here s the problem, 87 ranger 2.9 4X4 auto,runs like crap when ever it feels like it. when problem occurs it shoots black smoke out tailpipe, going into a full rich condition, sometimes it'll do it at an idle for 30 seconds and then will fix it self. the injector pulse does change between when it is running good and bad so i know some thing is telling the computer to run rich at times.
parts tested or substituted with used or new include-
-computer, map sensor, coolant temp sensor, tps, oxygen sensor, ignition module, removed wiring harness from truck and checked for rubbed through wires, cleaned grounds, made sure rite starter solonoid was on truck, unplugged egr& exhaust pressure sensor,
- we are thinking along the lines now of a injector solenoid shorting out once in a while

we are hoping that the ignition switch starts on fire and burns the truck, then i don't gotta worry about it.

anybody got any clues to get this ranger back on the road

 

Chk the fuel pressure regulator when they fail you dump raw fuel into the intake through its vacum line. had a bronco 2 that did this.

Rich

 

yea, we ran the truck with that vacuum line unhook and test drove it. it would still act up usually after 1/4 at 80 km but now it acts up sometimes in 50 feet or after a 10 mile run. the fuel pressure was about 35 40 psi i belive with the regulator unhooked. we are pretty sure it is a computer problem because of the way the injector pulse changes when the truck starts running bad, then all of a sudden changes the injector pattern and runs 100%. i think i've run out of options. i just wonder if an injector is shorting out and screwing up the computer

 

please post back when you get yours figured out and let me know cause myne is similar in the way it acts. so please let me know what you have to do to it.

 

turns out it was the o2 sensor, when it got up to a certain temperature it would screw up

 

well my connector has melted and the tfi is bad so i gotta fix this.

 

the connector on this one was melted to, just unhook yours and take it for a drive and see if it fixes it. why change the module? only change it if the truck don't run or quits when driving or won't restart when warm

 

the tfi is bad. i already had it tested and it failed three of the testies. the dwell is the only one i can recall the name of though. as for my connector there is no unhooking it. its melted together. so im gonna cut the wires and make my own.