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  #1  
Old August 23rd, 2009, 13:00
LiteEmUp LiteEmUp is offline
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Question Crank Sensor replaced still no start

Recently bought a 1999 Cherokee Sport arrived there it would not barely start and run determined it was getting no fuel did some research and filled the tank above 1/2 tank and it started. Noticed the fuel pump relay was burnt I think the pickup is clogged will get to that in a minute.

When the truck started had a hole in the tube that goes from the water pump to the heater hoses used some epoxy stuff to plug the damn and get the truck home. When I got the truck home I replaced the tube in the driveway when I was refilling the rad with water noticed it was dirty under the hood so gave it a good spraying down to clean it up.After that I was in a crank no spark situation I replaced the cps and am currently in the crank no start situation again.

I have checked all fuses, swapped asd relay , made sure the battery is fully charged and threw last nights chicken bones at it while chanting in what I figured was a pretty convincing curse removal chant.

I have checked the cps sensor and get the same readings on the old one and the new one A B C looks like C B A if you flip the sensor as I do not have the notch to place at the right as I have read it pretty much looks the same on either side. I have a reading of infinity on one side and 600 to 700 0hms on the other side.

I am going to go back where I bought the cps and exchange it tommorow I am just wondering if I am missing something more to check. As well is there a way to relably test the main computer as I am wondering if it is ok too now? Thanks for your time I swear I searched this and other forums before posting I am hoping I will get a unique perspective if possible.
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  #2  
Old August 23rd, 2009, 14:21
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Blaine B. Blaine B. is offline
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Re: Crank Sensor replaced still no start

What about the cam position sensor beneath the distributor cap?

I had similar symptoms and replaced the crank sensor thinking that was definitely the problem and it wasn't. Replaced the cam sensor and wallah, fixed.
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  #3  
Old August 23rd, 2009, 16:06
LiteEmUp LiteEmUp is offline
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Re: Crank Sensor replaced still no start

Ok checked voltage and have .69 volts no matter what while testing at sensor. Then I checked PCM voltage being delivered to cam sensor and I again have .69 volt at the PCM.... really do not know how to interperet the results.
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Old August 23rd, 2009, 16:18
X1994J X1994J is offline
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Re: Crank Sensor replaced still no start

Maybe i missed this, did you pull the dirtributor cap and make sure there is no moisture in there? Also you can put a test light on the wires going into the coil, when you cycle the key on you should get a burst from each wire, that will tell you if you'r getting spark all the way to the coil.

Also watch the Tach as you're cranking it, if it's not showing RPM while cranking chances are it's either the CPS or Cam Position Sensor, as the computer needs both of these to recognize RPM. Did I explain that correct???

Last edited by X1994J; August 23rd, 2009 at 16:27.
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  #5  
Old August 23rd, 2009, 16:43
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Tim_MN Tim_MN is offline
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Re: Crank Sensor replaced still no start

Testing is the best place to start on your end.

Describe your no-start, what do you do, what do you hear (fuel pump primes for 3-5 seconds?), what does the Jeep do ? Does the starter turn the motor ? Do you have any spark at the spark plugs ? Have you tried a little starter fluid in the throttle body ? Do any of the cylinders fire at all ? When trying to start do the Fuel gauge and Volt gauge function normally or do they seem dead ?

If the battery was allowed to run low or was disconnected, you may have to use the gas pedal to get the engine to start.

.
The Camshaft Position Sensor is located in the distributor on all engines.

For this test, an analog (non-digital) voltmeter is needed. Do not remove the distributor connector from the distributor. Using small paper clips, insert them into the backside of the distributor wire harness connector to make contact with the terminals. Be sure that the connector is not damaged when inserting the paper clips. Attach voltmeter leads to these paper clips.
1. Connect the positive (+) voltmeter lead into the sensor output wire. This is at done the distributor wire harness connector.
2. Connect the negative (-) voltmeter lead into the ground wire.
3. Set the voltmeter to the 15 Volt DC scale.
4. Remove distributor cap from distributor (two screws). Rotate (crank) the engine until the distributor rotor is approximately in the 11 o'clock position. The movable pulse ring should now be within the sensor pickup.
5. Turn ignition key to ON position. Voltmeter should read approximately 5.0 volts.
6. If voltage is not present, check the voltmeter leads for a good connection.
7. If voltage is still not present, check for voltage at the supply wire.
8. If 5 volts is not present at supply wire, check for voltage at PCM 32-way connector (cavity A-17). Leave the PCM connector connected for this test.
9. If voltage is still not present, perform vehicle test using the DRB scan tool.
10. If voltage is present at cavity A-17, but not at the supply wire:
a. Check continuity between the supply wire. This is checked between the distributor connector and cavity A-17 at the PCM. If continuity is not present, repair the harness as necessary.
b. Check for continuity between the camshaft position sensor output wire and cavity A-18 at the PCM. If continuity is not present, repair the harness as necessary.
c. Check for continuity between the ground circuit wire at the distributor connector and ground. If continuity is not present, repair the harness as necessary.
11. While observing the voltmeter, crank the engine with ignition switch. The voltmeter needle should fluctuate between 0 and 5 volts while the engine is cranking. This verifies that the camshaft position sensor in the distributor is operating properly and a sync pulse signal is being generated. If sync pulse signal is not present, replacement of the camshaft position sensor is necessary.
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I'm starting to realize people on the Jeep forums are highly expert mechanics .....

