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Unread 12-05-2011, 02:49 PM   #91
laybackman
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Wouldn't unplugging the TPS cause it to not start anyway?
It should not fire up. Unplug the TPS while it is running also and see what it does....we're fishing for a point to work with here.....

Here is where we are; It starts poorly most of the time and also idles low then dies whenever it feels like it.

You have done a tune up and replaced several key parts and nothing has changed. Since the CEL goes on during the start cycle and goes off once started indicates that the PCM may not be the problem. Either you have a bad intermittent sensor signal or a bad wire interrupting inputs to the PCM would be a very broad and generalized guess.

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Unread 12-05-2011, 03:21 PM   #92
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Gah. Was just out there messing around and I could get it to start using the gas pedal but it wouldn't maintain or idle and just died out. Nothing really changed from this afternoon other than the air is a little more moist. Same temp.

Edit: Also, some kid got wise with me and yelled to me "it's not gonna start, buddy." I thought I had showed him once I got it to fire up a couple times. I guess technically he was wrong because it started, several times. I still feel like I lost.
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Unread 12-05-2011, 03:55 PM   #93
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Not sure how that would cause it to stall out so quickly, though.
x2 for a leaky injector... it could cause the engine to stall out so quickly by flooding it... when they leak they will drip fuel after you let the throttle off flooding it... then after it builds pressure it wont drip as much and alow it to run
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Unread 12-06-2011, 12:13 AM   #94
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x2 for a leaky injector... it could cause the engine to stall out so quickly by flooding it... when they leak they will drip fuel after you let the throttle off flooding it... then after it builds pressure it wont drip as much and alow it to run
Any way to test that?
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Unread 12-06-2011, 12:19 AM   #95
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Any way to test that?
i told you but you ignored my post. i said a few pages back it seems to be a leaking fuel injector and to test it you need to get a fuel gauge and hook it up, turn key on to prime it and get a reading then let it sit and see if the pressure drops. if the fuel pressure drops at all then you have a leak.
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Unread 12-06-2011, 12:25 AM   #96
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i told you but you ignored my post. i said a few pages back it seems to be a leaking fuel injector and to test it you need to get a fuel gauge and hook it up, turn key on to prime it and get a reading then let it sit and see if the pressure drops. if the fuel pressure drops at all then you have a leak.
Oh yeah, I did that...posted a short video of it. Pressure didn't drop quickly. Left it for about 20 minutes or so and it held right around 28psi. Thought that test was for the regulator.
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Unread 12-06-2011, 12:26 AM   #97
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Is your jeep TBI or MPFI
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Unread 12-06-2011, 12:27 AM   #98
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Unread 12-06-2011, 12:33 AM   #99
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test it again and let it sit for 30 mins then come back and check for pressure drop. also let it run and see if pressure drops while its running to see if its a fuel fuel the reason it dies.
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Unread 12-06-2011, 12:34 AM   #100
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Have you replaced your CTS or O2 sensor?
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Unread 12-06-2011, 12:42 AM   #101
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Have replaced nothing. Picked up a crank sensor from AZ against my better judgement and the sensor fit alright but the connector was crap. Didn't make the problem worse or better though so I cleaned off the stock one and returned the crummy one to AZ. I'd have kept it if their connector actually fit all the way on.
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Unread 12-06-2011, 12:45 AM   #102
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lol i bought one a year ago from AZ and the wires were only 4in long and wouldnt reach to the harness to plug in.
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Unread 12-06-2011, 12:47 AM   #103
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Try unplugging your CTS and see if your problem is still there.... Do you have any exhaust leaks around the O2 or before it?
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Unread 12-06-2011, 12:55 AM   #104
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lol i bought one a year ago from AZ and the wires were only 4in long and wouldnt reach to the harness to plug in.
That's what I expected to happen when I saw the short wires, then it surprised me when it actually reached but pressing it into the connector ended up being impossible.


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Try unplugging your CTS and see if your problem is still there.... Do you have any exhaust leaks around the O2 or before it?
Assuming you are referring to the coolant temp sensor? I'm pretty sure I ruled it out when I still couldn't start the Jeep while hot. It would start right back up after about a minute when warm but then when I let it sit about 5, it would go back to cranking forever.

No leaks that I can hear, but I'll check that out tomorrow.


I really want to figure this out before it gets cold out, been working on one piece at a time in the school parking lot. I returned the fuel pressure tester the other day, so that sucks.
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Unread 12-06-2011, 01:03 AM   #105
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Yes I am referring to the coolant temp sensor... And if it starts when it's warm that would mean your O2 sensor is good and hard cold starts might be the coolant temp.... The coolant temp regulates how much fuel is given until the engine is at or close to operating temp then the O2 sensor takes over... So if your CTS is bad it could be telling the computer it is really cold so it gives more fuel than needed causing it to flood and not starting until enough is burnt up
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