92 XJ Limited Edition, will not start. Experienced help needed!!!!

[92XJLimited]

Hi all,

So to give you an idea of my situation I'll give a quick summary.
About a month ago my Jeep severely overheated resulting in me having it towed to my house. The jeep started a couple of days later when I moved it from the street where the tow truck left it, to my driveway. It ran perfectly well before the overheating. However, it didn't run very well (I don't think it was running on all cylinders) when I started it to move it into my driveway. Also the engine sounded like it was cranking faster than normal but it took longer to start. The head was not warped, the gaskets were not cracked.

As of today I have replaced:

Thermostat (old one was pooched, hence overheating)
Heater control valve (broke into pieces when I removed the old one)
cap and rotor (rotor wasn't firmly set in position resulting in bad contact)
Crankshaft position sensor (old one was very magnetized)

As it stands right now, the engine cranks when I turn the key, but it doesn't even sputter a little bit, not even a hint that it's going to turn over. There's plenty of fuel pressure all the way up to the fuel rail, and the new CPS should ensure that the injectors fire properly, so I'm completely stumped as to why it's not going. The fault codes that flash on the dash are 12(flash,pause, flash twice) and 55 (5flashes,pause,5flashes). According the Haynes manual trouble code chart for models '91 and up, there is no listing for "12" and "55" simply indicates that the trouble code sequence is complete. The closest readings to 12 are 11 and 13. 11 states that there's no crank reference signal to computer (hence I replaced the CPS). 13 states that there's no indicated change between "engine off" and "engine on" pressure and that the MAP sensor should be replaced. I've got fuel, I've got plenty of spark. And the new CPS should be telling the injectors the proper times to shoot fuel. So right now I'm all out of ideas. I'm a student and I don't have money to throw at this thing. Hopefully someone else has had the same problem. Please let me know and any help is apprecuiated. Thanks.

 

[Cornflake]

after replacing your cps, you definately have seen spark? i've put on new ones and not had them work. twice now, 2 new ones both dead, different brands, different auto stores. i'd just make sure and not just assume that it is working. beyond that, don't know. always double check and recheck again though.

 

[92XJLimited]

yes we checked last night, pulled off a wire, put in some pliers sat them next to the alternator. The spark bridged easily. This is why I'm so confused.

 

[Onkover]

code 12 refers to the connection to the computer being disconnected in the last 50-100 starts. Check that the connection to the computer is good.

 

[92XJLimited]

code 12 refers to the connection to the computer being disconnected in the last 50-100 starts. Check that the connection to the computer is good.

already pulled the computer off, connections looked fine. still doesn't start. does it matter that that breather tube off the top of the head is missing the connection to the airbox? The little piece connecting it to the airbox was rotten so I removed it awhile ago. Didn't affect it then, don't think that it should this time around.

 

[92XJLimited]

Also, is it abnormal for the temp. guage to max out while the engine cranks? I don't recall it doing this before the overheat.

 

[cklaus]

does the temp gauge read normal after the motor is running? maybe the coolant sensor was damaged from the heat

 

[Ecomike]

Could be flooded with gas. If it is flooded, flooding, push the accelerator to the floor and hold it there while cranking. The computer will cut of the injectors (no fuel) until it dries out and starts.

Not sure which breather tube you are tlaking about, but it sounds like a problem. If you are letting in unfilter air that is not good for the engine and it could be affecting operating vacuum.

 

[Blaine B.]

does the temp gauge read normal after the motor is running? maybe the coolant sensor was damaged from the heat

He doesn't know yet because he hasn't gotten it running.

I know my temp gauge doesn't spike though while starting......95 country.

 

[92XJLimited]

He doesn't know yet because he hasn't gotten it running.

I know my temp gauge doesn't spike though while starting......95 country.

Thanks Blaine. He did bring up a valid point though even though my XJ can't start. I think I read somewhere that the coolant temp sensor will cause the a/f mix to change depending on engine temp. So if, in fact, I did fry the sensor and it's consistently sending the wrong "HOT" signal, then the a/f mix would be too lean for the truck to start. I guess I'll find out today anyway when I put a new sensor in . If it's not that then it's on to the MAP sensor I suppose. God I want to stop throwing parts and money at this thing.

