xj issues

gmc2006

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Feb 27, 2008
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Coats
ive got a 91 xj, when i first got it the auto shutdown relay was bad and it wouldnt crank, i got it to crank and the block was caracked at a freeze plug, so i swapped a motor and now it wont crank, im not getting power to the coil or anything, the only thing i can think of is the crank sensor is bad, any other ideas??? ive checked all fuses and relays and they're good. can anyone tell me how to check the crank sensor with a test light or multimeter??? im not the best with troubleshooting wiring. we also swapped the computer with a computer from a running jeep. Thanks in advance

Ben
 
I didn't know they had a crank sensor in 91
I'm in the process of putting a motor in my 91 XJ with an engine from a 93 XJ
I have the motor semi torn down for a gasket/seal rebuild and I can't remember seeing a crank sensor.
 
Does the engine turn over with the starter ?
If so there should be 5 volts on one side of the crank sensor .
here is some more help

1. When the vehicle does not start, check the Crankshaft Position Sensor (CKP) and the Camshaft Position Sensor (CMP) signals, both need to be present to start and run.

2. Verify the power supplies to the PCM at pins 3, 9.

3. Verify the grounds to the PCM at pins 5, 11, 12.

4. Check the operation of the check engine light. In the case of a PCM failure, the light may not function at all. This would indicate a PCM problem.
here is how to check the coil

1. Unplug the ignition coil connector.

2. Check for B+ on the Dark Green/Orange wire at the coil when cranking.

3. If OK, connect a test light to B+.

4. Check for a flash of the test light indicating a pulsed ground. If OK, replace the coil

I would also check the grounds if you do not have a a good ground it will not start We had a XJ do this to us outin the woods .
 
ok, ill chevk again when i get home, it does turn over and when i checked the plug for the crank sensor las night there is a ground but no positive voltage getting to it according to the test light. i can only think that it would be the computer but one thing i did notice is when i turn the key on i can hear the computer and when i run the test light on the 3 wires for the crank sensor it changes its tones so im guessing that its working and the sensor is bad, im just gonna swap the sensor tonight and see what happens. also, willdman, there is no power going to the coil so i dont know if its also bad or not.
 
hey wildman, just noticed you're from garner, might get you to come by and take a look at this thing if i cant get it runnin if youre available.
 
If it is an auto did you try to start it in N?
 
gmc2006 said:
hey wildman, just noticed you're from garner, might get you to come by and take a look at this thing if i cant get it runnin if youre available.
Click to expand...
I am pretty booked this sunday but off on tuesday so I could swing out there then .
 
Does it turn over when you try to start? If not, then the NSS could be bad. If the neutral safety switch is bad, it won't even start in neutral. There is a harness coming from the NSS to a harness on passenger side of engine. I can't remember which two wires it is, but if you cross the two,it should start.
 
yea, it does turn over but it wont crank, got the codes out of it and its showing a cam sensor code so im thinking the distributor may be bad (as the cam sensor is in the dist.) going to buy a new voltmeter tomorrow and start checking voltages as the old one lost the battle with a 4x8 sheet of 1/2" steel. thanks for all the help everyone!!!!
 
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