jeepboy4life

This morning my 96 started a little harder than normal which okay, its a XJ this happens, but the about 200 yds down the road my jeep died and started very hard, took me 5-6 times to get it. It hasnt been running rough, the starter is less than 2 months old, just had all of the electrical re-done. I have a power steering hose leaking (dont think this has anything to do with it) and what i thought was the sending unit for my oil pressure was bad. Yesterday driving home my oil pressure pinned, but i was sure it was the gauge because after i turned it off it would take like 5 min but would return to normal, when you start it, it spikes at first then sometimes goes back to normal sometimes doesnt (started and shut off a few times last night) my question, is it the gauge or is there another cause? and if it isnt the gauge, any idea what it is, the only fluid leaking is power steering fluid though. thanks ya'll

tjwalker

You have more than one thing going on.

The oil pressure issue is likely a faulty oil pressure sending unit, located directly above the oil filter. They are a common fail. I recommend purchasing this directly from Jeep for the best reliability/accuracy/mating with your factory gauge. Well worth the extra $20 for an OEM sending unit.

As for the hard start, basics first. Be sure tuneup hardware is fresh. Champion copper plugs gapped to .035, new plug wires, distributor cap and rotor.
The importance of fresh tuneup hardware to a quick start cannot be overstated.

If you consistently have an extended cranking time when the engine is COLD only (say the first start of the day), then you may have a leaky check valve in the fuel pump assembly.

Try the poor mans prime test to help isolate this with a COLD engine.

1. Turn key to ON position (do not crank the engine!)
2. The fuel pump will energize and run for a couple of seconds
3. Turn key to OFF position
4. Repeat above a two more times
5. NOW crank the engine over

If the engine starts quickly and cleanly after performing this procedure, you may have the check valve issue. If it starts and runs poorly for a few seconds, it could also be a leaky fuel injector resulting in the bleed down and the stumble upon startup is the engine clearing the excess fuel that has leaked into the cylinder because of the faulty injector.

jeepboy4life

I researched it and found out it was the oil pressure sending gauge, that will be on saturday, but it doesnt start hard in the cold, when its cold or first of the day i hit it once and its fine, fires right up. But once i drive to campus (half hour) and let it sit there for 6 hours, in the sun light on a warm day it wont like to turn over and will take a while, the starter and alternator are brand new, i believe the tune up was put on with the last oil change. thanks

jeepboy4life

I found out what it is but still have no clue of to fix it. The computer says its PO118 which is "high voltage coolant sensor" any suggestions

tjwalker

Most likely a faulty "coolant temperature sensor". Here is more on that code.

http://www.obd-codes.com/p0118

Can't recall offhand if a 96 has 2 coolant sensors or one. If it does have 2, one is for the computer, one is for the gauge. I think the one for the gauge is in the head; the one for the computer in the thermostat housing (which is the one you are concerned with). If it only has one coolant sensor, it is in the thermostat housing.

Also; a code doesn't just mean the sensor. It means the entire "circuit" of which the sensor is one part of. That means that other things in play include the connector (clean with electrical contact cleaner and add dielectric grease) the wiring, (check for opens/shorts) and the computer itself. But the sensor ITSELF is primary suspect #1.

jeepboy4life

Thanks, another question, can I unplug that sensor and drive it bc right now I'm at college and live an hour away, I need to get it home before I can work on it

tjwalker

Does it run now? If it does, then you could try driving it home. I wouldn't unplug it.

It really is an easy repair if you are just replacing the sensor, so I'd consider doing it right away.

Basically remove the connector, unscrew the old one and install the new one and reconnect. Should take all of 10 minutes. You will lose a very small amount of coolant (put a pan underneath), but you don't have to drain the coolant for this job.

jeepboy4life

The problem is I have the part at home, I know its a quick fix, and yes it runs now

tjwalker

If it runs, then drive it home. It is unlikely that you will have a problem. Leave the sensor plugged in, unplugging it is more risky from an engine management standpoint.