fuel pump/eec relay issues

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lonestarbronco

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Need some input from the fuel injection gurus out there. My fuel pump relay is clicking like its sending morse code, very erratic like. It wont start so Ive been reading it could be either the fuel pump relay itself or the EEC relay. My question is whats the difference between the two relays? They look identical to me but thats why Im asking the pros. Also if anyone happens to have part numbers for the two it would be very much appreciated. Thanks in advance guys.

89 Full size

302ci

E4OD trans

 

Seabronc

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Welcome to the Zone !!

The two relays are the same.  You can try swapping them, but if the fuel pump relay continues to operate erratically then the relay is not the problem. 

:)>-

 

miesk5

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Yo lonestarbronco,

Welcome!

As Fred advised.

And look for corrosion in the reads sockets and on relays.

Fuel Pump Circuit Operation

When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link attached to the starter solenoid (battery side). From the fuse link, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."

Here is your 89 wiring diagram,

http://www.supermotors.net/registry/media/851783

by Ford via SeattleFSB

SeattleFSB has more @ http://www.supermotors.net/registry/20487/76449

 

miesk5

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Yo,

Corrosion in socket is usual suspect causing intermittent connection due to location.

2nd is wiring at socket could be loose causing intermittent connection.

Just like a loose light bulb in its socket at home.

 
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lonestarbronco

lonestarbronco

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replaced both relays at the same time. Still no dice after cleaning the connections, however if i put a jumper wire in the EEC port instead of the relay the pump will kick on. its not starting the engine but at least I know the in tank pump is getting power. There could still be a stoppage somewhere between the inline pump and the engine. Maybe the lines or the fuel filter are clogged. Any other suggestions or ideas why I have to jumper wire the EEC port to get power?

 

miesk5

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Yo,

Battery must be fully charged with nd no load should be at least 12.6 volts depending upon meter accuracy.

Did you do this to get the pumps running?

Test & Diagram at the Diagnostic Link Connector in 84-95;

Grounding the FP lead at the DLC will allow the pumps to run continuously with the ignition switch on.

http://www.thedieselstop.com/faq/9497faq/maint/vra/images/a9465b.gif

Anyway, the pumps are working. Is the FP Relay still chattering? If so, check at EEC relay for intermittent battery voltage at White/light blue wire from ignition switch and continuity to ground on black wire to ground G801 On LH inner fender behind headlights.

*** Check that Ground first.***

If intermittent voltage from ignition switch; Switch Pin-Out Diagram & Continuity Testing (Logic Tables in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) by Broncobill78 (Dave) at

http://web.archive.org/web/20110909003616/http://broncozone.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=6659

...

If not intermittent, check Yellow wire at EEC relay for battery voltage from fusible Link N.

If ok...

KAPWR is Keep Alive Power at EEC pin #1, Yellow from same Link N

Pin 37 Red wire, Circuit 367 is VPWR -Vehicle Power supply voltage (regulated 10-14 volts)

Did I cover the FP AND EEC Relay Circuits?

Am typing on a cheap tablet and can not scroll back in edit mode. Am editing to add info from "If ok..." to here..

---------

BTW,

Single-Function Reservoir in 84-89; "...The PN for the filter is given, but you shouldn't actually have a filter in there. It should be an external inline filter further up the frame rail - you only buy the reservoir filter to get the O-ring, and only then if you have some reason to open the reservoir bowl. Unless you're having fuel delivery problems that you've isolated to the reservoir, you should never open it..."

The single-function reservoir (SFR) is used on vehicles with ONE gas tank, like Broncos, vans, & low-trim pickups. The reservoir is always inside the L frame rail beneath the driver's floorpan about 10" behind the frame fuel pump. The 10mm bolt heads are easy to access on the outer face of the frame rail, but some vehicles have a large heat shield that must also be removed...There's not much to the SFR (which is what ALL Broncos of those years have): the '88 version just has the cup & 1 check valve (earlier versions have 2), but it's almost foolproof... the only moving part is the tank-side inlet check valve. The return ports flow freely and are NOT connected to the reservoir. The engine-side supply port is open to the reservoir. To test it, unplug the frame fuel pump, disconnect the engine-side supply (large) line, and cycle the key. If fuel flows out of the reservoir ******, the reservoir is working normally. If not, disconnect the tank-side supply (large) line, and cycle the key. If fuel flows out of the line, the reservoir check valve is probably stuck, or its internal filter is clogged. A reservoir marked "DO NOT REMOVE CUP" does not contain a filter. For a replacement O-ring for the cup, buy a NAPA 3268 (or equivalent) filter..." by Steve.. Steve deleted reservoir info above from the Broncozone.

For some reason I have not been able to insert pics, except for thumbnails here for a long time since I do not see the icons for pics.

 
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lonestarbronco

lonestarbronco

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I'm still jumping the relay but I replaced the inline pump and am now getting fuel past the filter up to the engine itself. So now it's gotta be fuel rail/injectors or an ignition problem. Slowly but surely I'm getting there. Thanks for all the input y'all.

 

miesk5

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Yo,

So, the FP Relay is not clicking now?

And pumps do not run without the jumper?

Fuel Pressure Regulator Test;

Remove vacuum line, any gas aroma or gas, replace the FPR.

 
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lonestarbronco

lonestarbronco

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The pumps do not run without the jumper. I replaced the ignition coil and the engine will start but it dies immediately. I still need to figure out why Im having to jump the realy to power the pumps though.

 

miesk5

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Yo,

Can you answer the questions that I posted in #7?

And if If not intermittent, can you check Yellow wire at EEC relay for battery voltage from fusible Link N?

If ok..., Switch Pin-Out Diagram & Continuity Testing (Logic Tables in 87-91 .. can you do this?

 
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lonestarbronco

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yea I jumped the EEC relay just to make the pumps run, which they do and im getting fuel all the way to the engine, when i do the FP relay isnt chattering.

On the other end of the spectrum, what would cause the engine to just shut off? Some of the things I have read point to the MAP sensor being the issue. How much validity is there to this?

 

miesk5

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Yo, ok

Usually the MAP would pop a code.

Code 22: MAP Sensor Out of Range.

Code 72: Insufficient MAP Change During Dynamic Response Test.

You'll also experience:

Engine cranks for a long time before it starts.

When the engine starts, you get a lot of black smoke coming out of the tail-pipe.

Engine stalls as soon as it starts.

If the engine stays running, it idles very rough.

If the engine runs, you'll get really bad gas mileage.

Can test it..http://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-test-the-map-sensor-1

........

Look at the tests I suggested in post #7

If you can not get a chance to perform the tests, at least you will know what a shop should do instead of swapping parts.

BTW, when you jumped the EEC relay it bypassed the ignition switch, eec relay and eec.

 
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lonestarbronco

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Also, Ive successfully used the self test mode in the past to flash codes but for some reason now it wont flash anything. I guess after sitting for a decade some things go out.

 

miesk5

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Yo,

OK, try this;

Self Test - Scan Tool Won't Initiate Self-Test Due to Poor Grounds, Corroded Wiring, etc.; read more on how to Ground the STI & Proceed w/ Test

poor-ground.jpg

by Jeremy Millrood

 

miesk5

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Yo fd3etty,

Welcome!

Start a new post with all the issues.

Describe what is happening.

Is check engine light on?

Does engine crank over?

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19 @ http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded

If its a cranks but no start, do KOEO & post any codes found.

Keep each post limited to one issue.

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