I'm having an issue with my 1993 4.0. It will run for a bit, then dies and will not restart. I also have the issue of when driving it short distances, and stopping and restating between stops, it becomes harder to start with each stop. It drags and drags until it finally kills the battery, and requires being jumped. We have replaced several sensors as well, fuel pump... Any suggestions would be great.
1993 Runs For a Short Time Then Dies
- Thread starter kprn1361
- Start date
Fuel pressure?
I’m having a different issue with stalling when I’m coming to a stop. So I’ve been researching stalling YJs and that seems to be the consensus for what you have going on. (It’s been frustrating because I’ve found a lot about your issue but not much on mine)
Good luck!
I’m having a different issue with stalling when I’m coming to a stop. So I’ve been researching stalling YJs and that seems to be the consensus for what you have going on. (It’s been frustrating because I’ve found a lot about your issue but not much on mine)
Good luck!
100+ causes.
Engine. ,spark and fueling (EFI failing) in that order for sure 30 year old cars no tech guesses. He/she tests.
we test for spark first on a dead engine, , watch Scotty K. does it here, 100year old spark testing,, not new, this is how.
I use a new OEM spec, gaped spark plug to test spark or my timing light (tool) can tell it's dead in 1min flat, got tools? can buy some?
you do know this car can have, 3 things wrong and once, and all ignored until now.
or wrong parts on the car
wiring hacks endless (ive just removed all my cars hacks ,just now)
the only consensus is how to test engines, using tools and logic to find the failing path, ASE classes cover that, and is huge consensus.
google is useless on consensus , totally useless.
unless making huge list like below.
I told my DR my toe hurt
he found my finger is broken. as I pushed on that toe.
see?
Engine. ,spark and fueling (EFI failing) in that order for sure 30 year old cars no tech guesses. He/she tests.
we test for spark first on a dead engine, , watch Scotty K. does it here, 100year old spark testing,, not new, this is how.
I use a new OEM spec, gaped spark plug to test spark or my timing light (tool) can tell it's dead in 1min flat, got tools? can buy some?
- what are your symptoms Mr. Kirk (not others) your car your evidence , not told. just stall word.
- got tools , meters and gauges to do test or willing to buy them , not told.
- stalls have vast reasons, EFI ,s park and fueling reasons or even the engine is bad, 30 years .
- got spark? spark plugs 100k miles dead. tune services never done? at 60k miles. filters packed.
you do know this car can have, 3 things wrong and once, and all ignored until now.
or wrong parts on the car
wiring hacks endless (ive just removed all my cars hacks ,just now)
the only consensus is how to test engines, using tools and logic to find the failing path, ASE classes cover that, and is huge consensus.
google is useless on consensus , totally useless.
unless making huge list like below.
I told my DR my toe hurt
he found my finger is broken. as I pushed on that toe.
see?
Last edited:
this is hyjacked post, OP is gone april 2023
in no way is my post guessing, it shows but just few ways it can stall
in MACRO mode (answering) it is
in no way is my post guessing, it shows but just few ways it can stall
in MACRO mode (answering) it is
- engine is bad, (it gets hot and and intake valve sticks) (or in random as all things that stick love to do)
- out of gas LOL> even fuel gauge lies, tell me it can't happen , LOL
- ;EFI is a system and one part of it is bad , even 1 lose wire or rusty or loose ground wire to EFI., spark dies?
- loss of fuel pressure, the FSM told you the EFI brain never knows or tells you fuel pressure is wrong.
- air cleaner packed in rats nest or filter 30 years old never changed, dah?
- critical vacuum hoses fail off or are cracked,
- battery is weak , owner fails to notice dash VM is at 11vdc.? alternator dead or fan belt slips. or missing? but missing it overheats fast)
- lost spark ASD relay drop out.
- fuel pressure 10PSI? 30 at idle it must be.
- flooding, all spark plugs drip raw fuel , or oil or antifeeze pulled?
- injectors leak or clogged half way or intermittent.
- fuel filler 1/2 clogged.
- lose wires to any EFI PCM devices? bad grounds to same.
- vacuum gauge, bounces at idle (1 more tool)
- and more, I have over 50 tests to do, all covered in ASE classes.
