94 Ranger 4.0 not firing right 3 injectors, keeps frying ecu | Ford Explorer Forums - Serious Explorations

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94 Ranger 4.0 not firing right 3 injectors, keeps frying ecu

1994ranger4x4

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94 ford ranger
hey all, howdy from the great state of NH. I'm matt and i run a small shop in Brentwood NH working on cars, trucks, bikes, atv's etc..
Recently my favorite customer(my bartender lol) left me her 94 ranger 4.0 auto 4x4, saying it was lacking power. Well after much hunting around and checking codes, i came to realize the ENTIRE passenger side was not firing. It had great spark, but NO injector pulse.So after tracing back to the ecu, and still finding no pulse, i decided to see if the magic smoke had escaped. Sure enough , i had a burnt spot in the corner of the board near the plug, smelled burnt, looked burnt, etc. i had checked codes and came up with bank 1 lean(makes sense) , a TPS signal Low code, and a torque converter solenoid code. Another thing to note is that she had some sort of issue where the truck would crank and crank and crank occasionally until someone hit the fuse panel underhood( i inspected it and change the fuel pump relay), and that someone had installed a toggle switch on the dash to bypass the cranking function of the key.I believed this to be the reason the ecu fried(backfeeding) and i replaced the ECU.
Lo and behold, she fired up and ran good.....for about 5 minutes till i started drivng her, then the burning smell started again and she ran on the left 3 cylinders only...So I'm banging my head now..I've checked resistance values on the rear two injectors on the pass. side and am getting the same readings.Tmrw i'm going to check the front one once i remove the upper coolant hose.but i'm at a loss as to why only half the injectors die....
HELPPP MEEE!!
 






I had a similar issue on my 94 STX. it began with a bad EDIS module (im sure you've checked that) then in the underhood fuse panel (distribution box) I noticed some corroded connections , turned out the corrosion was making a connection on the underside of the distribution box (in wet conditions) and dead shorting the electrical system.
 






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