Sluggish engine MAF stalling etc fixed

[1991_4wd]

Hello all...great forum.

 

anyways I traced the problem back to the MAF when I realized that air temp had a large effect.

 

symptoms

 

stalling, sluggishness

surging when warm

cars runs temporarily when restarted.

(rarely, engine shut off with hood slam)

 

Misdiagnosis

 

fuel pump

fuel filter

airbox leak

stuck lifters

clogged cat

other sensors

IACV

 

 

Diagnosis

 

I noticed air temp effected drivability and stalling considerably, decided it must be MAF temp sensor.

 

removed MAF the second time, and decided to disassemble.

 

MYSTERY SOLVED.

 

when the plug jack was removed with the screws, i noticed that it easily pulled out, however those pins where supposed to be soldered to another set of pins, instead there was classic white solder core corrosion. it had completely removed the solder.

 

(note: bimetallic junction caused a degradation of the solder joints over time. 25yr in this case)

 

SOLUTION (vs. buying a $50 MAF from ebay and putting on)

 

cut away the top material or the side of the plastic MAF housing with a small knife to expose the tarnished pins behind the plastic housing. you could surgically remove the top of the housing above the female connector carefully with a razor or hacksaw..recommend against a dremel. See if you can unscrew and pull the connector out.

 

screw on the female connector (could seal with silicon rtv to prevent this)

scrape pins clean with a knife or small file. get some nice rosin core solder on all 4 pins...i prefer using lead free tin solder.

 

now replace the top or seal up the maf somehow (glue on a small piece of plastic for example.

 

bingo, you have a new MAF minus the corroded pin connection.

 

screw the throttle plate back, put back to stock if any mods where made. maybe 2 turns in.

 

unplug batt 30 min, let idle 10. should drop to 750-800

 

once doing this car is like new again...no issues.

 

man this issue was so maddening i thought is was a conspiracy for a minute.

 

finally, i can get to putting on that cat back straight pipe and Short Ram Intake. anyone try that AMS synthetic rear diff lube?