- Location
- Seattle, WA
quinnt - did you ever test the CPS that you put in to verify that it is working?
crankshaft/camshaft position sensor issues
- Thread starter quinnt
- Start date
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
How do I test it? Is there other stuff I can test and how to I test that?
- Location
- Seattle, WA
CPS TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines
1. Near the rear of intake manifold, disconnect sensor pigtail harness
connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (A-B-C) looking into
connector left to right with the part with the notch in the middle on
the right) Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace
sensor if a low resistance is indicated.
4. Rattle the CPS with a screwdriver & zap it with a heat gun while the car is running. Any changes? If so... replace the CPS.
1. Near the rear of intake manifold, disconnect sensor pigtail harness
connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (A-B-C) looking into
connector left to right with the part with the notch in the middle on
the right) Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace
sensor if a low resistance is indicated.
4. Rattle the CPS with a screwdriver & zap it with a heat gun while the car is running. Any changes? If so... replace the CPS.
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
Thanks! can I test the Cam sensor in the same way?
I'll be testing tomorrow.
I'll be testing tomorrow.
- Location
- Seattle, WA
Cam sensor test (from memory, you may want to search to double-check):
a) Do not unplug the cam plug, instead use two paper clips and push them into the back of the connector to make connection with the pins. Use a multi-meter on the paper clips.
b) With the engine cranking the voltage should alternate between 0V and 5V.
a) Do not unplug the cam plug, instead use two paper clips and push them into the back of the connector to make connection with the pins. Use a multi-meter on the paper clips.
b) With the engine cranking the voltage should alternate between 0V and 5V.
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
Ok so I've been extremely busy and am just getting back to this now. I tested what I think was the right plug to test the crank sensor, i got between .3 and . 5 ohms. Bought a new crank sensor from Jeep, still no go. Can someone post a picture of the sensor I'm suppose to be testing to make sure i have the right one? what else could it be if both the crank and cam sensor are now ok?
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
bump
I've gotten a 1391 for an unsynced cam pos sensor(but it still ran). At this point, I'd go ahead and spin the engine clockwise by hand(3/4" socket on the crank pulley) and get it to 0* at the end of the compression stroke. You'll have to pull off the coil rail, remove sparkplug #1, and have someone put their finger over the hole to feel the air pushing out at the end of the compression stroke(crank spins 2x for every cam spin, so you could have to spin it another 360*). You should take the e-fan out to see the mark around the crank pulley better; probably need to shoot some brake cleaner in the area or wipe down. Now go ahead and unbolt and remove the the cam position sensor assembly(including the shaft that goes to the oil pump). How's the side play on the shaft? How's the helical gear on the shaft look? Now read this article and properly sync the cam: http://motorage.search-autoparts.co...estandard//motorage/292005/169830/article.pdf
- Location
- on the beach in Ocean View, VA
X2^^
If the previous cam sensor was damaged/stripped, it probably was not aligned correctly any more. When you installed the new one in it's plaxe, it is probably still out of alignment. Start from scratch following the above and see if you get better results.
If the previous cam sensor was damaged/stripped, it probably was not aligned correctly any more. When you installed the new one in it's plaxe, it is probably still out of alignment. Start from scratch following the above and see if you get better results.
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
Ok, got my jeep to what I thought was TDC earlier, realigned the cam sensor unit and it started up. It idled just fine for about 10 minutes, when I got on the road, after not driving it for 2 months I was happy so I gave it wide open throttle, after about 10 seconds she died again and wouldn't start.
I'll try realigning it in the morning but first, is it possible that it just wasnt quite TDC, but was close enough to start up but then stall out during WOT? and the little half circle that you have to align seemed to move very easily, should it be easy to move? It sits around what looks like a nut that a allen wrench would tighten, should I tighten this at all if it should be tighter or should it be fine?
Thanks, almost done!
I'll try realigning it in the morning but first, is it possible that it just wasnt quite TDC, but was close enough to start up but then stall out during WOT? and the little half circle that you have to align seemed to move very easily, should it be easy to move? It sits around what looks like a nut that a allen wrench would tighten, should I tighten this at all if it should be tighter or should it be fine?
Thanks, almost done!
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
bump
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
bumppp
Take it to the dealer, have them put it on the drb machine to see if the signals are sync'd correctly. This will tell you if there are in fact crank and cam signals and if the cam signal is aligned to the fixed crank signal. We can only offer so much advice over the forums without being able to get greasy. Make sure all of the grounds are clean and tight. Go to the NE section of the forum and offer someone some beer, a meal, and some gas money to come over and help.
Last edited:
- Location
- MilkyWay Galaxy
Did you get the right TDC? There are two of them, one is compression the other exhaust!
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
Yes I'm aware of that. I'm pretty sure I got the right one. When I thought I had it at top dead center, a couple of times it just sputtered then died. But if I put the gas petal to the floor it would run until I let off the gas.
Would I be right in thinking that, if aligned for TDC on the exhaust stroke, rotating the half circle 180* would align it of the compression stroke?
We(my friend and I) tried that and it didn't work either. We tried getting it to TDC about 20 times and aligning it, then switching it 180*, before we gave up for the day.
I'm thinking it might be more than just not aligning properly, it might be going to the dealer soon:tear:
Would I be right in thinking that, if aligned for TDC on the exhaust stroke, rotating the half circle 180* would align it of the compression stroke?
We(my friend and I) tried that and it didn't work either. We tried getting it to TDC about 20 times and aligning it, then switching it 180*, before we gave up for the day.
I'm thinking it might be more than just not aligning properly, it might be going to the dealer soon:tear:
- Location
- MilkyWay Galaxy
No it is 360 degrees, one complete rotation between TDC exhaust and TDC compression. It is easy to mistake one for the other IIRC. Trick is to pull the #1 spark plug (IIRC) and put you finger over the plug hole while using wrench to turn the crank shaft via the harmonic balancer bolt on front. Turn it the last bit to TDC and look for air pressure on you finger. If no pressure it is the exhaust stroke.
quinnt
NAXJA Forum User
- Location
- Palmer, Ma/Rindge, NH
Yeah we had top dead center with pressure, signifying compression stroke.
