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Unread 01-23-2012, 07:21 AM   #76
Que89YJ
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Any update?

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Unread 02-18-2012, 10:57 AM   #77
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Sorry for the long delay. Today is the first day that the weather was half decent and the wifey wasn't nagging that I wasn't spending any time with the family. I hear that this is a known issue with Jeep owners. ;-)

Ok, I bought a fuel pressure test kit. Hooked it up and tried it out..

Test #1, initial test - first time starting Jeep in two weeks.
Attached it to the schrader valve.
Ran the Jeep for a minute and it stayed steady at 32psi.
Shut it off and the pressure went to 20psi and began to slowly decrease.

Test #2, disconnecting vacuum.
Started the Jeep, 32psi and steady.
Disconnected vacuum and it increased to 40psi (maybe 42).
Reconnected vacuum, engine groaned for a second and idled normally.
Pressure is now wiggling between 40 and 50psi.
Shut it off and pressure went to 30psi.

Test #3
, reset computer.
Disconnected positive terminal, held it to body for 20 seconds and left disconnected for two minutes.
Confirmed computer only gave 12 & 55 codes.
Started it back up and pressure wiggles between 34 and 42psi.

The tester has a release valve and I have emptied the gas and started it up again from zero and the results were the same. I did this twice to confirm no false readings, for test #3.

So now the question is, by disconnecting the vacuum and reconnecting it, did I put the final nail in the coffin to the fuel pressure regulator, which was probably already on its way out?
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Unread 02-18-2012, 11:21 AM   #78
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Okay, 20 minutes have passed and I just went back out and tried it again. I started it up, and at first it wiggled between 30 and 38 psi and then immediately went down to 30 and 32psi (wiggling). I shut it off and tried again, same readings.

I revved it a couple of times and it did wiggle up and down for a short moment but it's still wiggling between 30 and 32psi.

I find it interesting that for my very first test, it stayed at 32psi and didn't budge. Now it wiggles. Is it because now that the engine is a bit warmer than before?

Also, and I'm not sure if this is related or not, but it's spitting out a lot of condensation from the exhaust. My car is parked behind it and part of the front bumper, that's in behind the Jeep's exhaust, is covered with dark liquid. It produced a small puddle beneath the exhaust. Again, black-colored water. Because it's been idle for a while?
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Unread 02-18-2012, 01:42 PM   #79
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Yes, the black liquid is because its been sitting a while. No harm, it just needs regular exercise. Run it every day till the engine is good-n-hot.

The wiggling and variation is likely just sloppy vacuum fitting where the line attaches to the regulator - I used miniature hose clamps on both ends of all my vacuum lines, it made a big difference in how smooth it pulls. It brought the fuel pressure down to where it should be, and made everything very stable.
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Unread 02-19-2012, 06:58 PM   #80
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Should I drive it for a week and retest? Otherwise, the fuel pressure test indicates that it's getting the correct pressure.

Am I left with a possibly bad / going bad cat? I replaced it five years ago, though the outer heat shield has already rusted off (gotta love the northeast).
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Unread 10-31-2012, 01:14 PM   #81
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Here's an update, but it's not really an update... I've replaced the Oxygen Sensor a third time, I'm still getting the same results. Three sensors, three different brands, same results.

Tested the MAP Sensor and the readings are normal.

Fuel pressure is normal / acceptable. (link to post)

Same old story... disconnect the battery and it will run for about four to six trips (engine on, drive, engine off) before it begins to idle rough and it gives me code 52.

I don't drive it enough for the plugs really to show wear from it running rich, but there is a gas smell after I get out. I check the floor beneath the Jeep and see no signs of any leaking.

I've run out of things to check and/or replace.
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Unread 10-31-2012, 08:08 PM   #82
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What kind of sensor did they put in? It's worth it to get a Delphi unit; they're the oem supplier. My exhaust shop said dont even bother with Bosch.
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Unread 11-01-2012, 10:49 AM   #83
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The first one was Bosch, don't recall what the second brand was (got it at CarQuest), and the brand that's in there now is Delphi.
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Unread 11-01-2012, 11:49 AM   #84
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Code 52 = rich air fuel mix.

