coreyscx

96 xj jeep cherokee 6 cylinder 4 L

Problem - running rich bad because I'm running lean error code 51 and 52

Things done and replaced - fuel filter, spark plugs, dis. Cap, roter under cap, tps, iac valve, crank sensor, air filter, bottom and top radiator hoses, checked all fuses, fuel pressure test 49 psi, checked injectors they all shoot out gas but randomly. If I crank once for example 1 - 3 shoot crank twice 4 - 6 shoot. Checked for vacuum leaks with some carb cleaner. Haven't checked gaskets but I did check the thermastat housing and valve cover gaskets. I know some of these parts wouldent be the problem I'm just explaining EVERYTHING I checked. NO LEAKS at all. No smoke burning no milky color in oil however I use water not coolent. Also I can smell gas in the oil. But I also have the thermostat out so its not reaching peak normal temp. And last but not least I replaced my front o2 sensor however advance said I got the error code for the o2 sensor high voltage. I think that's about it..but its really chuggin gas and I need some help, oh and the colour of the exhaust is black. Thanks guys.

belvedere

Does '96 have a separate regulator on the fuel rail? If so, unplug the vacuum hose to the regulator. Is there gas in it? If so, the regulator is leaking and the engine is sucking gas in through the vacuum line.

coreyscx

i read from the book that on 96 its next to the fuel pump but i havent quite located it yet thank you ill check that, any other ideas?

belvedere

Off the top of my head, leaky injector maybe?

coreyscx

lol your good, the next things i was going to fix were the orings and regulator, any way it could be the head or intake gasket?

Dire_Wolf

The pressure regulator on the 96 XJ is built into the fuel sending unit which is located on the front edge of the gas tank. You can pull the sender out without having to drop the tank but it is a ***** to get back in and be careful with it as the 96 is the only year they used that particular sending unit on and no one has a re-manufactured one available for that year. I was very very lucky in finding a new old stock( NOS) one but the last one was sold a while ago. Hopefully this helps.

Sounds like it might be your oxygen sensors. I had a similar problem with mine but it was so long ago I can't remember the particulars. Even after I installed two new O2 sensors that I had purchased from the dealer I was still having issues with it running either to rich or to lean. If I remember correctly it was exactly what you are experiencing with your O2 sensor. One of the heater circuits was losing ground so I ended up running a new ground wire to it which fixed the running lean/rich issues.

coreyscx

anything else guys? or are we good on the fact its the orings and regulator? and thanks dire

belvedere

Just re-read your original post. Was the O2 sensor code before or after you replaced it? Have you inspected the wiring for the sensor?

coreyscx

i believe it was before i replaced it but i cannot be sure, also i checked the o2 sensor wiring itself yes but the end hooks into the line that goes up to the top of the engine and into your temp reading sensor for the dash and then the black rail beside the fuel rail

coreyscx

and i didnt check that wiring