Ok hive mind...this is driving me nucking futs!

Background info: Aug 2018 ish...Wife was driving her 2001 Durango 4.7L and it over heated on her...and dropped #8 valve seat. Life and winter got in the way not to mention my 2000 Durango dropping #2 valve seat so she sat on the back burner until now. Fast forward to now, I replaced the heads with another set off a donor 4.7L engine, replaced timing chains and gears (used proper spec'ed N VIN coded timing set), new plugs (Champion copper, gapped .040) and new 4 hole injectors. Ended up replacing the slowly failing AC pump and water pump and now she is 100% back together...and will NOT start.

Replaced the cam shaft position sensor and the crankshaft position sensor off the donor motor. no fire....also tach not moving....re-installed cam shaft sensor (original) tach moves when cranking..still no fire

Verified that I have spark by using another coil over plug and old sparkplug and I have spark on all 8 cylinders with the test...also checked all 8 installed coil overs and they get spark (pulled coil overs put in known good plug cranked and see spark when grounded against metal...pulled and cleaned all plugs again..

When trying to crank it KINDA tries to run but never catches...but only when the key is "bumped" (momentarily twist to start then let go)
.
Won't fire on starting fluid

Am at a loss...what am I missing here?

Might be missing something I've done/checked...any ideas???

Thanks,

Steve

 

Won't fire on starting fluid, but, you have spark? That seems really odd. Does the engine sound right when cranking? If it seems a little off, I would be tempted to do a compression test.

 

Besides not firing, when engine cranking it sounds pretty normal...will do a compression test later today.

 

You're probably a pro at this by now but are you sure the timing is right?

 

Unfortunately I probably am a pro at this now . Spun the motor over 2 or 3 times by hand to verify timing....now leaning towards a bad crankshaft position and or camshaft position sensor.

 

Had this issue myself and went to orileys and got a standard ignition camshaft sensor. It was 30 bucks unlimited lifetime warranty.

 

Went the same direction and purchased both the Camshaft and Crankshaft sensors from O'Rileys and no joy. I asked the question about sensors on another thread, went ahead and ordered Mopar sensors and the first one should be here Wednesday. with the other one on Friday.

Could this have something to do with the factory security system in the Durango's ???

Steve

 

Yes. But, if it was a security issue, the light in the dash should be on, or blinking.... one of the two.

 

Update: Mopar branded Camshaft Position Sensor installed (Crankshaft Position Sensor due to arrive on the 10th). No real change. And I did try the lock and unlock sequence with the door key just to see and HeyYou was correct in that the security light should be on or blinking, it is not doing either so no change there. I swapped out the Crankshaft Position Sensor with one of my older ones and still no joy.

It will crank fine, and SOMETIMES ALMOST start but will not run. I re-checked grounds, cleaned and re-connected a couple of them...

Any other suggestions???

Steve

 

Results of compression tests?

Hook up a battery charger and let it crank a good long time. Try cranking with pedal to floor.