 

[Ecomike]

Thanks Blaine. He did bring up a valid point though even though my XJ can't start. I think I read somewhere that the coolant temp sensor will cause the a/f mix to change depending on engine temp. So if, in fact, I did fry the sensor and it's consistently sending the wrong "HOT" signal, then the a/f mix would be too lean for the truck to start. I guess I'll find out today anyway when I put a new sensor in . If it's not that then it's on to the MAP sensor I suppose. God I want to stop throwing parts and money at this thing.

I ran my jeep (87 Renix) for 2 years without the coolant temperature even connected! Didn't even know I had one at the time!!!!

Also my Haynes clearly says Code 12 is "Battery Disconnected" for your year 1992 (OBD1)!

Have you checked the oil to see if coolant got into the oil when it overheated???

Check the HV wires at night in the dark while cranking (get a freind to help) to see if there are any wires arcing to ground(s).

Pull the spark plugs and check them for water, oil, gas, or crud.

Map sensors almost never die!!!!!! Look elsewhere, save your money!

Further Things to test and check are the:

IAC (Idle Air Controller) (hard to test unfortunately, but can be cleaned. It is next to the TPS which is on the front side of the throttle body.

TPS (Throttle Position Sensor) should read 0.80 to 0.82 volts from C(+) to B(ground) connectors with key in ignition, power on, engine OFF! If the voltage is off, clean your grounds at the engine oil dip stick, driver side valve head and the rear firewall conncetions (2)i and then calibrate, adjust the idle position of the TPS until it reads 0.80 to 0.82 volts.

Intake Air Temperature Sensor in the air intake manifold. If it is bad it will make starting hard by flooding it sometimes (depends on the temp sensor error, if high or low). Test it with and ohm (multi meter) meter.

Check all the vacuum lines!!!!!!

 

[92XJLimited]

I'm just trying to think what most likely got messed up after a severe overheating. NO the oil and coolant did not mix

 

[Ecomike]

I'm just trying to think what most likely got messed up after a severe overheating. NO the oil and coolant did not mix

The two problems may not be related.

 

[92XJLimited]

That's the most concerning part is if they're not related. I'm trying not to just throw parts at it, but aside from the coolant temp sensor, there's no logical progression to give any idea as to what might fix it. I mean it started a couple of days after overheating, and now it doesn't start at all? What could have fried??

 

[92XJLimited]

Any other suggestions?

 

[LiquidOps]

just a curious question... sorry if it's been asked and I missed it....

when you turn the key half way... can you hear the fuel pump kick on?

if not... (problem I had before after it sat for a bit) check the fuel pump relay (maybe not exact term) located on the drivers side fender, top, toward back of engine bay. it looks like a white fiberglass piece with 2 wires going off of it.

pull those... scrape clean the contacts and try again...

just a though...

Steven

 

[92XJLimited]

fuel pump and everything works. just replaced the engine coolant temp sensor yesterday. still no start. like i said earlier, there's fuel pressure all the way up to the fuel rail. i'm gonna replace the plugs today because they're old and even though they're sparking, they may not be sparking quite enough i'm thinking.

 

[old_man]

http://www.naxja.org/forum/showthread.php?t=101119

It is most likely flooded and the plugs are wet fouled.

 

[Tweeternpi]

I had a problem where If I let my set over night it would flood. I had a bad injector that would stay open. One thing to Try is to unplug the CPS. There is a plug at that back of the engine you can unplug it there. Turn the engine over a few times to unflood the engine. Plug the CPS back in and see if it fires. That is what I had to do to mine to start. Pushing the Gas pedal to the floor would not do it.

 

[Blaine B.]

just a curious question... sorry if it's been asked and I missed it....

when you turn the key half way... can you hear the fuel pump kick on?

if not... (problem I had before after it sat for a bit) check the fuel pump relay (maybe not exact term) located on the drivers side fender, top, toward back of engine bay. it looks like a white fiberglass piece with 2 wires going off of it.

pull those... scrape clean the contacts and try again...

just a though...

Steven

Isn't that the ceramic ballast resistor? It's not a relay - it is designed to "quiet" the pump though.

Although yes, they can go bad. Just bypassing it all together will not cause any problems.