tacmedic909

Good morning, all. So yesterday my 1999 Jeep XJ was working fine. No issues at all. Today it's a different story. I get into the seat and try to start it and it's cranking but not starting. For starters the battery is about 6 months old, it has gas and the check engine light is not on. The oil pressure gauge is going up as thr engine turns over and then goes back down when its not turning over. The RPM gauge does not climb at anytime. I'm not sure what the issue is obviously. I've checked the spark plug wires and everything is connected. The wires are only 2 years old and thr plugs were replaced with the wires. Any help would be much appreciated. I'm hoping it's not a fuel pump

SteveMongr

Hard to say but I would try two different things.
1) Poor mans prime. Turn key to on but do not crank engine, should hear the fuel pump for a second or two. Do this twice then try and start engine.

2) When cranking engine press gas pedal to floor. This will cancel fuel injector pulses to 'clear flood'.

Also, when cranking do you smell gas at all?

tacmedic909

I do Smell gas.

jordan96xj

The Tachometer (RPM gauge) does normally move during startup on a 1999 XJ. Although your symptoms could be caused by many things, I would start by testing the crankshaft position sensor (CPS). (use search to find how).

SteveMongr

In that case try option #2
Crank engine and hold gas pedal to floor. If it starts then remove foot from pedal before RPMs get high. It may stumble a moment before evening out.

tacmedic909

I have tried option 2. I picked up a cps Jusr now. I've had this issue before in a previous xj. I'm hoping this is it. If not maybe a relay switch in thr fuse box?

jordan96xj

You can clear a flood by holding the pedal all the way to the floor while starting. This commands the computer to -not- enable the fuel injectors. So pedal to the floor, then crank 6-8 revolutions, then stop. Then foot -off- the pedal, and try a normal start.

If the CPS has failed, there will be no spark, and it will flood again.

tacmedic909

I will try that

tacmedic909

Just giving everyone an update. It turned out to be my CPS. It took some doing but I got it replaced and fired right up. Thanks everyone for their input!