BlueRidgeMark

That's appreciated. The reason we are stressing it is that aftermarket units are so bad that a newly replaced aft4ermarket CPS is just as suspect as a 25 year old CPS that's never been touched.


Not sure what that wire is. Where is it located?

dt750

wiring is under the steering column has about 3 black wires going into it on the one end and there's a hole in the other end like a wire would go there. well one problem is found, when i went out to hook up the crank sensor the wires didn't feel right that went to the crank sensor....little bugger pulled right out of the bell housing, the bracket that bolts to the bell housing is still there but the sensor pulled right out....I reckon whether the sensor is bad or not i'll be replacing it...lol

wonder if a crank sensor out of a 1996 would work, I have an old plow jeep at a friends I could rob the part and at least see if it runs.

cam sensor has power to it and tested good...again if I did the test right...lol, grounds by coil have been cleaned and appear good. yes I unbolted them and cleaned them..didn't just look at them..lol

BlueRidgeMark

Hah! Good find. That may not be ALL of the problem, but it's certainly a problem.


Will a 96 fit a 98? Dunno, so, let's try my favorite trick. I'll ask a parts store.

NAPA says a 96 can use part number ECH CSS630 and a few others.

NAPA says a 98 can use part number ECH CSS638 and a few others.


Kinda looks like it's a no. I'd be happy to be corrected if someone knows otherwise.

96 was a mongrel year, especially electrically. 97 was the changeover to new electrical stuff (OBDII compliant). You can find some 96s that are more like 95s and some 96s that are more like 97s. It's a trial and error thing sometimes.

Noah911

I would not really take offense even if you were trying to be arrogant towards me. I would likely still attempt to help you even if you were.. I worked in Emergency Departments for many many years taking care of and helping out plenty of arrogant asshats.. This never stopped me from providing the same level of care I would want my own Mother to recieve. I did not think you were though.

Alright, the gas gauge is not working, and you have no spark. And, you notice there is zero power being delivered to the CkPS sensor...

The fuel pump, along with the fuel gauge operation, and the ability for your Jeep to produce spark may be tied together having problems.. and possibly a problem with the CkPS sensor and also its wiring too.. All of these are tied together to one another via the ASD relay. Have you looked for power there at this relays terminals to see if there is 12V getting to it, and this relay is operating correctly? You can test the relay easily with a voltmeter, feel for it to 'click', or swap it out for your windshield wipers relay to help determine this for you. Something in this particular circuitry sounds like it is faulty to me. It could be from either direction, before or after the relay, with any of the components in the systems that are all tied together here.

You say your CkPS sensor tested fine.. I don't know how you can say that though? How did you test it? Either way, if it is not a Mopar brand it should in my opinion probably be replaced. Although, it may not need replacing in order to be able to find the reasons for your problem. How did you test it though if it is not recieving power?

(edited to add):
You cannot accurately test the CkPS sensor you have in your Jeep for resistance.. It does not work that way, and it would be misleading.

dt750

learned something new. that's how i tested was for resistance. lol. I have to get a new ckps as the bracket was broke off from the sensor it's self?? I swapped the relays and got no change. I tested were the ASD relay plugs in and had power at #30 with the key off and #85 with the key on. if I unhook the battery and hook it back up my gas gauge will work briefly and then drop right back to empty. I just used a test light to see if the ckps had power first with the key off then with the key on, then with the key turned and they jeep trying to start. the light never lit up on any of the 3 wires that connect to the ckps.

I'm gonna look for a chiltons manual for it tomarro and hopefully i can get a wiring diagram to see about the wires I posted earlier.

Noah911

When you test the CkPS in this model year of Jeeps (and most all other vehicles).. You can check to see for a proper ground, for wether or not it is recieving proper voltage, and for the signal it produces.

You are actually able to get a reading of Ohms when testing it for resistance. It is not in any way considered to be an accurate value, or relevant information though.. If you utilize the meter correctly incorrectly - Lol... by setting the meter to read way outside of the ussual parameters you are supposed to normally use.. Then, you may be able to ascertain a reading kind of 'close enough' to mean something sort of valuable. Even this type of round about way of obtaining an Ohms reading is still not worth much though, since it is still considered to possibly be highly innacurate... it would end up being a fluctuating numbers value that needs to be averaged, and then converted. This is because it is a 'Hall-Effect' on/off sensor...