Last edited by Tim_MN; August 23rd, 2009 at 16:48.
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  #6  
Old August 23rd, 2009, 16:56
lawsoncl lawsoncl is offline
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Re: Crank Sensor replaced still no start

If you're not seeing 5-volts (or near that) supply voltage to the sensors, such as the TPS, then that needs resolved. Start checking the fuses under the dash and the power dist center.
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Old August 23rd, 2009, 17:21
LiteEmUp LiteEmUp is offline
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Re: Crank Sensor replaced still no start

Ok new distributor cap, rotor and wires.Voltage at the coil is 1.09 volts.Tach , fuel and voltage appear dead even when cranking tach does not move. No Bu5 has shown up and disappeared a few times during this.
Fuel pump primes and stays on for appropriate amount of time I have no spark condition and new cps installed. I did the cam sensors test and as reported above .69 volts. I have checked every fuse under kick panel passenger side and under hood in Power distribution center had a fuel pump fuse blown repaired that.
Hope I answered everyones questions .. about the cps I recieved I am getting infinity from one side of the sensor and 600- 700 ohms from the other side is it good ?
A-B and B-C is what I mean from both sides as I cannot discern what is A and what is C. Sorry forgot to reply to starting questions I have fuel at the rail and cranks and cranks and cranks and no spark.
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  #8  
Old August 23rd, 2009, 19:21
lawsoncl lawsoncl is offline
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Re: Crank Sensor replaced still no start

You should have 12 volts at the coil between the dark-green/orange-stripe and ground. This is the same feed to the injectors as well. The computer controls the ground side of the coil and injectors. If you don't check the ASD relay and fuse 21 in the PDC.

You should have +5 volts at the TPS sensor, camshaft, and crank sensors between the orange wire and battery ground. If that's not there, then the engine computer may not have power.
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Old August 23rd, 2009, 22:15
jeffrey803 jeffrey803 is offline
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Re: Crank Sensor replaced still no start

Hi Litemup,Check your TPS,they do not like to get wet as stated in your first reply(you washed your engine to clean it up a bit).just maybe your problem,let us know how you make out.
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  #10  
Old August 24th, 2009, 04:10
LiteEmUp LiteEmUp is offline
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Re: Crank Sensor replaced still no start

Quote:
Originally Posted by lawsoncl View Post
You should have 12 volts at the coil between the dark-green/orange-stripe and ground. This is the same feed to the injectors as well. The computer controls the ground side of the coil and injectors. If you don't check the ASD relay and fuse 21 in the PDC.

You should have +5 volts at the TPS sensor, camshaft, and crank sensors between the orange wire and battery ground. If that's not there, then the engine computer may not have power.
I do not have 5 volts at the coil nor at the cam sensor. I swapped the ASD relay and the satrter relay and it is still starting is there a more definitive test for the engine computer that I can do to verify the CPU ?
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  #11  
Old August 24th, 2009, 08:25
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gradon gradon is offline
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Re: Crank Sensor replaced still no start

You can start unplugging the sensors on the manifold side one at a time and then see if you get 5v at the cam. You shouldn't be getting 700ohms on the cps(mine have ranged from 3.5-6 megaohms, per fluke). I had one cps that was shorted out(0 ohms) and it gave me the no bus/no connectivity to the obd2 port.
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Old August 24th, 2009, 08:25
lawsoncl lawsoncl is offline
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Re: Crank Sensor replaced still no start

So it is working after swapping the ASD relay?
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  #13  
Old August 24th, 2009, 09:07
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winterbeater winterbeater is offline
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Re: Crank Sensor replaced still no start

Quote:
Originally Posted by LiteEmUp View Post
and it is still starting is there a more definitive test for the engine computer that I can do to verify the CPU ?
I guess youu mean still NOT starting or you wouldn't be asking!

About the only things you can check at the CPU is voltage in and voltage out. Unplug the sensors and check for 5V output from the CPU.
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  #14  
Old August 24th, 2009, 11:58
LiteEmUp LiteEmUp is offline
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Re: Crank Sensor replaced still no start

I meant once switching the asd and starter relay it was still cranking (thus the asd relay was working in the starter ) sorry for the confusion .
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  #15  
Old August 24th, 2009, 14:27
Firewater Firewater is offline
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Re: Crank Sensor replaced still no start

i just want to bump this 'cause I'm having the same problem . . .only difference is that it happened out of nowhere while on vacation in Maine. Stopped to get videos and just like that . . .crank but no start. i had no choice but to send to local dealership and get ride home with tow truck.

dealer changer CPS (what I suspected) to the tune of $300. But lo and behold, no dice. Seems like some of you guys know way more than the dealership. I'm stuck without a ride in the middle of nowhere. Feeling really helpless. I'll let you know if these guys figure this thing out.
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