soundrew

Hello,
Set up: My 2000XJ has a tight engine with 125k and it pulls hard. No mechanical noise except the alternator bearing whines a bit.

I was driving home yesterday (in 95 degree heat) and going about 65mph. The coolant temp was normal (210 ish) and it was running about 55psi oil pressure. I had the AC on. I felt a shudder/hesitation for only a second. A few seconds later another, then it died. Pulled over on shoulder. Looked at temp- it was OK, CEL was on. I turned the key- it started and idled. Gave it some gas and it died again. Tried this twice more- ran for a second or two and died, then finally it wouldn't start at all. That when I noticed check guages light on and oil pressure needle on zero. Hmmmmm.

Thinking it might be fuel pump relay, I swapped relay with AC relay (same part number). No dice. Assumed fuel pump. Had it towed to a nearby repair shop and got a ride home (50 miles).

I got a call from shop this morning and mechanic says it's oil pump and he thinks it took out the cam too- suggested a new motor! I told him it only ran with no OP for a few seconds and I never heard any knocking, rattling, etc. if the cam lobes were wiped. He said he didn't pull the valve cover but thinks the cam gear (that drives oil pump) is toast. I asked him how that could explain it not starting. He said I need a new engine again. I asked him if 4.0 was an interference motor and he didn't know what that meant. Grrrr. Tomorrow I'm towing it back home.

He said it threw several codes but wouldn't elaborate on what they were. He never tested fuel pressure or spark.

Any ideas? Is it possible the fuel and oil pump went bad so close together? Can the computer disable the ignition or fuel system if there is a sudden drop in oil pressure? Might it be the CPS?

Please let me know your thoughts.

Thanks.

1976Mustang

I would first suggest getting it away from that shop. they guy is clearly trying to make you pay him a few grand for something that doesn't need to be done. Or demand he gives you the error codes.

Once you have the codes (Either from him giving them to you or you having the car towed home and pulling them yourself) you can look up what they are and start from there.

freegdr

deff find different mechanic ,first thing is check for spark -theen fuel wont have oil pressure if it aint running also check grounds poor one have strange effects on jeeps

soundrew

I picked up my XJ today (thanks AAA) and got it back home. It has CEL codes for ignition coil misfire (3 different cylinders), a transmission fault (perhaps generated as I coasted off the highway with engine off and still in drive) and cam sensor.

The mechanic who looked at it seemed to think that the oil pump shaft broke and damaged the cam gear that drives it. He showed me a piece of metal he pulled from the crank sensor cavity. He said that a used engine wouldn't be much more than a cam replacement. Ugh.

I'm thinking I should pun the oil pan off and have a look-see. This thing was running great and maybe ran without oil pressure for 10 seconds. I can't believe the whole motor is toast.

odgreen

That mechanic is retarded. First thing first the CPS has no way of picking up a piece of metal from the oil pan since it is mounted on the OUTSIDE of the motor! If the CPS had a chunk o metal on it that would cause a no start issue. The CPS runs off of magnets and a chunk can cause a false reading. Try a known good CPS and try to start it. There could also be a tripped asd (auto shut down) relay or fuse blown. Start with the simple things first.

That mechanic gives truthful mechanics like me a bad name.

F1Addict

I agree with odgreen, start off basic. First, do you at least hear your fuel pump prime when you turn the key on? Next, check for spark. I'm pretty sure the '00s have coil packs so no ignition coil but they still have a CPS (Crank Position Sensor) and a Cam Position Sensor.

If you've got spark, check fuel pressure at the rail.

soundrew

Odgreen, the mechanic proposed that the metal fragments were from the broken pump shaft/ gear and/or camshaft gear (which he spied through the CPS hole).8 He did not say he looked in the pan.

There is fuel pressure at the rail. I haven't put a gauge on it but it's substantial. When I restarted the car on the side of the road (was able to do that twice before it stopped running altogether) the oil pressure needle was at 0 and the check gauges light was on (in addition to CEL). I'm thinking the mechanic may have been right when he said the oil pump shaft broke. Is it possible that could have affected the CPS somehow and made the motor stop?

What is the best way to determine whether the cam itself is damaged?

odgreen

No possible way. He is full of crap. Check the asd relay and fuse.

hbracing13

Did you do the self check with the trip and odd? And see if the pcm threw a code? I don't know for sure if you can do it on those but worth a try.

The asd relay with disable eveything its like a insursha switch. You either have a power problem to the tcu or pcm or even a ground problem. Or you blew a fuse and are to longer getting power to the relay.

I'm fighting the same problem but yours a way easier atleast you getting a mil light and key on engine off

cruiser54

Get off this cam kick. The mechanic is nuts. There is no way internal camshaft pieces end up between the engine and trans. Listen to what these guys are telling you.

soundrew

Cruiser 54 and all, I will try to get off this "cam kick" but, before I do, I want to clear some things up. First, by CPS I mean cam position sensor- located where the distributor was on older models. The worm gear had some fragments missing and I think the unscrupulous mechanic (there, I said it) assumed that meant the cam gear was toast. I don't think he ever suggested this diagnosis based on anything from the other CPS (crank position sensor back in the bell housing). Am I wrong to think the cam sensor drives the oil pump? Could it be that the two things (loss of oil pressure and no start) are related somehow?

Taking your advice, I will look at relays and check for shorts (I've heard harnesses can rub or burn through and cause trouble.

Please forgive my tunnel vision- I'm kinda new to this XJ world.

Radi

There are links here to the assembly info for the cam sensor/oil pump drive:
http://www.jeepforum.com/forum/f19/4...drive-1265425/

I suspect the PCM shuts down the ASD relay (thus the fuel supply) if there is no cam or crank sensor signal, assuming the engine has stalled. Fire prevention.

freegdr

would not oil pump drive shaft which is mounted below cam shaft position sensor breaking cause this issue op is describeing....

cruiser54

Very possibly now that we know it's the CAM Position Sensor.

What needs to be done is remove the sensor, which indeed does drive the oil pump, and see if the teeth on the cam are okay for sure. Perhaps the gear on the Cam PS are the only ones damaged.

soundrew

I will be looking at cam position sensor/synchronizer, oil pump and cam gear tomorrow. I'll give you an update. If the cam gear is damaged, what is my next step? Can the gear be changed? Is it time for a new cam? I'm sure the lobes and bearings will be fine because, as I said before, it ran with no oil pressure for only a few seconds.

Also, im wondering about metal fragments from the pump shaft, cam sensor/syncro gear and the cam gear. Is it possible those could cause damage? Would they just fall to the pan? I'm not sure those gears are exposed to oil passageways. Please illuminate for me. Of course, I'll be doing an oil and filter change before trying to fire it up (after putting in a new pump if it is broke).

Thank you all for your help.