- the key on 3 times fast under 3 seconds shows you stored DTC error codes (like DTC 11 up to 55)<< flash codes not stored?
- or just skipping tune ups? 60k mile service points is the modern name now.Phrase.
Last edited:
did you know, any engine this old , when now hot , 180f , you can lose compression on JUST 1 cylinder and if 1 intake valve sticks OPEN?
vacuum goes NUTS. (bouncing like mad)<< never good and never ASSUMED to be good. this old.
this in turn causes misfiring gross and MAP sensor to go mad. too. (MAP IS THE VACUUM SENSOR)
EFI goes mad , (THE PCM CAN NOT HIDE OR SIMULATE DEAD CYCLINDERS EVER) <<<< HARD WARE IS FIRST !
and 02 sensor FRONT lies too. all THIS causes INJECTION RATES DEAD wrong.EVEN FLOODING .
just one small example of just 1 simple failure.
The engine.
the FSM book says, "the PCM can not know ever if fuel pump is weak or if fuel pressure is way way out of spec. (not until later 2020 era)
If lucky it can report lean burn. (see below how)
how ever I can scan this car with my OBD1 scan tool MT2500 (with jeep cartridge 1099) 'SNAP_ON" tools.
and see all DTCs live, even driving.
I can scan all the sensors. to see if one reads wrong , driving. or at any time, key on.
it can report outputs of relays dead, say to the pump.
or worse code 42 ! (the stall code)
I can see this and lots more with this great tool, $200 used cost.
it is a biDirectional tool ,it has an actuator test mode, for relays and injectors and more. ( new and or good 02 is mandatory 100k mile life span)
the right knob there, I scroll and see them all !
data FSM, seen free in the sticky 1.
CODES (flash/blink ) (scan tool or key on 3 times trick)
DTC
1995 FSM quoted (with comments for modern names and causes)
YJ.
DRB means OEM dealer scan tool,rare to find and costly to buy things RARE
I USE MT2500, used, buy snap-on branded with jeep plug in MT25001099
OEM chapter 14-55 up.
11* No Crank Reference Signal at PCM No crank reference signal detected during engine cranking.CKP, CMP sensors bad.
12* Battery Disconnect Direct battery input to PCM was disconnected within the last 50 Key-on cycles. PDC wiring bad?(rusty)
13** No Change in MAP From Start to Run No difference recognized between the engine MAP reading and the barometric (atmospheric) pressure reading at start-up.
14** MAP Sensor Voltage Too Low MAP sensor input below minimum acceptable voltage.
or
MAP Sensor Voltage Too High MAP sensor input above maximum acceptable
voltage.
Map vacuum hose bad ,clogged , or cracked or map bad.
15** No Vehicle Speed Sensor Signal (VSS) No vehicle distance (speed) sensor signal de-tected during road load conditions.
means VSS is dead at tail end of transmission (transfer case 4wd)
17* Engine is Cold Too Long Engine coolant temperature remains below
normal operating temperatures during vehicle
travel (thermostat IS BAD). The STAT has 7 year EOL life span replace it at 5 is best. (overheating engine damage $3000 up)
21** O2S Stays at Center range Neither rich or lean condition detected from
the oxygen sensor input. (center = 0.45vdc) (means it's unplugged most times)
or
O2S Shorted to Voltage 12vdc Oxygen sensor input voltage maintained above
the normal operating range.means heater wire there is shorted to the +CELL 02 pin) replace the O3.
22** ECT (front)Sensor Voltage Too High, Engine coolant temperature sensor input
above maximum acceptable voltage. (means it is bad or wires to it bad) The 02 is bad most times.
or
ECT Sensor Voltage Too Low Engine coolant temperature sensor input below
minimum acceptable voltage. (shorted sensor or bad or shorted wires to it) ECT is on side of thermostat housing.
The sensor at rear of head is NOT IT.
23** Intake Air Temp Sensor (IAT) Voltage Low Intake manifold air temperature sensor input
below the minimum acceptable voltage. It never fails but wires do. (rear intake manifold sensor there)
or
Intake Air Temp Sensor IAT Voltage High Intake manifold air temperature sensor input
above the maximum acceptable voltage.