The O2 sensor is detecting free oxygen level above acceptable levels in the exhaust stream. That is all it does. But the signal it sends back to the brain controls fuel levels injected into this engine also to alter the air/fuel ratio.



IF you have no vacuum leaks in the exhaust stream before the O2 sensor and your air filter is nice and clean you may not be getting complete combustion. That would allow free oxygen in the exhaust stream which the O2 sensor then detects.

Are you running this engine hot enough? It wants 210F.


And I would make sure that the spark plugs are in the right heat range for this engine. Stay away from the fancy schmancy plugs. By Autolites or Champions and make sure they are gapped properly!

Don't trust the gap on your plugs when they come out of the package.
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Unread 11-04-2012, 11:18 AM   #85
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My thermostat is the 190F one. I just drive it to work, which is 30 minutes in each direction and it does reach operating temperature for the duration of the drive.

I believe the plugs I have are Champions. I bought a 'tune up kit' from Quadratec a couple of years ago and replaced the plugs, plug wires and distributor cap. I read up on this forum to find the gap for the spark plugs and properly gapped them to the spec (I may have read it in my Haynes manual, I don't remember).

I think the voltage I got on the MAP sensor was about 4.8 volts (IIRC, it needs to be between 4.5 and 5.0). Now when I checked the MAP, the engine was cold and I didn't let it get to operating temp. That's about the only thing that I can think of that would be out of the ordinary). The other fuel pressure test and checking the voltage on the O2 sensor, were all done when the engine was at temp.
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Unread 11-04-2012, 12:59 PM   #86
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Quote:
Originally Posted by Bad_Dog View Post
My thermostat is the 190F one. I just drive it to work, which is 30 minutes in each direction and it does reach operating temperature for the duration of the drive.

I believe the plugs I have are Champions. I bought a 'tune up kit' from Quadratec a couple of years ago and replaced the plugs, plug wires and distributor cap. I read up on this forum to find the gap for the spark plugs and properly gapped them to the spec (I may have read it in my Haynes manual, I don't remember).

I think the voltage I got on the MAP sensor was about 4.8 volts (IIRC, it needs to be between 4.5 and 5.0). Now when I checked the MAP, the engine was cold and I didn't let it get to operating temp. That's about the only thing that I can think of that would be out of the ordinary). The other fuel pressure test and checking the voltage on the O2 sensor, were all done when the engine was at temp.
This engine should be running at 210F. You need to go with a 195F thermostat.
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Unread 11-04-2012, 01:28 PM   #87
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Have you checked for leaking injectors by doing a fuel pressure leak down test?
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Unread 11-04-2012, 04:25 PM   #88
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Quote:
Originally Posted by laybackman View Post
This engine should be running at 210F. You need to go with a 195F thermostat.
I replaced the thermostat when I bought the Jeep in 2004. Aren't there generally two temperatures for thermostats - 180 and 195? If so, I bought the 195 one; I know that I didn't buy the 180/185/180'ish thermostat.
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Unread 11-04-2012, 04:27 PM   #89
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Quote:
Originally Posted by Why J? View Post
Have you checked for leaking injectors by doing a fuel pressure leak down test?
Negative. I think that would involve a little more knowledge of engines than what I possess, so I wouldn't even know where to begin or what would be involved.
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Unread 11-04-2012, 07:58 PM   #90
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How does this engine idle? If it idles rough I might suspect bad injectors because they are clogged up.


BUT if you have injectors that allow too much fuel into the engine because the injector ports are worn then it is possible that you are getting too much fuel for complete combustion which may cause your code 52.....

Next, I wonder why once you clear the DTC's that it take several days or weeks before code 52 does pop up again?

Thought...If you had bad injectors pouring too much fuel into your engine, wouldn't code 52 pop up as soon as this engine warmed up and went into closed loop mode? I'm a bit
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