2.8 Stalls and hesitates

[Welder0800]

Hello all. Haven't been on here in a while but I am currently having a problem with my truck. Had to finally replace my 89 ranger so I got an 85 in June. It has always run slightly rough but nothing to bad but lately it has gotten worse. The truck will shut off when you come to a stop and if it doesn't at first it will shut off shortly after stopping. Within the past couple weeks it has started to really hesitate when accelerating to the point where it almost seems like its gonna shut off. She's a 1985 Ranger 2.8L 4x4 with a 5 speed. It seems like a fuel problem but im kinda at my whit's end here so any help would be appreciated

 

[RonD]

When was the last time the carb was rebuilt?

Could be time to do that, good read here: http://www.therangerstation.com/tech_library/pdf_documents/motorcraft_2150_carb.pdf

TFI ignition systems have problems as they get older, good read here: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

Print worksheet and follow it to test for problems


Also test battery voltage before starting engine, needs to be above 12.2 volts
Then test battery voltage after engine has warmed up and is idling, should be above 13.4 volts.
Alternators have 3 separate fields inside that generate power, as alternator gets older 1 or even 2 fields can fail, this is often seen as headlights dimming at idle(no that is NOT normal, lol)
At higher RPMs alternator can maintain battery and system requirements with a failed field, but at idle it can not, as voltage drops the spark also gets weaker, as engine misfires RPMs get even lower and so does the voltage, so even weaker spark until engine dies.
With the weak spark and added fuel from pushing on gas pedal engine can start to stall out until voltage comes up with RPM increase

 

[Welder0800]

As far as I know carb has not been rebuilt but I've only had it for 5 months or so. I've thought about rebuilding it but was unsure if I'd be able to pull it off as I've only rebuilt an Autolite 2100 off that 65 I've got. Appreciate that guide RonD. I'll let y'all know what ends up happening.

 

[kimcrwbr1]

If it is still running on the computer it is the 2150a carb. Real similar to the 2100. Be sure and count the turns on the slow needles and set them back there. You can pull the codes but the first thing to do is make sure all the sensers are connected and the vacuum lines are correct. If you dont need to pass emissions do the duraspark conversion and ditch the computer.