24** Throttle Position Sensor(TPS) Voltage High Throttle position sensor input above the maximum acceptable voltage.TPS bad, or wires to it bad.
or
Throttle Position Sensor Voltage Low Throttle position sensor input below the minimum acceptable voltage.TPS bad.
25** Idle Air Control Motor Circuits (IAC) A shorted condition detected in one or more of the idle air control motor circuits.
in this case it is BAD IAC or shorted wires to it.
more common is.
IAC is gunked up clean it. found right rear of throttle body, Loctite on threads !
27* Injector #1 Control Circuit Injector #1 output driver does not respond
properly to the control signal. bad wiring , dead injector (coil open/shorted) or wires bad to it.
or
Injector #2 Control Circuit Injector #2 output driver does not respond
properly to the control signal.
or
Injector #3 Control Circuit Injector #3 output driver does not respond
properly to the control signal.
or
Injector #4 Control Circuit Injector #4 output driver does not respond
properly to the control signal. 2.5L ends here.
or
Injector #5 Control Circuit Injector #5 output driver does not respond
properly to the control signal. 4.0L
or
Injector #6 Control Circuit Injector #6 output driver does not respond
properly to the control signal.
33* A/C Clutch Relay Circuit An open or shorted condition detected in the
A/C clutch relay circuit.
34* (means Cruise control in todays jargon)
Speed Control Solenoid Circuits An open or shorted condition detected in the Speed Control vacuum or vent solenoid cir-
cuits.
or
Speed Control Switch Always Low Speed Control switch input below the mini- mum acceptable voltage.
or
Speed Control Switch Always High Speed Control switch input above the maxi-mum acceptable voltage.
35*(XJ Only)YJ has no such thing.
Rad Fan Control Relay Circuits An open or shorted condition detected in theradiator fan relay circuit.) skip for YJ
41** Generator Field Not Switching Properly An open or shorted condition detected in the generator field control circuit.
the 2 nuts on rear of ALT love to rust out,clean them. (or bad alt or slip ring brushes bad)
42* Auto Shutdown Relay (ASD) engine stalls most times. (for sure if ASD drops off line)
Control Circuit An open or shorted "OUTPUT" condition detected in the auto shutdown relay circuit.
ASD trips off line if its output overloads, The spark coil primary shorted, A142 feed shorted. injector shorts., Field coil shorted above.,O2 sensor heater shorted. or fuel pump shorts.
44* Battery Temp Sensor Volts out of Limit An open or shorted condition exists in the en-gine coolant temperature sensor circuit or a
problem exists in the PCM’s battery tempera-ture voltage circuit. not seen on my 1995 ever.
46** Charging System Voltage Too High Battery voltage sense input above target charging voltage during engine operation.
47** Charging System Voltage Too Low Battery voltage sense input below target
charging during engine operation. Also, no sig-nificant change detected in battery voltage during active test of generator output.
bad wiring or bad alternator or belt slips. 120 pounds is spec tension not 20. FSM covers all that. read the FSM.
51** O2S Signal Stays Below Center (Lean) Oxygen sensor signal input indicates lean air/ fuel ratio condition during engine operation.
52** O2S Signal Stays Above Center (Rich) Oxygen sensor signal input indicates rich air/ fuel ratio condition during engine operation.
the below is the scary stuff; (rare as Chicken lips)
53* Internal PCM Failure PCM Internal fault condition detected.
or
PCM Failure SRI Communications PCM Internal fault condition detected.
54* No Cam Sync Signal at PCM No fuel sync (camshaft signal) detected during
engine cranking.
55* Display not shown on oem factory DRB scan tool Completion of diagnostic trouble code display
on the Malfunction Indicator Lamp (Check Engine Lamp).
62* PCM Failure SRI miles not stored Unsuccessful attempt to update SRI (service
reminder indicator) miles in the PCM EEPROM.
63* PCM Failure EEPROM Write Denied Unsuccessful attempt to write to an EEPROM location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded.
Cycle
Ignition key on 3 times, as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
end page.57
vacuum goes NUTS. (bouncing like mad)<< never good and never ASSUMED to be good. this old.
this in turn causes misfiring gross and MAP sensor to go mad. too. (MAP IS THE VACUUM SENSOR)
EFI goes mad , (THE PCM CAN NOT HIDE OR SIMULATE DEAD CYCLINDERS EVER) <<<< HARD WARE IS FIRST !
and 02 sensor FRONT lies too. all THIS causes INJECTION RATES DEAD wrong.EVEN FLOODING .
just one small example of just 1 simple failure.
