anyone know whats up? maybe XJNick?

[Snitty]

during the summer, i was having a problem with the jeep not starting for me now and then... and it is starting it again... it would always happen when the jeep was warm... it never happened after sitting a while. it would never stall after it has been running, only would not start for me now and then... it definetely seems to be a fuel related problem, much like if i was very very low on gas... crank crank crank brrrrrrrr bup bup... then it will run for about 5 seconds... then start burping for about 20 seconds.. then completely stall... then the second attempt will only give me a few burps... then maybe two... then will just crank and crank and crank with nothing... trouble code 51 always shows up.... lean O2 reading... this could be a bad sensor not reading what is actually coming through, assuming a lean mixture, and supplying TOO much fuel, and flooding it..... or could it be a good sensor reading a bad fuel system? when the jeep sits for about a half hour, i can start it right up with no trouble what-so-ever... that kinda leads me to the assumtion that it is the sensor causing flooding, then by sitting, it always starts up for me....

it doesn't do it all the time... but... it usually does give me a rough idle for about 2 seconds after it idles down from its initial rev... if i keep the rpms up, it can usually stay running... but there are the times it just dies out and leaves me in the parking lot for a half hour or more...

 

[XJNick]

Hi,

That does sound like the 02 sensor could be bad or possibly the 02 sensor wires are damaged. Is it possible that the Catalytic converter or muffler are partially plugged and causing problems?

As far as the fuel system, I doubt the pump has problems (unless it's overheating). So that would leave the fuel pressure regulator possibly being faulty and delivering too little fuel when hot.

Or maybe it's a bad sensor causing the IAC motor to stay to closed, causing the engine to die from lack of air?

However, I'd check and/or replace the 02 sensor first, then go from there :mrgreen:

-Nick :!:

 

[Snitty]

definitely not the exhaust system... all open flow all the way through


yeah... i am planning on checking the wires pretty soon here... i'm not looking forward to buying a new sensor... over 50 bucks just because they are "special"... and.. since you are the obd expert here... what can say to explain that is a more expensive sensor than say... our corsica's sensor

and.. as far as the fuel system stuff.... when i changed my filter over the summer.... the gas that came out of it looked like old used motor oil... quite black, not translucent at all... that tank is pretty dirty, and i'm sure my pump's screen is quite gummed....

i've been lacking power tremendously lately... i hit a VERY flat spot at about 1800-2400 rpm now

this could be the IAC messing with me... symptoms show me that it is lacking either fuel or air... but a motor won't fix itself over time if it is simply leaned out... though it will fix itself over time if it is flooded... that leads me to assume that the faulty o2 sensor is causing the motor to flood... make sense to you?

 

[XJNick]

Well, I certainly don't speak with 02 sensor manufacturers. However, one of the primary cost differences in 02 sensors would be between a Heated and Non-heated 02 sensor. Also, different manufactures use different numbers of pins and connector types, I'm sure they tack on more cost for the various configurations. :roll:

I do still think it's worth replaceing. If you want to test it further, get a scanner hooked up on there and monitor the 02 sensor in real time.

Or you could put an ohm meter across it to test if it's working at all or not. On my '97 you'd put an ohm meter across the two white wires of the sensor, and should get a reading of 5-7 ohms. Infinite ohms means a bad sensor. I don't know if the ohm readings would be the same for a '93, but it's worth a shot anyways to see what you come up with.

-Nick :!:

 

[Snitty]

frame rot

are ours heated?... i hate that... it only takes a mere 2 minutes for an o2 sensor to get unbelievably hot

 

[XJNick]

Well, the one in my Cherokee is. Not sure about the Wrangler, but I'd imagine they are too. Look and see if you have an "Oxygen Sensor Heater" relay or fuse.

-Nick :!:

 

[Bounty__Hunter]

I had the 'dies when warm' problem a while back, it was a bad coil.

 

[Snitty]

i was thinking my coil some time back... it was one thing i haven't replaced yet.. and it is QUITE dirty right now...

 

[Craig]

A guy I work with had a similiar problem last year with his car. If I can remember right, the problem was a cracked distributor cap. When the vehicle heated up, the crack would expand, causing it not to run properly.

 

[Snitty]

that makes a great deal of sense

 

[redrooster]

This may not be related at all, but worth checking. I had similar problems from my old XJ a few years ago. It would run terribly or not want to start. Turned out to be the gas cap. You heard right. The vent spring in the gas cap had broken and the tank would not vent and caused a vacuum on hot days.