To test the signal being produced by it you can do it one of two ways. Manually hand turn cranking the engine yourself.. with the dvom hooked up you should see it normally produce an on/off reading of 5 VOLTS. You can do it this way. Or, keep the meter hooked up to the CkPS signal wire. Pull the ASD relay so the Jeep will not start on you. Then, turn the ignition key to allow an extended crank time while you look for the results on your meter. It should produce an on/off signal of 5 VOLTS. However, it happens too fast to see the on/off actually occur... So, you will be looking at the average reading. It should be close to a steady 4, 5, or possibly 6 VOLTS. If it is steady 0.0 or like a steady 7, 8, 9 . . . 1, 2, or 3 Volts? Then, you are looking at problem readings.

dt750

sounds good, i'll give it a try tomorrow am to see if I get anything out of the sensor and thanks for all the help....sadly i told my wife i wasn't gonna hook up the remote starter set up in the jeep because i didn't want to mess anything up with hunting season coming up....I guess I don't even listen to my own advice...lol

awg

there needs to be 5V and earth at the sensor or nothing will happen, so it seems you have some issue right there

the factory service manual has electrical diagram and diagnostics..find member cruiser54, go to his website, and download the manual

the electrical diagram shows the wire color and where the sensor gets its 5V, you could have a wiring issue or short

dt750

thanks for the info, i'm gonna check it out right now...and good morning to ya awg. I guess I ain't the only morning person on the forum..lol

Noah911

To be sure you understand. The CkPS should be recieving a constant 5 VOLTS from the ECU-PCM providing the power to it. Sometimes people get confused about this, since the CkPS sensor also sends an intermittent 5 VOLTS back as a signal...

The connector may simetimes be a flat rectangle, round style, or more oval like the one below (which is probably the one your Jeep has?). The wiring and connector pin/terminals identification remains the same.. So long as you are looking at it oriented correctly with the center tab thing how it is shown below. I don't know all the wiring colors leading to the CkPS connector. I know the ground should be a tan brownish/yellow tracer wire though since it is a Chrysler...

You want to be able to see a constant 5 VOLTS to the A-pin/terminal supply, coming to it from the PCM with the ingnition key turned.


A= Supply B= Ground C= Signal

dt750

I took your advice awg and went to cruiser54's sight and searched the manual he had. found out it is a 5volt orange wire from the pcm that powers the crank and cam sensor. after fiddling around pulling connectors and cleaning things I now have power to the crank sensor....yea one problem solved...not sure how, but i'll take it...lol.

I hate to just throw parts at things, but I think I'm gonna replace the crank sensor since it's broke anyway and see what happens. wish me luck...lol

I'm receiving a constant 5.2 volts at all 3 of the terminals.. fairly certain that ain't supposed be..lol with the key on

dt750

while testing the
crank sensor with a test light, (light was grounded to the batter) when i would touch the grey/black wire the computer would click and my fuel gauge would read correct. with the 5.2 volts i'm reading at the ground, i'm guessing i lost a ground someplace. does that sound right?

gootz4u

I am not sure if this is related to your problem, but my jeep was turing over and would not stay on. It turned out that is was the ground wire that connects to the fuel pump resister which is on the fender. One of the green wires was loose and I connected it back, it worked. I disconnected it and turned on the jeep and it just turned over but would turn off immediately. I secured the wires to make sure they would not come loose anymore. Just a thought.

dt750

I'll run out and take a look at this point i'll try about anything....lol thanks

edit: i don't see any green wires on my fender either of my fenders

lawsoncl

For clarity for future readers, this only applies to the newer 3-wire CPS sensors. The older 2-wire sensors are literally just a coil wrapped about a magnetic rod, and they produce a/c pulses as each gap in the flexplate/flywheel goes by the sensor. You can do a sanity check of those sensors by measuring their resistance with a meter. It still doesn't prove they're good, but if it's an open circuit or resistance is way too low, then it's definitely bad. You can also look for a/c voltage with a meter while cranking.