The engine.
the FSM book says, "the PCM can not know ever if fuel pump is weak or if fuel pressure is way way out of spec. (not until later 2020 era)
If lucky it can report lean burn. (see below how)
how ever I can scan this car with my OBD1 scan tool MT2500 (with jeep cartridge 1099) 'SNAP_ON" tools.
and see all DTCs live, even driving.
I can scan all the sensors. to see if one reads wrong , driving. or at any time, key on.
it can report outputs of relays dead, say to the pump.
or worse code 42 ! (the stall code)
I can see this and lots more with this great tool, $200 used cost.
it is a biDirectional tool ,it has an actuator test mode, for relays and injectors and more. ( new and or good 02 is mandatory 100k mile life span)
the right knob there, I scroll and see them all !
data FSM, seen free in the sticky 1.
CODES (flash/blink ) (scan tool or key on 3 times trick)
DTC
1995 FSM quoted (with comments for modern names and causes)
YJ.
DRB means OEM dealer scan tool,rare to find and costly to buy things RARE
I USE MT2500, used, buy snap-on branded with jeep plug in MT25001099
OEM chapter 14-55 up.
11* No Crank Reference Signal at PCM No crank reference signal detected during engine cranking.CKP, CMP sensors bad.
12* Battery Disconnect Direct battery input to PCM was disconnected within the last 50 Key-on cycles. PDC wiring bad?(rusty)
13** No Change in MAP From Start to Run No difference recognized between the engine MAP reading and the barometric (atmospheric) pressure reading at start-up.
14** MAP Sensor Voltage Too Low MAP sensor input below minimum acceptable voltage.
or
MAP Sensor Voltage Too High MAP sensor input above maximum acceptable
voltage.
Map vacuum hose bad ,clogged , or cracked or map bad.
15** No Vehicle Speed Sensor Signal (VSS) No vehicle distance (speed) sensor signal de-tected during road load conditions.
means VSS is dead at tail end of transmission (transfer case 4wd)
17* Engine is Cold Too Long Engine coolant temperature remains below
normal operating temperatures during vehicle
travel (thermostat IS BAD). The STAT has 7 year EOL life span replace it at 5 is best. (overheating engine damage $3000 up)
21** O2S Stays at Center range Neither rich or lean condition detected from
the oxygen sensor input. (center = 0.45vdc) (means it's unplugged most times)
or
O2S Shorted to Voltage 12vdc Oxygen sensor input voltage maintained above
the normal operating range.means heater wire there is shorted to the +CELL 02 pin) replace the O3.
22** ECT (front)Sensor Voltage Too High, Engine coolant temperature sensor input
above maximum acceptable voltage. (means it is bad or wires to it bad) The 02 is bad most times.
or
ECT Sensor Voltage Too Low Engine coolant temperature sensor input below
minimum acceptable voltage. (shorted sensor or bad or shorted wires to it) ECT is on side of thermostat housing.
The sensor at rear of head is NOT IT.
23** Intake Air Temp Sensor (IAT) Voltage Low Intake manifold air temperature sensor input
below the minimum acceptable voltage. It never fails but wires do. (rear intake manifold sensor there)
or
Intake Air Temp Sensor IAT Voltage High Intake manifold air temperature sensor input
above the maximum acceptable voltage.
24** Throttle Position Sensor(TPS) Voltage High Throttle position sensor input above the maximum acceptable voltage.TPS bad, or wires to it bad.
or
Throttle Position Sensor Voltage Low Throttle position sensor input below the minimum acceptable voltage.TPS bad.
25** Idle Air Control Motor Circuits (IAC) A shorted condition detected in one or more of the idle air control motor circuits.
in this case it is BAD IAC or shorted wires to it.
more common is.
IAC is gunked up clean it. found right rear of throttle body, Loctite on threads !
