2.3L ('83-'97) 2.3 hesitation

[john203]

hello new to the forum. i have a 1991 2wd 5 speed ranger with the 2.3. I'm having a code 28, no tach, and a hesitation upon acceleration. both new coils, all 8 plugs, new wires, new iac gasket, new crank sensor, new fuel pump and filter, new ICM or TFI (whichever). any ideas?

 

[oldgeek]

Does it hesitate on any acceleration or mainly when you want to accelerate quickly from standing still?

 

[franklin2]

Guy in the book says code 28 means the ignition module that fires the right bank of sparkplugs, failed to send a tach signal to the ECA(engine computer).

He says check the resistance between ECA pin 4, and pin 11 on the DIS module. Inspect the terminals on these spots also. If the wire checks good, then replace the DIS module.

 

[oldgeek]

And welcome to the forum.

 

[john203]

Does it hesitate on any acceleration or mainly when you want to accelerate quickly from standing still?

hesitation really anytime after you get out of 1st gear, but under wot it seems fine, myabe a tad low on power?

 

[john203]

Guy in the book says code 28 means the ignition module that fires the right bank of sparkplugs, failed to send a tach signal to the ECA(engine computer).

He says check the resistance between ECA pin 4, and pin 11 on the DIS module. Inspect the terminals on these spots also. If the wire checks good, then replace the DIS module.

are those pins on the top or bottom plug? i just replaced the DIS module (side of intake).

 

[franklin2]

The guy in this book may be wrong. The diagram below shows the tach signal as pin 12 on the DIS module.

 

[scotts90ranger]

The tach is somehow driven by the drivers side coil output in the DIS module, my tach didn't work until that was hooked to a coil... so there's something wrong with the wiring to the drivers side coil or somehow the power or ground to the DIS module. I'm assuming you only bolted it on with the 3 bolts it's held on with from the factory as that's important but even if it's not grounded to those bolts it'll run fine for a while then just stall not what you're getting (I know from experience, how I rolled my '90)

 

[john203]

UPDATE:
since this forum is almost useless in terms of updates of fixes or anything, i'll contribute mine. after inspection of the wiring, and checking for continuity on the harness. i found the red w/ green tracer wire (middle wire, lower coil pack plug) had a ~1/4" section that had rubbed the power steering return hose, and all the wire was gone. it was corroded all the way up into the plug and about 6" back into the harness. after cutting back the loom, stripping back the harness to a good section of that wire, de-pinning the plug and removing the middle pin/wire, and letting the pin end of that wire soak in some cola, i spliced in a new wire. reset codes, and it fired up with tach in operation and no more hesitation/missfire. thanks for anyone who helped me with this.

 

[john203]

 

[scotts90ranger]

That is completely crazy and would definitely cause that issue! Like I said the tach is driven off of that side and relies on the coil working which it won't without the power wire in the middle.

Glad you got it working!