askingxforxit

Just put in two new upstream O2 sensors after getting a CEL for bank 1 sensor 2 plus bank 1 too lean codes. Also have multiple cylinder misfire codes, #3,5,6. Acceleration is fine with no hesitation and no loss of power. I am however getting an intermittent rough idle and horrible exhaust smell. Only very light white smoke is sometimes visible but it does look like I've got some black residue on the inside of the exhaust tip. Verified fuel pressure at idle with external gauge approx 48psi. Injectors are from an SR-T4 Neon installed about three years ago or so. Have not done a compression test yet no a vacuum leak test. Other than this the xj runs great. Oh and I've also lost about 4-5mpg.

Thanks in advance for any input guys.

askingxforxit

Bump

Dan_Man

Try hooking up the fuel pressure gauge and routing it between the back of the hood and cowl. So you can read it when you are driving. It shouldn't drop past 45 psi if it does you probably need a pump or have a clogged fuel filter. Most likely the misfire is caused by the lean condition try a fuel leak down test.

1. Disconnect the fuel inlet line at fuel rail. Refer to Fuel Tubes/Lines/Hoses and Clamps for procedures. On some engines, air cleaner housing removal may be necessary before fuel line disconnection.
2. Obtain correct Fuel Line Pressure Test Adapter Tool Hose. Tool number 6539 is used for 5/16" fuel lines and tool number 6631 is used for 3/8" fuel lines.

Fig. 8 Connecting Adapter Tool - Typical

1. Connect correct Fuel Line Pressure Test Adapter Tool Hose between disconnected fuel line and fuel rail (Fig. 8).
2. Connect the 0 - 414 kPa (0 - 60 psi) fuel pressure test gauge (from Gauge Set 5069) to the test port on the appropriate Adapter Tool. The DRB III Scan Tool along with the PEP module, the 500 psi pressure transducer, and the transducer-to-test port adapter may also be used in place of the fuel pressure gauge.

The fittings on both tools must be in good condition and free from any small leaks before performing the proceeding test.

1. Start engine and bring to normal operating temperature.
2. Observe test gauge. Normal operating pressure should be 339 kPa ±34 kPa (49.2 psi ±5 psi) .
3. Shut engine off.
4. Pressure should not fall below 30 psi for 5 minutes .
5. If pressure falls below 30 psi , it must be determined if a fuel injector, the check valve within the fuel pump module, or a fuel tube/line is leaking.
6. Again, start engine and bring to normal operating temperature.
7. Shut engine OFF
8. Testing for fuel injector or fuel rail leakage: Clamp off the rubber hose portion of Adapter Tool between the fuel rail and the test port "T" on Adapter Tool. If pressure now holds at or above 30 psi , a fuel injector or the fuel rail is leaking.
9. Testing for fuel pump check valve, filter/regulator check valve or fuel tube/line leakage: Clamp off the rubber hose portion of Adapter Tool between the vehicle fuel line and test port "T" on Adapter Tool. If pressure now holds at or above 30 psi , a leak may be found at a fuel tube/line. If no leaks are found at fuel tubes or lines, one of the check valves in either the electric fuel pump or filter regulator may be leaking.

Note: A quick loss of pressure usually indicates a defective check valve in the filter/regulator. A slow loss of pressure usually indicates a defective check valve in the electric fuel pump.

Dan_Man

You can also do a fuel volume test by taking off the supply line from the pump and have someone turn the key on for 7 seconds and you should get 1/4 later of fuel.

askingxforxit

Ok I'll try this. Thanks, Dan. I have been thinking the fuel pump/filter is due for a replacement as I'm at about 202,300 miles. Or the CPS

askingxforxit

Really hoping the head isn't cracked too....i have the infamous 0331 :/

askingxforxit

Went to my buddies shop and he plugged in the big snap-on diagnostic tool. Down stream o2 sensors were stuck. Replaced with bosch premium sensors on monday, no idle issues, CEL, or misfires so far.

askingxforxit

So yesterday the rough idle came back and rotten egg exhaust smell. The jeep ran great until then. I'm.starting to think the pre cats are clogged. No other issues to speak of. Anyone have the same problem?

jtm01xj

That smell usually means the cats are going bad or are bad I would recommend going to an exhaust shop and have them check it out to make sure

askingxforxit

Whats the typical life on the pre cats? I have the calif emissions package. About 202,600 miles on the clock

jtm01xj

Every vehicle is different man so there's really no way of telling how long it will last

askingxforxit

Ahh ok. Thanks bro. I'm leaning towards replacing them as I'll be putting some headers in soon anyway.

jtm01xj

Hey if you got the money do it man with over 200 on the clock it wouldn't be a bad idea i bought a 08 e350 cargo van with 133k and it had a bad cat and i got it for real cheep

askingxforxit

Yup, shes getting put in the garage until I get everything ready to put in. looks like the summer car is coming out a couple months early this year!

salad

New O2s are definitely a good idea but have you checked the manifold bolts at the back?