12-14-2018, 08:23 AM
welcome, I will comment in line....
I have an 87 samurai with a 94 tracker 16v MPFI engine.
It has an issue where it will hesitate or stutter while cruising (not accelerating or decelerating).
Tuneup time,spark plugs wires ,cap , rotor?
It is pretty consistent.
I can't drive for 10 min. without it happening.
It's more noticeable after it's warmed up.
I have also noticed that the idle speed will sometimes drop from 800 to about 500 periodically when it is warmed up or vary between 800 and 500.
top cause of 500 rpm is EGR valve sticking open.
not sure if there's any connection between the 2.
I have seen DTC 21 one time
and 51 a couple times. but does not regularly occur(I have been driving for weeks with no codes.) 51 is EGR failure.
TPS Throttle Position Sensor Circuit too high V , TP pin, not idle pin, bad TPS or ground pin, wire loose or broken.
cruising and it stutters, is misfire. and not TPS cause, the MAF runs fuel cruising for sure if 02 unplugged.
stutter misfiring cruising is spark related, but if spark tips are black or old plugs the plugs are bad or fueling is way rich all the time and is other causes.
If I unplug the TPS the hesitation/stuttering completely goes away. that is because it goes to limphome mode, with very rich fueling.
The idle still drops/varies the same.
If I unplug O2 sensor it doesn't seem to make a difference (good test!)
If I unplug the MAF sensor the idle goes up a bit (around 800 - 1000) hesitation/stuttering is the same. (same thing this is LIMPHOME and super rich no MAF.
I replaced the TPS with a new TPS and it runs the same. (calibrate it first? if not calibrated the tip in throttle hesitates.
if calibrated wrong 2 ways, here is the results.
1: idle switch open all time, TPS no idle controls at all
2: idle switch opens late, hesitation.
Any ideas?
first make sure spark parts are fresh.
then make sure the spark plugs do not burn carbon black on the tips, gap is 0.028" for sure never wider.
the tps calibration is with feeler gauges and a voltmeter key on or ohm meter unplugged. The idle switch pin is the correct pin to measure.
good luck
I have an 87 samurai with a 94 tracker 16v MPFI engine.
It has an issue where it will hesitate or stutter while cruising (not accelerating or decelerating).
Tuneup time,spark plugs wires ,cap , rotor?
It is pretty consistent.
I can't drive for 10 min. without it happening.
It's more noticeable after it's warmed up.
I have also noticed that the idle speed will sometimes drop from 800 to about 500 periodically when it is warmed up or vary between 800 and 500.
top cause of 500 rpm is EGR valve sticking open.
not sure if there's any connection between the 2.
I have seen DTC 21 one time
and 51 a couple times. but does not regularly occur(I have been driving for weeks with no codes.) 51 is EGR failure.
TPS Throttle Position Sensor Circuit too high V , TP pin, not idle pin, bad TPS or ground pin, wire loose or broken.
cruising and it stutters, is misfire. and not TPS cause, the MAF runs fuel cruising for sure if 02 unplugged.
stutter misfiring cruising is spark related, but if spark tips are black or old plugs the plugs are bad or fueling is way rich all the time and is other causes.
If I unplug the TPS the hesitation/stuttering completely goes away. that is because it goes to limphome mode, with very rich fueling.
The idle still drops/varies the same.
If I unplug O2 sensor it doesn't seem to make a difference (good test!)
If I unplug the MAF sensor the idle goes up a bit (around 800 - 1000) hesitation/stuttering is the same. (same thing this is LIMPHOME and super rich no MAF.
I replaced the TPS with a new TPS and it runs the same. (calibrate it first? if not calibrated the tip in throttle hesitates.
if calibrated wrong 2 ways, here is the results.
1: idle switch open all time, TPS no idle controls at all
2: idle switch opens late, hesitation.
Any ideas?
first make sure spark parts are fresh.
then make sure the spark plugs do not burn carbon black on the tips, gap is 0.028" for sure never wider.
the tps calibration is with feeler gauges and a voltmeter key on or ohm meter unplugged. The idle switch pin is the correct pin to measure.
good luck
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