Crank Position Sensor Write Up - Page 4

chicagoshooter · 12-04-2008, 10:08 AM

2001 XJ

I have a hard start issue, 5 seconds usually. If I turn off the ignition and then start right up, no problems, but the longer it sits, the longer I have to crank the next time...except for when it is cold and been sitting for more than a day, then it starts right away, no cranking.

New fuel pump and injectors have been tested. I was told they were good.

I also have that hesitation when going up hills. Is this a CPS problem?

nepondguy · 12-04-2008, 11:43 AM

Looks like I will have to drop the transmission. Is that a major job or not too bad? I am off to buy a Chilton's or Haynes today. I found someone on the internet that said they have heated up a nail red hot and melted it into the sensor and then pryed it out that way. Might give that a shot. Any advice on the tranny drop?

LunchBoxx · 04-02-2009, 09:52 PM

I have a similar problem, but a bit different. Mine will occasionally not start. Kind of random. I an hold the gas and it will start. If I let off it will die. It will be fine after a minute. Now it is doing this more often and I notice that it is idling rough when it does start. If this the CPS?

Bmoore89 · 07-04-2009, 11:21 PM

Does anyone have a picture of where the wire plugs in at, from the top of the engine? I think I need to replace it, but can't find the plug to test it. I have a 2000, so it should come up on the passenger side, if I'm not mistaken.

99Greenmachine · 07-04-2009, 11:24 PM

Quote:

Originally Posted by Bmoore89

Does anyone have a picture of where the wire plugs in at, from the top of the engine? I think I need to replace it, but can't find the plug to test it. I have a 2000, so it should come up on the passenger side, if I'm not mistaken.

Yes, yours comes up the passenger's side IIRC

.

TonyBoom · 10-15-2010, 10:35 AM

Quote:

Originally Posted by LunchBoxx

I have a similar problem, but a bit different. Mine will occasionally not start. Kind of random. I an hold the gas and it will start. If I let off it will die. It will be fine after a minute. Now it is doing this more often and I notice that it is idling rough when it does start. If this the CPS?

Anyone able to answer this? My jeep is having the EXACT same problem as this one. I found a CPS on eBay for $31, so I'm hoping it is the solution.

**dukie564** · 10-15-2010, 10:53 AM

i would not trust a cps off ebay

TonyBoom · 10-15-2010, 11:15 AM

Well, Autozone has one for $65 so I might pick that one up. At any rate, do you agree that the CPS may be the problem?

Thanks

gonejeepin04220 · 10-15-2010, 03:12 PM

Quote:

Originally Posted by milisakeracing

<start rant here>You make this sound so easy as did the others in various searches I did (google Cherokee and CPS, it's a pretty common problem). Most said it is a 20min job tops and can even be done on the trail. Obviously they either don't have as much stuff in the way, have more room, or it is easier to do on atx trannies. The sensor is in the same place on a 5spd, I've got the same tools everyone else suggested, even two different types, not only wobbly extensions and u-joints but also a flex extension too. The bolts are 11mm, not 12mm as the you mention above but they could have been changed between an '89 Renix system and the newer OBDII systems with the HO engines.

I managed to get the bottom bolt out after about 30-60min of trying different combinations of the above tools and stopped trying to get the top bolt out after 3hrs of trying, even dropping the front driveshaft to get more room! I'm patient, but this is ridiculous. As you can tell, this is a sore spot. I enjoy working on my cars, this was not fun. When a buddy of mine gets here this weekend (hopefully before he gets here I'll have most of it done) we're going to disconnect the tranny mount and angle it down to get a better angle at the top bolt. Oh and you fail to mention that if you lose one of the bolts down that hole for the sensor, you have an even larger headache of trying to get it out via the observation plate on the bellhousing because you really don't want an 11mm bolt rolling around in there. </end rant>

I really do appreciate the great how-to you created, so don't take the above as being flamed. This is the most I've ever been frustrated working on a vehicle and that includes the times it took over a month to track down an elusive fuel problem on a Mazda and the time the Neon's water pump seized and ate 5 valves prompting me to redo the whole top end over a weekend.

after i changed the tranny in my xj i forgot to bolt in the CPA( i just set it in there and forgot) it still ran until i went wheeling and when i shut it off i got no fire.. after thinking about it for a little while i finally figured out the problem. i used speaker wire( because of course the bolts were missing) to set it back in place to get it home. took me about ten minutes and forearm scolds.

salinity · 10-31-2010, 02:41 PM

Just some info for those who may have a similar engine to mine:

I encountered a similar problem to others on here - my 95 2.5L Cherokee 5-speed was running fine (I changed the cap, rotor, plugs, and wires a couple weeks ago). Then, one afternoon it suddenly would crank and just not turn over after running fine that morning. I was getting fuel, just no spark. After searching these threads, I decided to take a chance and replace the crankshaft position sensor before looking into other possible causes. Picked one up at Advanced for around $70.

I don't own extensions, but I found I didn't need them. I have a mini-ratchet and, although it was a little tedious, I was able to remove the old one and install the new one from underneath the drivers side (no ramps, lift, etc). The bolts were 11mm.

Best of all - IT WORKED! I love these forums.

**dukie564** · 11-01-2010, 08:09 AM

glad you got it fixed

jkh · 11-01-2010, 12:05 PM

If you unbolt the crossmember and lower the transmission with a jack it should get you a little more room to work in there.

Seeing this though makes me wish I would've replaced it when I did the clutch last week....

dangerdakota · 03-15-2011, 03:36 PM

could this be the issue with my truck? someone told me it may be, yesterday well driving my jeep died , no spark.. The timming, distributor, started, fuel pump are all fine, it just wont start

ZexGX · 03-15-2011, 04:22 PM

Quote:

Originally Posted by dangerdakota

could this be the issue with my truck? someone told me it may be, yesterday well driving my jeep died , no spark.. The timming, distributor, started, fuel pump are all fine, it just wont start

It could be, or it could be a bad Ignition Control Module and/or ignition coil (if it has a lot of miles on it). I replaced the CPS, distributor, ignition coil, plug wires, plugs, fuel pump, and fuel filter before replacing the ICM (some of those parts needed replacing anyways, like the plugs/wires/fuel pump). Only after I replaced the ICM did the stalling, dieseling, and backfiring go away.

salinity · 03-15-2011, 04:26 PM

I would say it definitely could be. These and other jeep forums are rampant with tales of CPS failures. Mine didn't fail while driving (I just couldn't start it up). You may want to search around for other diagnostic procedures to eliminate other potential causes before jumping in, but I would guess it's definitely a possibility its the CPS.