Hey all,

I have an 88 Ranger XLT Super Cab 4x2 A4ld 2.9 with a fuel problem that's about to drive me out of my mind. Long story short I have replaced the complete low pressure pump assy.,the EEC and the EEC fusible link (with an inline mini fuse). As soon as I go to KOEO the fuse blows. I have figged up a test light and unplugged every plug under the hood and can't get that light to go out. Slap out of ideas and patience.

Help!!!,
Bear

 

Welcome to the forum

So the EEC relays load fusible link melted and now the in-line fuse you added is blowing

Assume 30amp in line fuse

EEC relay has Brown base/socket
Fuel pump relay has Green base/socket

EEC Relay powers:
EEC(computer), two wires to pins 37 and 57 on EEC
Fuel injectors, all 6, red wire daisy chained from one to the other injector
IAC Valve
Automatic trans solenoids, wire runs near exhaust pipes
Fuel Pump Relay's coil(not the fuel pump itself)
WOT relays coil, only used with air conditioned vehicles, WOT= wide open throttle, cuts power to A/C compressor at WOT
WOT has a Black relay base/socket, and empty socket may be there even on non-A/C vehicle, so check for it.

 

Don't think I put anything above 25 amp fuse, but it's a dead short. I have disconnected every plug on the left inner fender and can't get that light to go out. Could I have a bad (or wrong) EEC?

 

25amp is fine, 30amp is stock, but it should never get above 15amps

Unplug the EEC connector and see
Are all the injectors unplugged?

Not quite sure how you are using your test light ?

injectors and fuel pump coil are very low OHMs, so they are almost a dead short, almost being the key word.
0 ohms is a dead short
injectors are 11 ohms
coil is 3 ohms

You really need an OHM meter to find a short on this type of system, because test light will be on all the time with this type of circuit, not an on/off system
Light is good for testing 12volts or 0volts, and might dim with 6volts, but really hard to see a difference on 0ohms brightness and 11ohms brightness

 

I had the test light connected to the pos bat post & the probe in the EEC relay socket. I just put an ohm meter inline, pos lead to neg post and neg lead to EEC relay & get 0.85 ohms.

 

EEC relay socket(load slot) to Ground(battery negative) .85 ohm would be a short
Unplug Fuel pump Relay, see if it changes, thats the lowest OHM device on this circuit
Also move wires around to see if it changes, bad wire
You want it to go up to above 9 ohms at least

Unplug EEC connector
IAC valve

 

Ron,

Sorry for the delay in response, but I am not near the truck right now and I seem to have a difficult time locating this thread. I disconnected the fuel pump at the left inner fender with no change . I also unplugged the distributor and the ohms increased to 1.84. When I disconnect the EEC I loose the short.

 

IAC ? Idle Air Control ? I disconnected that too.

 

Yes IAC = idle air control valve, upper intake next to throttle plate area

I would pop the top on the EEC and have a look inside.

Go here: Ford EEC-IV

Thats what a good one looks like inside, any black/burnt areas would mean time for new EEC

This page also lists the 12volt power pins, 37 and 57, and the Ground pins 16, 20, 40, 60

Test OHMs between power and Ground pins on the EEC,
AND.........on the connector, could have shorted wires but I would expect unplugging connector wouldn't change that

TFI module connects to EEC so it may be OK


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