4.0 SOHC wont start. No spark Need asap please

[Kingoverace]

My 00' Xploder 4.0 SOHC cranks but won't start. I have power coming from the computer to the coil pack. I just replaced the coil pack 2 weeks ago, but tried another one just now just in case, same result (no spark). 2 weeks ago it wouldn't start with no spark but a new coil pack fixed that. Checked all fueses under hood and under dash. I watched the theft light over and over again. Seems like its doing what it should (flashes until I turn key, stays lit a few seconds then goes out). I don't even smell gas but I can hear the pump when I turn the key. I think I can rule out the PATS, coil pack, fuel pump. My last 2 guesses are timing chain( seems right but I would imagine unlikely) or crank sensor...any input or questions?

 

[Snoranger]

If you have power at a known good coil pack but no spark you have no ground pulse. It could be from: ( in no particular order)
- bad computer.
- bad crank sensor.
- wiring problem. Either from the crank sensor to the computer, or from the computer to the coil pack ( unlikely that all 3 wires had a problem at the same time. )

 

[Kingoverace]

ok thanks. Just wanted to confirm. Going to try a new crank sensor.

 

[Snoranger]

Where in Jersey are you? I've got a spare crank sensor you could try if you're local.

 

[4.0B2]

don't shoot the parts shotgun at it...
slow down... research, find the problem.

have any codes?
timing could be it... don't rule that out, how many miles are on it? has it ever been changed? seems weird you have zero spark though, even if it's not timed right.. you'll have spark usually, just at the wrong time.

if you want to just try parts, yes start with the crank sensor. Does that one have any cam sensors? same thing...

 

[Snoranger]

Does that one have any cam sensors? same thing...

Doesnt matter on a wasted spark system... they only use the crank to trigger the spark. The computer doesnt care if #1 is up for compression or exhaust stroke, it fires for both.

 

[RonD]

Bad crank position sensor (CKP) or wiring should give a P0335 code and set CEL

I think the tach also uses the CKP, via the computer, does the tach move, even a little while cranking?

An OBD II scan tool can confirm if CKP is sending a signal when engine is cranking, or if code P0335 is set

On the older CKP sensors you could use a Volt Meter set for AC volts and then unplug the sensor and put meters probes on the sensors contacts, then turn engine over, should get .5-1.0vAC

 

[Kingoverace]

Would of loved to use my OBDII scanner but i lent it out of course...
Anyways I went to put the new coil pack back on from 2 weaks ago and found a wierd looking "thingy" that really could resemble a ground in my mind. So I put that on under with one of the bolts used for the coil pack. It started right up. Sounded normal. Drove it around the block. Started up like 3 more times. As soon as my dad came back with the Crank sensor it did nothing again but crank. Instead of returning it I just through it on and it fired right up again. So it was the Crank position Sensor...i hope.

 

[Kingoverace]

Assuming that was just the problem, I guess I def owe this thread section a favor. Knew it was a excellent idea but now I'll have to keep a closer eye on it to help anyone else. "Pay it Forward"

 

[Snoranger]

Would of loved to use my OBDII scanner but i lent it out of course...
Anyways I went to put the new coil pack back on from 2 weaks ago and found a wierd looking "thingy" that really could resemble a ground in my mind. So I put that on under with one of the bolts used for the coil pack. It started right up. Sounded normal. Drove it around the block. Started up like 3 more times. As soon as my dad came back with the Crank sensor it did nothing again but crank. Instead of returning it I just through it on and it fired right up again. So it was the Crank position Sensor...i hope.

You mean a weird little "thingy" like this:

 

[Kingoverace]

Somewhat similar.