27* Injector #1 Control Circuit Injector #1 output driver does not respond
properly to the control signal. bad wiring , dead injector (coil open/shorted) or wires bad to it.
or
Injector #2 Control Circuit Injector #2 output driver does not respond
properly to the control signal.
or
Injector #3 Control Circuit Injector #3 output driver does not respond
properly to the control signal.
or
Injector #4 Control Circuit Injector #4 output driver does not respond
properly to the control signal. 2.5L ends here.
or
Injector #5 Control Circuit Injector #5 output driver does not respond
properly to the control signal. 4.0L
or
Injector #6 Control Circuit Injector #6 output driver does not respond
properly to the control signal.
33* A/C Clutch Relay Circuit An open or shorted condition detected in the
A/C clutch relay circuit.
34* (means Cruise control in todays jargon)
Speed Control Solenoid Circuits An open or shorted condition detected in the Speed Control vacuum or vent solenoid cir-
cuits.
or
Speed Control Switch Always Low Speed Control switch input below the mini- mum acceptable voltage.
or
Speed Control Switch Always High Speed Control switch input above the maxi-mum acceptable voltage.
35*(XJ Only)YJ has no such thing.
Rad Fan Control Relay Circuits An open or shorted condition detected in theradiator fan relay circuit.) skip for YJ
41** Generator Field Not Switching Properly An open or shorted condition detected in the generator field control circuit.
the 2 nuts on rear of ALT love to rust out,clean them. (or bad alt or slip ring brushes bad)
42* Auto Shutdown Relay (ASD) engine stalls most times. (for sure if ASD drops off line)
Control Circuit An open or shorted "OUTPUT" condition detected in the auto shutdown relay circuit.
ASD trips off line if its output overloads, The spark coil primary shorted, A142 feed shorted. injector shorts., Field coil shorted above.,O2 sensor heater shorted. or fuel pump shorts.
44* Battery Temp Sensor Volts out of Limit An open or shorted condition exists in the en-gine coolant temperature sensor circuit or a
problem exists in the PCM’s battery tempera-ture voltage circuit. not seen on my 1995 ever.
46** Charging System Voltage Too High Battery voltage sense input above target charging voltage during engine operation.
47** Charging System Voltage Too Low Battery voltage sense input below target
charging during engine operation. Also, no sig-nificant change detected in battery voltage during active test of generator output.
bad wiring or bad alternator or belt slips. 120 pounds is spec tension not 20. FSM covers all that. read the FSM.
51** O2S Signal Stays Below Center (Lean) Oxygen sensor signal input indicates lean air/ fuel ratio condition during engine operation.
52** O2S Signal Stays Above Center (Rich) Oxygen sensor signal input indicates rich air/ fuel ratio condition during engine operation.
the below is the scary stuff; (rare as Chicken lips)
53* Internal PCM Failure PCM Internal fault condition detected.
or
PCM Failure SRI Communications PCM Internal fault condition detected.
54* No Cam Sync Signal at PCM No fuel sync (camshaft signal) detected during
engine cranking.
55* Display not shown on oem factory DRB scan tool Completion of diagnostic trouble code display
on the Malfunction Indicator Lamp (Check Engine Lamp).
62* PCM Failure SRI miles not stored Unsuccessful attempt to update SRI (service
reminder indicator) miles in the PCM EEPROM.
63* PCM Failure EEPROM Write Denied Unsuccessful attempt to write to an EEPROM location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded.
Cycle
Ignition key on 3 times, as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
end page.57
Last edited:
the consensus is , 100 + causes ! ever count every EFI wire? oops. and all power wires and grounds. oops.
I have list of 50 but have never posted it
it be silly to do that.
first learn to scan the PCm
if the PCM knows why and you failed to look, how sad is that.?
good shops can scan cars, but this old most will not even talk to you.
so welcome here we will of you are willing to do the tests, are you?
guessing can be crazy expensive,
one guy did the starter 5 times. and is still bad.
or guy 1 put in the wrong part guessing and now car is dead 2 time over. sad. or worse.
I have list of 50 but have never posted it
it be silly to do that.
first learn to scan the PCm
if the PCM knows why and you failed to look, how sad is that.?
good shops can scan cars, but this old most will not even talk to you.
so welcome here we will of you are willing to do the tests, are you?
guessing can be crazy expensive,
one guy did the starter 5 times. and is still bad.
or guy 1 put in the wrong part guessing and now car is dead 2 time over. sad. or worse.