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00' XJ no start

whitneyj

whitneyj

NAXJA Forum User
Location
Mayville, WI
Searched and troublshot according to everything I could find and I can't seem to figure out the issue:

The Jeep turns over, but won't start. Zero voltage to fuel pump, but getting 11V at the fuel level sender. Fuel pump relay is good. ASD relay is good. Ohm'ed the CPS and it's the same as a new one. Swapped my spare PCM and no change. Grounds are all on fresh bare metal.

Anyone have any ideas?
 
Test/Inspect the Camshaft Position Sensor inside the Distributor Cap. Inspect the CPS wires and wire connector for damage, corrosion, or chafed insulation.
 
It's a 00, doesn't have a distributor. CPS ohm'ed out good. I'll be checking the AC voltage from the CPS when in get home tonight. Apparently that's the last thing to check on the CPS.
 
I think he already said he tested and found no power to the fuel pump.

Is the fuel pump always atg 0 volts? Or do you hear that two second whine when you turn the key to the on position without starting?
 
birchlakeXJ said:
It doesn't have a distributor, but it still has a camshaft position sensor. It is located where the distributor used to be.
Click to expand...

Ahhhh, didn't read that correctly. Camshaft sensor is on the list. What's the ohm's supposed to be for that?
 
When you turn the key to the "RUN" position (Not "Start", but "RUN") the fuel pump should run for a second or two to build up line pressure.

If the Fuel pump does not pressurize the line, I would start there. I would be interested to see if the Computer is throwing a code.

-Ron
 
Zuki-Ron said:
When you turn the key to the "RUN" position (Not "Start", but "RUN") the fuel pump should run for a second or two to build up line pressure.

If the Fuel pump does not pressurize the line, I would start there. I would be interested to see if the Computer is throwing a code.

-Ron
Click to expand...


Thank you, but I've already answered the first part Ron.

As for if the computer is throwing a code-Nope. No CEL.
 
I tested for VAC on pin B and C and came to 0 volts.

The camshaft positioning sensor looks good. It's tight and the wires are good. I peeled back the wire loom to take a look at any potential chafe points and there's nothing.

I'm leaning towards the CPS. Anyone have any other ideas before I replace a $90 sensor?

Crankshaft positioning sensor put out 0 VAC. Going to replace that tomorrow unless someone pipes up
__________________
 
before buying the sensor, try unplugging and plugging it back in. that seemed to work for me.
 
Replaced the CPS and no change. The old sensor's magnetism was also significantly stronger than the new sensor. Not sure if that's important or not.
 
CAMSHAFT POSITION SENSOR—4.0L ENGINE​
DESCRIPTION​
The Camshaft Position Sensor (CMP) on the 4.0L
6–cylinder engine is bolted to the top of the oil pump
drive shaft assembly (Fig. 6). The sensor and drive
shaft assembly is located on the right side of the
engine near the oil filter (Fig. 7).​
OPERATION​
The CMP sensor contains a hall effect device called
a sync signal generator to generate a fuel sync signal.
This sync signal generator detects a rotating
pulse ring (shutter) on the oil pump drive shaft (Fig.
6). The pulse ring rotates 180 degrees through the
sync signal generator. Its signal is used in conjunction
with the crankshaft position sensor to differentiate
between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following occurs:
The interruption of magnetic field causes the voltage
to switch high resulting in a sync signal of approximately
5 volts.
When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following occurs:
The change of the magnetic field causes the sync signal
voltage to switch low to 0 volts.​
​

 
Note from DJ
Checking Fuel Pump Procedure No Power

No power to your fuel pump (check fuses and relays) or your fuel pump is shot.

I would first hot wire the fuel pump, there is an electrical connector on the drivers side near the gas tank, should have three wires to it, hopefully there is a smaller gauge wire on it like mine this is for the sender, so ignore it. Run a pair of long wires from your battery to the connector, one to the + side of the battery and one to the — side of the battery (black preferably) to the black wire of connector, the other color to the probably orange wire of connector to positive side of battery.

The fuel pump should now be running if not you probably have a bad pump.

But you stated that you had no voltage to the pump, this procedure will take care of that problem as a test.

Post back what you discover.
 
jbmoose said:
CAMSHAFT POSITION SENSOR—4.0L ENGINE​
DESCRIPTION​
The Camshaft Position Sensor (CMP) on the 4.0L
6–cylinder engine is bolted to the top of the oil pump
drive shaft assembly (Fig. 6). The sensor and drive
shaft assembly is located on the right side of the
engine near the oil filter (Fig. 7).​
OPERATION​
The CMP sensor contains a hall effect device called
a sync signal generator to generate a fuel sync signal.
This sync signal generator detects a rotating
pulse ring (shutter) on the oil pump drive shaft (Fig.
6). The pulse ring rotates 180 degrees through the
sync signal generator. Its signal is used in conjunction
with the crankshaft position sensor to differentiate
between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following occurs:
The interruption of magnetic field causes the voltage
to switch high resulting in a sync signal of approximately
5 volts.
When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following occurs:
The change of the magnetic field causes the sync signal
voltage to switch low to 0 volts.​
Click to expand...

Would this cause the fuel pump to not receive 12V? The camshaft positioning sensor looks fine, no wires chafed, ect ect. I'll pull the plug apart and test for what 5V's it puts out, just for to know I suppose.
 
djgrayxj said:
Note from DJ
Checking Fuel Pump Procedure No Power

No power to your fuel pump (check fuses and relays) or your fuel pump is shot.

I would first hot wire the fuel pump, there is an electrical connector on the drivers side near the gas tank, should have three wires to it, hopefully there is a smaller gauge wire on it like mine this is for the sender, so ignore it. Run a pair of long wires from your battery to the connector, one to the + side of the battery and one to the — side of the battery (black preferably) to the black wire of connector, the other color to the probably orange wire of connector to positive side of battery.

The fuel pump should now be running if not you probably have a bad pump.

But you stated that you had no voltage to the pump, this procedure will take care of that problem as a test.

Post back what you discover.
Click to expand...


Will do
 
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