this is bad indeed.

[malton]

been trying to get my xj running on me own, to save labor costs (unemployed, must scrimp). but after running one week out of every four or five since august, i gave up in frustration yesterday and sent it to the only mechanic in this area that i trust. it's still doing the same thing: run a bit, die (neither engine temp nor speed are factors), refuse to crank for a day or so...also is running extremely rich. so i gave him a written record of everything i'd done to it. he sez:

"i have no idea what to tell you; you've replaced everything that would cause your jeep to do this."

FOOK.

funny thing is, another customer of his brought in a 97 with the same issue. same day. perhaps it's an unknown virus...

 

[TerryMason]

Malton - what year is your Jeep (you may want to fill in this http://www.jeepz.com/forum/profile.php?do=extra so that people can tell in the future).

 

[tessa]

Out of curiosity, what things have you replaced? What things have you run diagnostics on? Alternator? Battery?

 

[malton]

Malton - what year is your Jeep (you may want to fill in this http://www.jeepz.com/forum/profile.php?do=extra so that people can tell in the future).

sheesh, musta forgotten to click "save" or something. got a 93 xj country, 4.0

replaced the following:

FUEL
pump/strainer/filter/pressure regulator/injectors (also had to clean the tank and blow out the lines)

FIRE
plugs/cap/coil/rotor/wires

SENSORS
throttle/idle/crank/coolant temp

ELECTRICAL
alternator/battery/ASD relay

OTHER
air filter/thermostat

CHECKED:
map sensor/O2 sensors/fuel pump relay and ballast resistor/all fuses

WAITING IN THE WINGS:
pcm i picked up secondhand at a parts yard (aftermarket from an XJ w/similar mileage, i'm assuming it's good)


jeep's got a little over 225k, a lot of what i mentioned above was coincidental breakage, some of what i mentioned above was brought on by my own stupidity...lessons learned. i'm thinking after talking to a friend who had the same issue a couple years ago...my jeep's pcm is original, and just might be the culprit...thoughts?

 

[TorqueWinsRaces]

When you say "refuse to crank for a day or so", do you literally mean there is no power being applied to the starter? It is not cranking over? No clicking? Just "dead"?

I know this sounds crazy...Have you had you battery load checked? On a computer-controlled vehicle if the battery starts to go south- lose a cell or whatever- it can wreak havoc on a PCM. Makes 'em do all kinds of crazy stuff.

 

[malton]

no no no no. sorry--lacked some clarity. turns over, but won't start. battery's fine.

then again...old battery got killed by the alternator when it crapped out, and the one i have is the SECOND replacement--first one was defective. is it possible then that something in the pcm got a bit cooked?

 

[88Wrangles]

Is the CEL on? even if it's not, check and see if there's any old fault codes stored in there

 

[89 jeep yj]

Have you checked the ignition module?

 

[SteelHeadz]

no no no no. sorry--lacked some clarity. turns over, but won't start. battery's fine.

then again...old battery got killed by the alternator when it crapped out, and the one i have is the SECOND replacement--first one was defective. is it possible then that something in the pcm got a bit cooked?

It's possible.. A spike in the electrical system causes havoc in any computer controlled vehicle. Edited:Go back to the Basics. Check for fuel and Spark to see which direction you need to go to diagnose and isolate the problem.

 

[malton]

codes 12 and 55.

got spark, got fuel--rich, but pressure's right where it should be.

 

[SteelHeadz]

Code 12 would be a Map sensor code. Code 55 is just a completion code for the DTC display.

 

[tessa]

codes 12 and 55.

got spark, got fuel--rich, but pressure's right where it should be.

Well, code 12 means "no distributor pulse" and 55 means "ECM fault"...

Hope that gives you some direction

 

[SteelHeadz]

Well, code 12 means "no distributor pulse" and 55 means "ECM fault"...

Hope that gives you some direction

Code 11-nocrank reference signal at PCM
Code 53-internal PCM failure
Code 54 -no Cam sync signal at pcm

Update: On a 94 Jeep XJ 4.0 Service manual, Code 12 is a Battery Disconnect.(Direct Battery Input to PCM was Disconnected within the last 50 key-on cycles.

 

[tessa]

Code 11-nocrank reference signal at PCM
Code 53-internal PCM failure
Code 54 -no Cam sync signal at pcm

Update: On a 94 Jeep XJ 4.0 Service manual, Code 12 is a Battery Disconnect.(Direct Battery Input to PCM was Disconnected within the last 50 key-on cycles.

Heh. Well thats what I get for looking at generic DTC's instead of specific by year huh?