco Fuel Pump Access Hole pictures, videos, and sounds | SuperMotors.net

Here's my pictures:



1996 Ford Bronco Misc. Pictures picture | SuperMotors.net
Thank you for your time, and help. That will definitely help, if unfortunately that is next step. Wanted to see if I was missing something before cutting or dropping.
 

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Discussion Starter #7
you should be able to check the pressure on the fuel system at the intake...If you aren't hearing the pump it is probably down, but it's pretty easy to check the pressure and ensure it's not getting fuel or if it's something else.
Thank you, used to hear it run before cranking.
 

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Discussion Starter #8

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Discussion Starter #9
Yo Nitrohound,
WELCOME!
Tech Tip Guide, General; "...Many times, the Ford fuel pump hanger/sender assemblies are frequently found with extensive corrosion on the cover and on the metal tubes. Over time, the terminals can loosen and cause intermittent loss of continuity. Erratic reading of the fuel sender level is one of the other problems that could occur..."
Source: by spectrapremium.com

Also Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....
Do KOEO.

Here is the 1990 F Series/Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manual (EVTM), Partial by member Kingfish999 in Google Drive (similar to your 91) @ 1990 Ford Truck service manuals - Google Drive
Slow scrolling for my slow Comcast Highest Cost Blast Internet..
Find page # of item desired in contents, then flip screen flip down like spinning a bearing then stopping periodically to see what page you are on.
Suggest you download the docs for faster scrolling and to use the page index.

For any questions, or to chat about it's planned build, it's better to post each seperately in Noobie section. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories (75 posts required to view).

To save you time and for better responses, please fill out your Bronco info with location, year, engine size, transmission type, transfer case type (manual or electric shift), locking hub type (automatic or manual) info & major mods such as a Lift, etc. .
Bronco info is now able to be put under your user name.
Click your profile button in the top right and go to account settings.


On that first page, named Account Details, scroll down to "Vehicle Info" and type in up to 100 characters.

Now you can simply enter your information in the text editor and click save.

Our Forum faqs @ FAQ
Includes for example:
How To Upload Images To Posts & How to Use Search
See more tips!

Baba Looey's Favorite FSB Links (lots and lots of tech links) @ Baba Looey's Favorite FSB Links (lots and lots of tech links)

Please find time to participate and VOTE in our Full-Size of the Month (F.O.T.M.) & Full-Size of the Year (F.O.T.Y.) Contests @ https://www.fullsizebronco.com/forum/27-f-o-t-m-voting
You will get ideas by those competing. Also see the prizes⚠ They are awesome as compared to other sites' "contests"!

Al
Thank you very much. I do appreciate the help. Trying to get this going for my boy now. Sophomore in high school.
 

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ate lug
88 + 96 broncos, 96 F250
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  1. Thank you

  2. Thank you very much. Is that the relay harness? Mine is different.
No, thats not for the relays. They are just plugs in the harness, over near the master cylinder & hood hinge, buried somewhere in that corner. They either have nothing connected to them, or they have a dust cover over them to keep the pins clean (i believe it says EEC TEST on the dust cover). They are used solely for testing purposes.
 

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Thank you, used to hear it run before cranking.
Unless you have replaced the fuel filter, it is possible a fuel filter failure or a restriction somewhere as well......eliminate the easy and cheap before going big...if you already mentioned that I'm sorry I must have missed it...
 

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Discussion Starter #12
Unless you have replaced the fuel filter, it is possible a fuel filter failure or a restriction somewhere as well......eliminate the easy and cheap before going big...if you already mentioned that I'm sorry I must have missed it...
Thanks, I don't hear the pump cycling at all
 

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Discussion Starter #13
No, thats not for the relays. They are just plugs in the harness, over near the master cylinder & hood hinge, buried somewhere in that corner. They either have nothing connected to them, or they have a dust cover over them to keep the pins clean (i believe it says EEC TEST on the dust cover). They are used solely for testing purposes.
So fuel pump test socket to right, ground to frame ground? Nothing to do with self test input connection to far left, or other sockets
 

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Yo Nitrohound & "78-79FordMan,
Test & Diagram at the Diagnostic Link Connector in 84-95; "...Connect FP Relay to any ground to force the fuel pump(s) on when the key is in RUN..."

miesk5 note ; from Ford EVTM; The Control Module (EEC, PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pump(s) as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay or the integrated relay control module. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. Pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.
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Fuel Pump Relay has a GREEN Connector, next to Brown EEC Connector Under hood, driver side fender area;7
156118

Location pic in a 90 and all up to 91
Relays were originally mounted such as this;
156119

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reptillikus showed the Self Test Connector for Diagnostic Trouble Codes pic above in post #4.
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GORDON wrote "On my 1990 Bronco the Self Test Connector is located between the air filter cleaner and the brake fluid reservior. It's connected to a stand that sets it up off the wheel well. It's labled but the plug is covered. the plug has to be pulled down out of the cover to plug in the scan tool or to set up the jumper ... to read the codes."
Here are his pics;
156120


156122

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Broncojoe19 describes how to perform the self tests for DTCs @ Code Reader.....
 
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